THE PHILOSOPHICAL DIMENSIONS OF THE ORIGIN OF SPECIES.

John N. Deely

University of Ottawa

Ottawa, Canada

 PART TWO

VI. The Error of Univocally Ontologized Kind-Essences

From the title of this section one might expect it to develop the contention that the specific structures causally accounted for by contemporary science are contrarily related to the texture and sense of the traditional principles governing the recognition of specific distinctions in the world of bodies. Perhaps unfortunately, we must develop a rather more complex contention.

The contention to be developed at this point is that an ontological survey of the landscape of Darwin's world shows that, so far as its metaphysical structure is concerned, the knowledge of evolutionary species has not altered the structure of the traditional species problematic but has, on the contrary, clarified its secondary implications so as to make its options clearer and their alternatives more definite. In showing this, the survey in question shall have, on the one side, to clear away the morass of philosophical perplexities in post-Darwinian thought due not to the accumulation of evolutionary data (as Dewey thought and as commonly supposed) but primarily and directly to those ambiguities and uncertainties latent in Classical Antiquity's notion itself of species, whose features the labor of evolutionary research has forced to the fore. This will be the direct concern of the present section. On the other side, it will remain to show that the forthright acknowledgment and philosophical resolution of these no longer latent ambiguities and uncertainties render the evolutionary data themselves more intelligible in their own line of explanation which is not mathematical (species are not numbers) but that of natural philosophy, wherein are assigned reasons for the changes that never cease around us. This will be the concern of Section VIII below, where the problem of the criterion of evolutionary progress at last comes into view.

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Mortimer Adler was perhaps the first to see clearly and perhaps the only one to state clearly that " most of the philosophical perplexities in post-Darwinian thought are due to ambiguities and uncertainties in the notion of species itself rather than to the discovery of any radically significant facts."¹⁵³ The ambiguities and uncertainties in question, I think, can be traced to seven sources, four of which are matters of properly philosophical argumentation, one socio-cultural, one psychological, and one theological.

1) Most fundamentally, it was the enculturated conception of the eternal heavens which deflected even the most penetrating of the classical and medieval analyses of the ontological character of the natural kinds encountered in common experience.¹⁵⁴ Since the unchanging

¹⁵³ The Problem of Species, p. 10.

¹⁵⁴ For Aristotle and St. Thomas, it was the eternal space-time of the celestial spheres which determined the place and order of sublunary bodies, and so the rigid necessity and formal immutability of their natures. The Aristotelian essences of material beings do not have their cosmological reference to what we understand today by the physical environment but to the unchanging heavens which, as instruments of the separated intelligences, were regarded as the causa regitiva, the governing cause, of the physical world. E. g., cf. St. Thomas, In III Met., lect. 11, n. 487: ". . . in the twelfth book [1073a14-1073b17; in Comm., lect. 9, " The Number of Primary Movers "] . . . the Philosopher shows that the first active or moving principles of all things are the same but in relation to a certain order or rank. For first indeed are the principles without qualification incorruptible and immobile. There are, however, following on these, the incorruptible and mobile principles, to wit, the heavenly bodies, which by their motion cause generation and corruption in the world." In Bk. VII, lect. 6, no. 1403, in connection with the question of spontaneous generation, reference is similarly made " to the power of the heavens, which is the universal regulating power of generations and corruptions in these lower bodies. . . ."

For a full discussion, see Thomas Litt's study of Les Corps célestes dans I'univers de saint Thomas d'Aquin (Paris: Nauwelaerts, 1963), from the " Introduction " and " Conclusion" to which the following observations indicate the justice of my own allegations in this matter: " L'opinion courante, dans le monde des spécialistes de S. Thomas, est que la théorie des corps célestes reste parfaitement extrinsèque à l'enseignement philosophique ou théologique du saint docteur. Et ce qu'il y a d'étrange, c'est que cette opinion, non seulement est adoptée communement sans preuves, sans examen, mais qu'elle ne se formule même pas. Non seulement on escamote les corps célestes sans démontrer qu'on a le droit de les escamoter, mais on les escamote sans même le dire. . . ." (pp. 5-6) " Mais il y a au moins deux points de l'enseignement de S. Thomas où les corps célestes . . . entrent vraiment dans la doctrine elle-même, où, par conséquent, on altère ladite doctrine, si on les escamote . . . d'abord quant à la théorie de la matière et de la forme." (p. 6) Deuxièment, quant " à la doctrine des séries de causes subordonnées essentiellement." (p. 9) Mais aussi " il y a un troisième point où la théorie des corps célestes à eu une influence intime sur la doctrine philosophique de S. Thomas, et c'est, ni plus ni moins, la très générale et très fondamentale théorie de l'acte et de la puissance. L'univers de S. Thomas éta'it fait d'êtres qui passaient de la puissance à l'acte, c'est-à-dire, de l'imperfection à la perfection correspondant à leur espèce. . . . Ici encore, par consequent, une adaptation est nécessaire, si l'on veut transplanter la théorie de la puissance et de l'acte dans notre univers à nous." (pp. 11-12) " Les . . . chapitres de cet ouvrage montrent [que] ... la métaphysique "--ou bien, la cosmologie ou " scientia naturalis "--" des corps célestes . . . est incontestablement une pièce constitutive de la synthèse philosophique du Docteur commun et elle porte la marque de son genie propre: ses conceptions sur la nature et l'action des sphères célestes prennent place dans une vision grandiose de l'ordre universel; tous les aspects de cette cosmologie typiquement médiévale se complètent d'une manière rigoureusement cohérente et révèlent l'esprit de synthèse si caractéristique de la pensée du maitre." (p. 367) " La cosmologie des sphères célestes joue également un rôle dans la synthèse thèologique de S. Thomas." (p. 370) " Une . . . question, capitale pour les thomistes actuels, se pose aussitôt: le système philosophique de S. Thomas peut-il être amputé, sans inconvénient serieux, de la pseudo-métaphysique [pseudo-cosmologie] des sphères célestes? Ici une distinction importante s'impose. II est impossible de comprendre et d'exposer fidèlement le système élaboré par S. Thomas au XIII^e siècle en passant sous silence sa cosmologie céleste. . . . Mais le mouvement de renaissance thomiste ne peut pas être et ne veut pas être une restauration servile du thomisme médiéval. L'école thorniste contemporaine entend s'inspirer des enseignements du Docteur commun dans la mesure où ils s'avèrent capables de promouvoir l'essor d'une philosophie authentique, répondant aux requêtes de la pensée critique. Dans une telle entreprise, il est possible de reprendre à S. Thomas les thèses essentielles de sa métaphysique tout en sacrifiant les conceptions pseudo-métaphysiques et pseudo-scientifiques de sa 'physique céleste '. Celles-ci, en effet, sont des applications erronées ou imaginaires des principes métaphysiques, elles ne conditionnent pas ces principes.

" Mais il ne suffit pas de supprimer, il faut remplacer. Les philosophes thomistes d'aujourd'hui se trouvent devant la tâche redoutable de mettre sur pied une nouvelle cosmologie, une nouvelle philosophie de l'univers matériel, et notamment une reponse valable au problème de la finalité dans l'univers matériel en même temps qu'une épistémologie et une critique des sciences. L'oeuvre est à peine commencée. L'enquête qui s'achève ici montre combien cette oeuvre est nécessaire." (p. 372)

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spheres determined and governed the place and order of sublunary bodies, guaranteeing the rigid necessity and formal immutability of their natures, there could be no question of a speciation process altering across the ages the visible features of the natural world.

2) This socio-cultural background made it all but inevitable that the metaphysical notion of essence as a radical kind should be directly applied to all the natural kinds which are intuitively recognized, such as birds and fishes and oysters, even though each of these groups combines a multitude of differentiae and cannot be classified by a single difference as in a dichotomy; and even though, according to the metaphysical definition of an essential difference, things are constituted as distinct in kind only if they differ by a single ultimate difference or formal factor--differ the way traditional philosophy could distinguish only between corporeal, living, sensitive, and rational.

3) This equivocation in the application of " essence " to the natural kinds inevitably led to a focal reduction of ontology to logic, to the extent that it was necessary to predicate essential differences and thus to distinguish the species of nature not on the basis of properties in the strict sense but on the basis of a syndrome of accidents interpreted as extrinsic and empirical signs of the property convertible with the essence (see fn. 157 below).

4) Just as in order to maintain the equivocal use of the notion of essential kinds it became necessary to supplant the ontological notion of property by the logical notion, so as a result of this ambiguous criterion of specific differences the ontological problem about species (how many " essential" species or radical kinds are there?) entered into a circular interdependence with the epistemological problem (how many " essential" species or radical kinds do we know?) ,¹⁵⁵ For a long time this covert and unnatural symbiosis of ontology with logic went unnoticed;
it seemed to entail no more than the fact that our knowledge of nature is imperfect and that, so long as observing and thinking men are at work, there is always the possibility that new species may be discovered. But, as the

¹⁵⁵ See fn. 16 supra.

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investigation of nature progressed, it not only became clear that new species in the sense of natural kinds were there to be discovered, it also became clear that none of the natural kinds were fixed in form ¹⁵⁶ and that there was

¹⁵⁶ " Plaçons-nous maintenant au point de vue de la nature prise au sens strict de ' principium et causa motus et quietis ejus, in quo est primo et per se, et non secundum accidens.'--Natura determinata est ad unum. Voilà un principe donl on ne cesse d'abuser. On se fait d'habitude une idée trop homogène de la nature, comme si toute nature était egalement nature. Ne faudrait-il pas dire plutôt qu'il n'y a nature que dans la mesure où la matière et la forme sont déterminées? Si la forme avait d'elle-même une détermination parfaite, elle ne serait plus nature. Remarquons que nature se dit non seulement de la forme, mais aussi de la matière du composé." Charles De Koninck, " Réflexions sur le problème de l'indéterminisme," Revue Thomiste, XLIII (1937), pp. 236-7. See John of St. Thomas, Cursus Philosophicus, II, pp. 180 ff. (Reiser ed.).

This point is important and difficult enough to require a decisive clarification. Such is achieved, I think, in the following text from Adler, where in the form of objection and reply he is defending the view that there are a small number of ontological or essential species (radical kinds), definitely less than ten, against the objections raised by those of the view that there are a very large and undeterminate number of such species. The former Adler refers to as the " first position " or theory, the latter as the " second." (From The Problem of Species, pp. 195-8)

" Objection 4. In addition to those already cited (Obj. 3 contra 1) [see fn. 157 below], there are other well-attested facts which are difficult to explain according to the theory of the first position. The facts of procreation in the sphere of living things amply testify to the production of like by like. It is not simply that plants reproduce plants, and animals animals, but that this kind of plant uniformly tends to procreate organisms of the same kind, and similarly in the case of kinds of animals. Such uniformity in generation, furthermore, is connected with the aggregate of traits which constantly and peculiarly typify a kind of plant or animal; in other words, if a given kind is distinguished by an aggregate of traits found among all its members and only among them, the offspring will manifest the same traits in aggregate, and this is what is meant by like producing like. Thus, Monaco defines a species as ' a collection of individual living things which preserve the same powers and the same type through the generation of one from the other' (Praelectiones Metaphysicae Specialis, Pars II: de viventibus seu psychologia. Cap. I, Art. V, Th. XXIV; Rome, 1929, pp. 174-6); and his definition would hold for other accidents than power which, taken together, constitute the type.

" Now, it can be learned that Monaco and others, who take genetic uniformity as a sign of specificity, are right, by applying a fundamental principle to the facts cited. According to St. Thomas, ' the likeness of the begetter to the begotten is on account not of the matter, but of the form of the agent that generates its like' (Summa Theologica, I, 119, 2, ad 2). Furthermore, the substantial form is the, term of generation (i. e., substantial change). Hence to say that like generates like, in the reproduction of living things (Summa Theologica, I, 118, 1), is to say that the likeness between the begetter and the begotten must be in regard to substantial

no reason to believe that the syndrome of typifying traits by which the natural kinds could be classified were the

form. Wherefore we must conclude that if this kind of plant or animal generates its like in kind, i. e., if roses generate roses, and potatoes potatoes; if camels generate camels, and sparrows sparrows,--then all of these many kinds, which preserve their type throughout a series of generations, must be species. Otherwise, the term of generation would not be a substantial form, which is impossible. So it is shown that plant and animal are not infima species, but extensive genera including many specifically distinct kinds.

" Reply Obj. 4. Here as before the facts are readily admitted, but not the interpretation which the objection puts upon them. The interpretation is rejected for reasons which have already been made clear, namely, the role of signate matter in generation (Reply Obj. 3 contra 1). The signate matter, which is determinate not only in dimensions but in other accidental respects, is the source of racial and familial accidents, as well as individuating ones. Hence, the uniformities in biological reproduction are due partly to the substantial form, in so far as the offspring are like their ancestors in species, and partly to the signate matter, in so far as the progeny resemble their procreators in merely accidental respects.

" This will be seen at once if the facts are re-considered. There is uniformity in the generation of men of different races; thus, Caucasians generate Caucasians, and negroes negroes, if the breeding is restricted to individuals of the same stock. But we know that these are races, not species, and hence we must admit that this generation of like by like cannot mean that the term of generation is a substantial form, taken simply. It must rather be regarded as a substantial form (the principle of specific human nature) subject to further accidental determinations of a racial order. There is no more difficulty about this than that one individual should procreate another which is individually different because the substantial form which is alike in both begetter and begotten is, nevertheless, individuated differently in each, i. e., subject to further accidental determinations of an individuating sort. Nor need the begetter and the begotten always differ in their individual traits; they may also resemble each other in various accidental ways; but this cannot be due to their likeness in substantial form, since contingent accidents do not follow from the form. Hence it must be due to the condition of the signate matter in generation.

" In short, both racial and individual similarities between ancestors and progeny can be explained in the same way by reference to the role which signate matter plays in generation; in fact, they cannot be explained in any other way, because these similarities are with respect to contingent accidents, and they cannot be due to the substantial form. It does not follow, therefore, because roses generate roses, or camels camels, that these ' kinds ' are species. If there were other and independent evidence that rose was a species, there would be no need, of course, to have recourse to uniformity in generation to prove the point. But since such evidence is either lacking or not relevant, the facts of generation by themselves are totally insufficient because they can be, and must be, otherwise interpreted.

" The error which the objection makes is to suppose that form is always the principle of sameness and matter of difference; whereas, as we have seen (Reply Obj. 3 contra I), things may be specifically different in respect of form, and alike because of material accidents. And this applies also to the like and the unlike in the process of generation: matter, as signate, is the source of both differences and similarities of an accidental sort, whereas substantial form is the principle of essential sameness and distinction. Furthermore, the authority of St. Thomas in this connection may be disregarded, for what he says in the text cited is explained by his unavoidable ignorance of facts about generation which modern researches have discovered. In that same text (op. cit., I, 119, 2, ad 2), he writes: ' In order for a man to be like his grandfather, there is no need that the corporeal seminal matter should have been in the grandfather; but that there be in the semen a virtue derived from the soul of the grandfather through the father. . . . For kinship is not in relation to matter, but rather to the derivation of the forms.' But we know that there is a continuity in the germ plasm which is transmitted from generation to generation, as well, of course, as variability in its microscopic structure. It is, thus, in terms of the matter that relations of kinship are to be explained, and not simply through the derivation of forms. Both principles are required if we are to account for both specific nature and accidental traits, racial or individual, whether we are considering the similarities or the differences of living organisms. Error results from ignoring either principle, as the ancients from excusable ignorance neglected, in part at least, the contribution made by signate matter; and as some moderns from culpable neglect of philosophy, fail to take account of substantial form and hence either deny true species or else futilely seek to explain all uniformities in generation by reference to material dispositions.

" Finally it must be acknowledged that, in answering this objection and the previous one, we have presumed to speak about the nature of generation and the role of signate matter therein, without undertaking a complete analysis of these matters. The presumption seems justified, however, in the light of the traditional discussion of such problems."

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signs of a single specifying difference, of a property in the strictest ontological sense.¹⁵⁷

¹⁵⁷ This point is the very hinge of the issue. Its importance and the range of misunderstandings centered on it make it impossible to avoid citation in order to remove all equivocation and ambiguity in a decisive fashion. The text which achieves this is from Adler's early work on The Problem of Species, pp. 188-195; we shall cite only pp. 189-91.

" The fundamental error ... is a confusion of the logical and ontological meaning of ' property,' similar to the confusion of the logical and ontological meaning of ' species,' which has already been pointed out (vd. Obj. 5 contra II). Convertibility in predication is the logical criterion for calling an accidental term a property of a substance. The formula ' quod soli et semper et omni convenit ' merely states this criterion; this criterion or formula is a necessary, but not a sufficient, condition of something's being a property in a strictly ontological status. It is true that every accident which is a property is, in logical discourse, represented by a term convertibly predicable of its substantive subject; but not every term which is so predicable is ontologically a property. There are three other criteria, which must be satisfied: 1) The property of a substance must directly signify the substantial difference which cannot be directly apprehended; thus, rationality as a property signifies the substantial difference constitutive of human nature; 2) the property itself is never directly apprehended, but always known by the observation

At this point the problem was further vitiated by Darwin's denial not only that all or many of the natural kinds were distinct in the philosopher's sense of essentially or " radically " so but even distinct in kind at all. In other words, Darwin set up a three-sided issue in terms of a two-sided option: either the beings of nature differ in kind, or they differ only in degree, and specific distinctions are entirely of human making (quoad nos) . We have seen how subsequent researches in science proved Darwin wrong about the metalogical status of species and how subsequent analyses in philosophy proved him wrong about the modes of difference. We can extend this to much of what Adler says concerning the dispute about the uniqueness of man to the dispute about the nature of the difference between the living and the non-living and between plants and animals:

of other perceptible accidents, especially operations, actions or passions; 3) the property must not only follow necessarily from the substantial form, but it must be due to the form alone, and neither to the signate matter nor to the objective circumstances of the thing's existence or operation. By these three criteria, power and power alone can be the property of a substance. Not even the natural habits of a substance,--those constant and peculiar modifications of its powers which arise from its normal operations,--are properties. That risibility is traditionally said to be a property of man indicates how prevalent in the tradition is the confusion of logic and ontology; risibility, like the ability to speak grammatically, or to make things artistically, are certainly properties, in the logical sense; but when examined ontologically they are merely aspects of rationality in relation to the variety of objects with respect to which man operates. A sense of humor and grammatical speech are ' natural arts ' of man, constant and peculiar modifications of his rational powers functioning, as they must, in cooperation with sense and other bodily powers. If these are not powers, and hence not properties, how much less so are modes of operation which depend merely upon peculiarities of bodily arrangement or objective circumstance; and even less are such things as figure, color, duration, place, etc. For all these are directly observable accidents; they obviously do not follow from the substantial form alone; nor do they signify a substantial difference directly, as the intellectual powers of man, the proper accident of human nature, signify rationality, as the substantial difference, united with animality, as the generic nature, in the constitution of the human essence. Although we have discussed the essence and property of man, because the second position admits man to be an infima species, what has been said here applies universally to the relation of essence and property. Therefore, we must conclude that none of the so-called constant and peculiar accidents mentioned in the objection are properties (necessary or proper accidents). They are all contingent or adventitious accidents."

Most, if not all [modern authors] have approached the question with too few distinctions explicitly in mind. They use the words " degree " and " kind " without qualifying them by such critical modifiers as " real " and " apparent," " superficial " and " radical." The reader will find that the philosophical and scientific literature on the subject of man's difference is simply not intelligible without these distinctions, especially the distinction between a radical and a superficial difference in kind.¹⁵⁸

Yet in fact traditional philosophy and evolutionary science are generally considered to be antipathetic, notwithstanding this double advance. Here we are at the fourth and principal source of the still prevailing ambiguities and uncertainties surrounding the traditional notion of species as essentially distinct kinds: what started out in ancient times as a temporary dependence in ontology upon logical criteria for the determination of species, ended up in modern times as an abandonment of the principle of parsimony in the analysis of natural kinds. I think that when and if the history of neo-scholasticism is written, it will have at its disposal in the writings of Maritain, Garrigou-Lagrange, Rousselot, Gredt, Brennan, Maquart, and Phillips so far as they treat of species a classic illustration of the ancient adage, parvus error in principio magnus est in fine--a small initial mistake is a colossal error in the end.^158a

If it is true that no theoretical constructs should be resorted to that can be dispensed with in explaining the phenomena, and if there is no evidence that any of the natural kinds recognized as species by modern biology exhibit the " infima specific " construction of traditional philosophy, then, by the stated principle which obliges us to judge in the light of the available evidence, we are

¹⁵⁸ Adler, The Difference of Man, p. 32.

^158a St. Thomas, De ente et essentia, " Prooemium." See also Aristotle, De caelo, I, c. 5, 271b8-13; St. Thomas, In I de caelo, lect. 9, n. 97. Averroes has the clearest formulation, In III de anima, cap. IV, Lyons 1542 in 16, f. 112^V, comm. 4: " minimus enim error in principio, est causa maximi erroris in fine, sicut dicit Aristoteles."

forced to acknowledge that the metaphysical analysis of essence as constituted by a genus together with a unitary formal difference cannot be applied directly to the diversity and hierarchy of natural kinds so far as they are constituted by groups discriminable as such only by virtue of a syndrome of observable traits, so far, that is, as they are constituted by groups which " we must define at the outset by a multiplicity of differentiae." ¹⁵⁹

The alternative, to whatever extent the principle is abandoned, is to engage in myth making. The point is that, in the present state of evidence, it is impossible to simultaneously respect the regulation of the principle of parsimony and appeal to principles proper to epistemology on questions concerning the metalogical (ontological) status and number of the radical kinds of being. This was illustrated in the famous distinction scholastics drew between " natural " and " systematic " species (Maritain speaks of " the ontological species, not the taxonomic species dealt with in botany, zoology or genetics " ¹⁶⁰):

Three things must be distinguished: a) varieties (races); b) types now sharply distinct within the same species, i. e., systematic species; c) natural species. . . . The stability of systematic species is only relative; of the natural species, absolute. Nor can there be so much diversity introduced into the natural species through the systematic species as would obliterate their specific type, i. e., their specific organization. The only difficulty now is to discriminate between the natural and the systematic species. ... It is clear that we must consider brutes and plants as supreme genera, which are further divided into diverse natural genera and species. It belongs to biology, however, not philosophy, to determine what these genera and species are.¹⁶¹

¹⁵⁹ Aristotle, De partibus animalium, Bk. I, ch. 3, 643 b 25.

¹⁶⁰ Jacques Maritain, " Substantial Forms and Evolution," in The Range of Reason, p. 37.

¹⁶¹ Josephus Gredt, Elementa Philosophiae Aristotelico-Thomisticae, editio decima tertia recognita et aucta ab Euchario Zenzen (Barcelona: Herder, 1961), n. 611, p. 541. It should be noted here, however, first, how close Gredt's " tria distinguenda " are to the notions of apparent, superficial, and radical kinds; second, that since Gredt's time, the great advances in the knowledge of heredity and in the analysis of the genetic code (DNA/RNA) have seriously undermined the foundation on which Gredt rested his entire argument: " Ex organisatione stricte essentiali, quae rationem habet proprii stricte (quod soli et semper et omni convenit [notice here the confusion uncovered in fn. 157 supra between the logical and ontological meaning of property], cum certitudine cognosci possent omnes species naturales. Sed haec organisatio nos latet; consistit enim in ilia microorganisatione, quae jam habetur in cellula germinali (fecundata), unde incipit evolutio viventis(cf. n. 406; 449; 452, 2). Cum incipit evolutio viventis, anima seu forma substantialis specifica viventis jam adest, quae essentialiter concectitur cum hace microorganisatione. Haec enim microorganisatio est dispositio proxima ad eam. Evolutione viventis, quae divisione cellularum fit, haec dispositio stricte essentialis communicatur cum diversis cellulis. Sed haec microorganisatio fugit etiam investigationem microscopicam. Necesse est igitur discamus essentiales corporum viventium differentias ex typo externo, ex proprietatibus, quae in individuo vivente in decursu evolutionis suae extrinsecus apparet, ut jam indicavimus. . . ." What has already been discussed in sections IV and V above justifies, I think, the contention that, if one grants the validity of Gredt's premises here, then it is necessary in the light of now available evidence to draw from them conclusions not compatible with what Gredt himself contended. See the remark of Maritain cited in fn. 163 below.

Such a conception is truly a curio of history, inasmuch as it predates the " family quarrel' between Linnaeus and Darwin. Such a conception also belongs to the class of entia multiplicanda sine necessitate, of myth in the philosophical sense, inasmuch as the mass of data gathered in both the paleo- and neo-sciences favors a denial of these " natural species." Such a conception dialectically belongs to the order of non-argument, inasmuch as it posits an ontological distinction which it admits cannot be verified in a single known case and defends the validity of the distinction on the grounds of our ignorance, thus making the ontological problem a function of the epistemological problem.¹⁶² Finally, such a conception contradicts itself;

¹⁶² The confusion of logic and ontology in the Aristotelian-Thomistic species problematic perhaps reached its greatest depth at the time that Gredt could write (a passage not edited, be it noted, as late as 1961 in Zenzen's edition): " Evolutionismus ille, qui rerum distinctionem specificam tollit (darwinismus), arborem Porphyrii destruit" (op. cit., n. 160, p. 143). As Adler early pointed out, " the famous Tree is not purely a logical representation of the arrangement of concepts, but a confusion of logical with ontological ordering. Wherever the philosophical tradition has followed or been influenced by Porphyry, this confusion appears." Not only is " the error a characteristic consequence of the platonizing of Aristotelian science," but " one wonders whether the confusion of logic and ontology in the Porphyrian tradition is also a confusion of the orders of substance and accident." (The Problem of Species, p. 68 fn. 86, p. 70, respectively), See The Problem of Species, pp. 64-70. These pages must be read, however, in the light of the rectified theory of an ontological common genus as presented in " Solution of the Problem of Species "; and in this latter work, see also the " Historical Hypothesis," pp. 360-378, which essays to circumscribe in the Aristotelian writings the root sources of the ambiguities and uncertainties which have plagued the philosophical species problematic from the beginning.

See also Maritain's non-argument that " the true character of matter demands " that we should not be able to know, by essential definitions, any specific natures inferior to man (" Preface " to The Problem of Species, p. x), which objection is thoroughly rebutted by Adler in " Solution of the Problem of Species," pp. 345-50.

for the philosopher who entertains it, " while confessing his dependence on the scientist for knowledge of distinctions below plant and brute, he transgresses the sphere of his competence--violating the autonomy of science--by deciding what scientific evidence he will accept or reject." ^l63 What Mortimer Adler noticed in this regard thirty years ago, curiously, continues to be true today: " The problems which result from such errors and transgressions are false and ungenuine; yet, for the most part, these are the matters discussed when philosophers and scientists engage in controversy about evolution.' " ¹⁶⁴

¹⁶³ Adler, The Problem of Species, p. 269. Here then one may cite Maritain contre lui-même: " Given that philosophy is in its own right independent of the sciences . . . nevertheless . . . the sciences may indirectly reveal the falsity of this or that philosophical doctrine . . . if and. when a philosophical doctrine happens to encroach upon science itself or to have, as a necessary consequence, a certain scientific conception, or rather a certain general framework imposed on science, whose emptiness is demonstrated." (The Degrees of Knowledge, p. 59, my emphasis). Such has almost certainly been the case with the traditional philosophical doctrine of the infima species.

¹⁶⁴ Ibid. And sometimes these pseudo-problems underlie the discussion of larger matters as well. For example, I think that Maritain's way of subdividing " empiriological knowledge of nature " into " empiriometric " and " empirioschematic " can be shown to depend in part on the position he adopts over the issue of the number and constitution of specific natures (e. g., see The Degrees of Knowledge, pp. 30-50, esp. pp. 31, 38, and 45; pp. 173-181, esp. p. 176 fn. 2, pp. 176-8, esp. p. 178; p. 205 text and fn. 1, pp. 206-9). Thus the philosophical dimensions of the problem of species have a definite bearing on the philosophy of science; and moreover, once the necessary corrections in the formulation of the species problematic have been achieved, I think it is possible to formulate a solution to the problem of the distinction and relations between science and philosophy which not only meets the requirements of the problem on both sides, but which also reconciles the views of Ashley, Adler, and Maritain in a higher synthesis (formaliter eminenter) to which each of them could give unqualified assent. This, of course, would have to be shown, for it constitutes a study in its own right.

5) Inescapably linked with the question of specific transformations is the problem of the assignation of causes. To some philosophers, the possibility of individuals giving rise to more perfect individuals seems a violation of the necessary proportion between cause and effect. We shall return to this in a later Section (VIII).

6) The two final sources of ambiguity and uncertainty in the traditional species problematic are closely linked. The philosophical tradition of Aristotle became in St. Thomas a theological tradition as well. The static view of natural kinds, originally rooted in the immutable heavens, seemed to the theologians of medieval times to be indicated in the scriptural texts as well, at least to the extent that the origin of any new specific form was an event involving a special divine creative act. In this way the immutability of specific natures came to mean that
the individuals of one species " cannot be generated by or generate [individuals of] another species through the operation of secondary causes alone." ¹⁶⁵

7) The final source of difficulty is a psychological one. Whatever one may think about a science, the architectural structure of which is authority and the foundation of which a text, it is not a mode of knowledge foreign to human nature. Man is by nature an authority acceptor as well as a reasoner.^165a  It is impossible to admit the

¹⁶⁵ See Adler, The Problem of Species, pp. 202, 221, 228 fn. 110, 229-30, 251 et alibi. In fn. 110, p. 228, Adler wrote: " in the first occurrence of any new species, Divine causality must intervene," since generation by equivocal causality would be " impossible." (Although in fn. 285 on p. 275 he quotes De Koninck approvingly as saying that " when a superior nature is produced from the potency of an inferior nature by equivocal generation, this production remains natural.") From a recent telephone conversation, however, I am glad to say that he now is in agreement with the view that will be expressed in Section VIII below, namely, that it is impossible to demonstrate the impossibility in any case of the origin of an (ontologically) higher material form from an (ontologically) lower causal series, by reason of the reciprocal repercussion of the causes.

^165a See C. H. Waddington's important study of man as The Ethical Animal (Atheneum, 1960). Thus, not only in the matter of specific natures but in a great many other problem areas as well, " Thomists, in principle, state that one should not rest on authority in matters philosophical, and yet de facto they have been doing precisely this," observes William A. Wallace in an article on " Thomism and Modern Science," The Thomist, XXXII (January, 1968), pp. 82-83.

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natural origin of the natural species and reconcile all the traditional texts with the admission.¹⁶⁶

Such then are seven of the major sources of ambivalence and equivocation in the traditional problematic of species: the notion of an unchanging causa regitiva keeping the relation of generator to generated within fixed limits; an insufficiently critical appraisal of the order of natural kinds in the light of the metaphysics of essential constitution; an abandonment of the autonomy of ontological principles in the effort to systematize the diversity of nature in terms of morphology; a partial abandonment in the face of evolutionary data of the methodological principle of parsimony; a tendency to conceive of causal interrelations reductively rather than factorially; the theological argument that God " intervened " at the origin of every species; a respect for authority which has blunted the thrust of much of the traditional analyses. It is their cumulative and mutually reinforcing effect that is denoted in the expression, " the error of univocally ontologized kind-essences."

No one, in my reading, has better summarized the current and long-standing failure of traditional philosophy and contemporary biology to communicate in the area of species--notwithstanding their common logic and common set of questions, formally speaking--than has Raymond Nogar.¹⁶⁷ In a symposium on The Species Problem (1957), Nogar notes, Ernst Mayr, the editor, deplored the wide variety of species concepts and says:

I believe that the analysis of the species problem would be considerably advanced if we could penetrate through such empirical terms as phenotypic, morphological, genetic, phylogenetic, or biological to

¹⁶⁶ For example, it does not seem possible to save all the theological texts of Aquinas if one admits that natural origin--i. e., origin in which the proportioned operation of secondary causes is undisturbed--applies below man even in the case of beings which differ in grades of being as well as in degrees of perfection. See The Problem of Species, pp. 226-30.

¹⁶⁷ In The Wisdom of Evolution, pp. 328-30.

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the underlying philosophical concepts. A deep and perhaps widening gulf has existed in recent decades between philosophy and empirical biology. It seems that the species problem is a topic where productive collaboration between the two fields is possible.¹⁶⁸

Commenting on this text, Nogar considers Mayr's position to be perfectly correct. He then points out the obstacle to such collaboration that must first be overcome:

But the difficulty with the species problem is that the biologist and the philosopher are usually looking for different things. Hence the difference in the meaning of terms. The biologist is seeking a workable field definition of species which will enable him to classify all animals and plants. The philosopher, on the other hand, has been attempting to find a sic et non division of cosmic reality which will, by a single characteristic, manifest what a given natural species is and how it differs from every other natural species.¹⁶⁹

The indispensable step, therefore, in achieving the collaboration Mayr calls for is that the philosopher put aside for the moment his preoccupation with discriminating between irreducible grades of being, in order to attend to the genetic and causal explanation of natural kinds secured by modern evolutionary science. At the level of individual substances as members of adaptive populations structured intrinsically through interaction, what are the " underlying philosophical concepts "? What is the ontological status of species so considered?

The question is proper and possible inasmuch as the ontological order bases all modes reality takes at every existential level. It is necessary if the real nature of Darwin's influence on philosophy is to be made explicit. And it is a distinctively contemporary question inasmuch as its answer is the basis for

¹⁶⁸ Ernst Mayr, The Species Problem (Washington: American Association for the Advancement of Science, 1957), p. 11.

¹⁶⁹ The Wisdom, of Evolution, p. 328: " The latter group has followed, in the main, the lead of the logician or dialectician who attempts to view things in their ideal perfections. The logician uses as his model the logical instrument invented in the early centuries called the Porphyrian tree after the Greek neo-Platonist Porphyry (A. D. 233-304). By means of this classic diagram, the world of reality is arranged according to an ideal bipartite division of being.

" It has been shown in great detail that nature and natural species cannot be viewed with this perfect logical or dialectical arrangement."

the prior possibility of integrating through their respective ramifications the traditional and contemporary species problematics.

It is useful in seeking to come to terms with this question to place ourselves explicitly in the evolutionary context, that is to say, in the context of history as structured causally, in order to bypass for now the preoccupation of certain temperaments with projecting the disproportion formally involved in the causal succession of complex from simple beings, and with introducing God into the development of nature.

The configuration of the living, as of any other, world depends from instant to instant on its last previous configuration and on how the immanent processes, the " laws " of nature, tend to act on any given configuration. Involved is historical causation, which includes everything that has ever happened and which is thus an inherently nonrepeatable accumulation. In application to evolution, these rather abstract considerations mean that the actual course of evolution is determined not only by its processes but also by the cumulative total of all previous events.¹⁷⁰

Just as in the traditional problematic of species, so in this one, the philosophical problems raised by the causality involved resolve radically into the question of the reality or meaning behind the term essence (essentia) --but with a difference. In the traditional problematic, the species " has only intentional being, except as a constituent in the individual nature, through which it, too, participates in the act of existence," ¹⁷¹ inasmuch as the species " is that essence which can receive no further determinations except those of individuation." ¹⁷² " From this it will be clear that the word ' species,' " as used in the traditional problematic, " never refers to an existent thing, for in the domain of material beings only individuals exist, and never species." ¹⁷³

¹⁷⁰ George Gaylord Simpson, " The Study of Evolution: Methods and Present Status of Theory," in Behavior and Evolution, edited by Anne Roe and George Gaylord Simpson (New Haven: Yale, 1958), pp. 21-2.

¹⁷¹Adler, The Problem of Species, p. 19.

¹⁷² Ibid., p. 18.

¹⁷³ Ibid., p. 14. See p. 88 of Simon, The Tradition of Natural Law (New York: Fordham, 1965), middle paragraph.

When we speak of two substances as belonging to the same species, we mean that they communicate in the same specific nature, though, of course, what is common to them is not identically the same in both, because the specific nature is differently individuated in each, according to the individual differences which constitute their twoness or numerical diversity. The specific nature they share in common is the same only in the sense indicated by the fact that a third substance of different species would differ specifically as well as individually from the two things first considered. The specific nature of the third would be different. In short, the fact that a specific nature can exist in its purity, i. e., in its absolute unity apart from individual multiplications and differentiations, in its unrestricted universality, only in an intellect which abstracts the form from the individuating conditions of matter, does not mean that " species " signifies only the concept (second intention) rather than that which is conceived (first intention). That which is conceived is the specific nature as an ontological principle, commonly present in a number of individuals which are truly apprehended as belonging to the same species. The potential universality of the specific nature,--a potentiality actualized only by intellectual abstraction,--is identical with the actual commonness of the nature as participated in by a number of individuals. Although apart from the mind, the specific natures of composite substances do not exist as universals, they do exist commonly,--i. e., as the same nature in two or more individuals,--and this fact is the ontological counterpart of the universality of the idea achieved by abstraction.¹⁷⁴

In this new problematic, by contrast, " the species is constituted by a substance incorporated in a mass," and " the masses formed by these substances are not unitary entities but collective ones,"¹⁷⁵ functioning entirely independently of our mental constructs in patterns of distribution conditioned by ecology or geography.

This indicates at once the altered sense of the term " essence " as it occurs in the two problematics: " If the word ' essence' be used to signify what is the proximate subject of the act of existence, then, in the case of composite substances,

¹⁷⁴ Ibid., p. 13. See also John V. Bums, "The Problem of Specific Natures," The New Scholasticism, XXX (July, 1956), pp. 286-309.

¹⁷⁵ Beaudry, art. cit., p. 225.

essence as the subject of existence must be the individual nature rather than the specific nature." ¹⁷⁶ At the same time it also indicates, from the traditional viewpoint, the fundamental reason why species in the second or modern sense do not constitute an arbitrary schema nor circumscribe a reality too dark to be illumined in a properly ontological way: since, " in the case of composite substances, essence as the quiddity or principle of intelligibility, and essence as the proximate subject of existence, are not the same nature " ¹⁷⁷ (the former being but potentially individuated, the latter actually so), and since in the case of natural populations " the distinctness of the individuals does not destroy the reality of the mass " ¹⁷⁸ or " natural grouping," it stands out clearly that " the proper task for the philosopher, with respect to evolution, is primarily the analysis of the principles of substantial change, as bearing on the production of the unlike, both accidentally," or with respect to the diversification of superficial kinds, " and essentially," or with respect to the establishment of the radical kinds, " in the process of procreation." ¹⁷⁹ Inasmuch as the latter is possible only in the light of the former, however, it is clear both that and how the two problematics require interarticulation, and it is just at that point that the celebrated " influence of Darwinism on philosophy " is felt.

This will suffice to indicate why and in what sense a hylomorphic analysis of the structure of interaction in terms of what can be said at the level of existence exercised and prior to any analysis of the pure line of essence taken in itself (whereon alone arise the questions about the constitution, order, and number of radically distinct kinds) is the region of mediation between the primary concerns of the differently oriented species problematics of traditional philosophy and contemporary science. We may turn at once to the delineation of this region.

¹⁷⁶ Adler, The Problem of Species, p. 18.

¹⁷⁷ Ibid., fn. 6, p. 18.

¹⁷⁸ Beaudry, p. 225.

¹⁷⁹ The Problem of Species, p. 274, fn. 284. See fns. 156 and 157 supra.

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That which makes a thing to be what it is, or, more precisely, that by which a thing is such a thing as it is ("id quo ens est tale "), is said to be its essence.¹⁸⁰ Such a characterization, however, never signifies at the level of first intention (of " the organism as a describable object") a class of objects, but rather does it signify essence as the inward condition of the fact of this concrete existent. Here then, for our purposes, is the starting point from which alone must be determined the primary meaning of essentia, i. e., the meaning to which all other essentialist notions must be derivatively referred. Precisely in attaining explicitly to this determination can we effect the destruction of essence as a specific kind-concept of univocal predication, thus clearing the way for the authentic influence of Darwin on philosophy and removing the obstacle to productive collaboration between modern biology and traditional philosophy at a single stroke.

Historically, we have already indicated a number of critical considerations relevant to this line of inquiry; without pretending to develop thoroughly the analysis required to complete the proposed destruction, we can sketch at least in an indicative, preliminary way the lines which it must follow if it is to be carried through successfully.

¹⁸⁰ ". . . it is things, subjects, existents that we experience. From these existents our intelligence disengages by abstraction essences--' suchnesses' or intelligible ' structures'. These are the object of its first operation (simple apprehension) and of eidetic vision. Though these essences are found in a state of universality in our mind, where they are known as such, they exist really in things--in a state of singularity, as individual natures. To deny or to put in doubt this extramental reality of (individuated) essences would be to put in doubt the noetic value of the human intelligence. But for a sufficiently attentive analysis what is the absolutely precise and ' pure' data of the intelligence as far as essences are concerned? Because they are derived from existents by the operation of the intelligence, they do not appear as the existents themselves made present to us, but quite precisely as something immanent in the existents and which determine the existents to be what they are. The intelligence seizes them and gives them to us as that by which the things, subjects, or existents, are such or such. Hence, in its very notion, essence is a principle quo." Jacques Maritain The Degrees of Knowledge, pp. 435-6. Cf. A. G. Van Melsen, The Philosophy of Nature (Pittsburgh: Duquesne, 1961), " The Species--Individual Structure of Matter," pp. 115-125.

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Fundamentally, the question evolution poses in terms of our understanding of essence is the question of being-as-possible: Essence within this existent as a subject capable of existing-actualized points to the question of how was this essence actualizable? What was its pre-subjective reality as such?

Here we must realize at once that in applying the concept of possibility at the level of essence so considered we make a transcendental transference, so that the meaning of our term becomes simply different from what it denoted at the existential level. We cannot ask about possible essences as such in terms of a determinate positive content, not even by limiting such a content to intelligibly prejacent " essential notes." In other words, in itself, essentia, as the capacity to be, cannot be conceptualized: as a potentiality or subject " out of which " and considered apart from actual existence or " esse," the word essence retains no intelligible content.

It is necessary to repeat in this connection that we are making no statement here concerning " the line of essence considered in itself," i. e., as an a priori of historical causation, which, precisely as a purely eidetic consideration, would pertain most properly to considerations of second intention (i. e., to phenomenological research and to logic), or derivatively and as a constitutional question, or question of formal intelligible constituent sine qua non, to metaphysics; we address ourselves rather and with full reflexive restriction to structured exercise of existence which is exactly the meaning of " essence " in terms directly and immediately of first intention.

It is for this very reason that our concern shares the intentional content of the traditional efforts at an elaboration of the sense of subsistere: " if existence is seized by the essence as act by potency, it is by (the existence) itself holding (not certainly [through] efficient causality, but by formal or intrinsically activating causality) the essence outside the realm of simple possibility, since the esse is not received by the essence as in a pre-existing subject which would thus already be in existential act. The essence which receives existence holds from it--in what concerns the existential order--absolutely all its

actuality, in short is nothing without it";¹⁸¹ from which it must be inferred that " since existence is by its very notion an exercised act, the essence can be so held outside the realm of simple possibility only on condition of being at the same time carried by subsistence to the state of subject or supposit capable of exercising existence." ¹⁸² Hence the conclusion: " the proper effect of subsistence ... is simply . . . the promotion onto a new plane of the incommunicability which defines singularity."¹⁸³

It is not therefore just a matter of one metaphysical dimension in the structure of being but of the primordial dimension enclosing all others. By attempting to place ourselves ontologically at the level of natural kinds as such existing in order to " penetrate through such empirical terms as phenotypic, morphological, genetic, phylogenetic, or biological to the underlying philosophical concepts," we find ourselves at one and the same time located outside the order of essence considered in itself (the order of intelligible a priori for the possibility of a material order of being) and within a region of shared concern constituted by the pattern of interimplications between the traditional and the modem problematic of species, but a region

¹⁸¹ Jacques Maritain, " On the Notion of Subsistence: Further Elucidations," in Appendix IV to The Degrees of Knowledge, p. 437.

¹⁸² Ibid., p. 438.

¹⁸³ Ibid.: " And so the proper effect of subsistence is not ... to confer on the individuated essence or individual nature an additional incommunicability (this time in relation to existence) or to make it limit, appropriate, or circumscribe to itself the existence it received, and hence prevent its communicating in existence with another essence or receiving existence conjointly with another essence: it is simply to place it in a state of exercising existence, with the incommunicability proper to the individual nature. The individual nature does not receive a new incommunicability from the fact of subsistence. Facing existence as a subject or supposit capable of exercising existence, it is enabled to transfer it into the existential order, to exercise in existence itself the incommunicability which characterizes it in the order of essence and as an individual nature distinct from any other. This is not a new kind of incommunicability, but the promotion onto a new plane of the incommunicability which defines singularity. Subsistence renders the essence (become supposit) capable of existing per se separatim (cf. Summa, III, q. 2, a. 2 ad 3), because it renders an individual nature (become supposit) capable of exercising existence."

till now undisclosed as shared from the standpoint of the primary concerns of either problematic. Herein we may suspect is a crucial area wherein not only are the evolutionary species reduced to their underlying ground of intelligible possibility but wherein also careful reflection upon the data of evolution opens the way to a decisive reformulation of a question " disputata inter doctores " for literally centuries. And just as the value of this former penetration frees the proper influence of Darwin on philosophy (an influence altogether different from what Dewey envisaged " in anticipating the direction of the transformations in philosophy to be wrought by the [putatively] Darwinian genetic and experimental logic " ¹⁸⁴), so is the value of this latter reformulation inestimable to the Aristotelian philosophical tradition, for all will agree that--de jure at least-- " a problem (not a mystery) is the one thing which should not be perennial in philosophia perennis." ¹⁸⁵

It appears, then, that subsistence constitutes a new metaphysical dimension, a positive actuation or perfection, but under the title of a state (according as a " state " is distinguished from a " nature " [i. e., specific nature au sens traditionelle]).... Let us say that the state in question is a state of active exercise, which by that very fact makes the essence pass beyond the order of essentiality (terminates it in this sense) and introduces it into the existential order--a state by reason of which the essence so completed faces existence not in order only to receive it, but to exercise it, and constitute henceforth a centre of existential and operative activity, a subject or supposit which exercises at once the substantial esse proper to it and the diverse accidental esse proper to the operation which it produces by its power or faculties.¹⁸⁶

¹⁸⁴ Dewey, " The Influence of Darwinism on Philosophy," p. 18.

¹⁸⁵ Adler, "Solution of the Problem of Species," p. 341.

¹⁸⁶ Maritain, " On the Notion of Subsistence," p. 438. See Etienne Gilson, Being and Some Philosophers (2nd ed., corrected and enlarged; Toronto: Pontifical Institute, 1952), p. 183: " Finite essences always entail both limitation and determination, because each of them is the formal delimitation of a possible being. Yet, if such a possible essence actually receives existence, it is a being, owing to its own act of existing, so that, even in the order of finite being, the primacy of existence still obtains. Its act of existing is what insures the unity of the thing. Matter, form, substance, accidents, operations, everything in it directly or indirectly shares in one and the same act of existing. And this is why the thing is both being and one. Existence is not what keeps elements apart, it is what blends them together as constituent elements of the same being. For the same reason, temporal existence is neither the ceaseless breaking up of eternity nor the perpetual parceling out of being; it is rather their progressive achievement through becoming."

Gilson considers that " this intrinsic dynamism of being necessarily entails a radical transformation of the Aristotelian conception of essences," inasmuch as Aristotle's metaphysics was a " dynamism of the form," deepened in its own line by Aquinas into a " dynamism of esse (to be)." ¹⁸⁷ That indeed is why (there are theological reasons as well, but they are irrelevant for this context) subsistentia is a problem distinctive of Thomistic metaphysics. But it is extravagant, in my estimation, to say that with this development of a tradition in its own line " the whole philosophical outlook on reality at once became different." ¹⁸⁸ And in the second place, so far as the

¹⁸⁷ Gilson, Being and Some Philosophers, p. 185. See the discussion in footnote188 below.

¹⁸⁸ Ibid. Extravagant declarations by historians in philosophy have the decided tendency of transforming themselves in the minds of their hearers into doctrinal positions sure of themselves and of their power to renew everything. Such has been the distinct tendency among certain of the disciples of Gilson, who, seizing upon the " dynamism of esse," no longer hesitate to conjecture the next step in " the direction in which the history and science of metaphysics will develop" (W. E. Carlo, The Ultimate Reducibility of Essence to Existence in Existential
Metaphysics [The Hague: Martinus Nijhoff, 1966], p. 3).

So far as the history of metaphysics is concerned, the reduction of essence to existence may well mark the metaphysical writings of prominent authors, and if so, the " whole philosophical outlook on reality " does indeed become different; and we find ourselves, by an unexpected turn of history, re-established within a Suarezian metaphysics, this time " turned on its head," so that existence is no longer reduced to essence in the denial of their real distinction, but the reverse (much what happened to Hegel at the hands of Marx).

So far as the science of metaphysics is concerned, however, the primacy of esse over essentia which recognizes itself in Thomas for the first time clearly is exactly a clearer realization for philosophy of the principle of the primacy of act over potency, secured now at the level of existential act. It is in this sense and this sense alone that the Aristotelian " dynamism of form" becomes with Thomas a " dynamism of esse"; and between the doctrine of the ultimate subordination of essence to existence and that of the ultimate reducibility of the former to the latter lies all the difference between philosophical progress by way of development and philosophical progress by way of substitution. Fr. Gredt has stated the final reason for the possibility of conceiving philosophical progress in the former manner in lines which leave nothing to be desired in point of exactitude, and which have the further merit of bounding definitively the doctrinal sense of historians' proclamations concerning the transformations of the philosophical landscape one discovers (and they are there) in reading Aristotle through the Commentaria and Summae of Aquinas: " Philosophia aristotelico-thomistica essentialiter consistit in evolutione rigorose logica et consequenti doctrinae aristotelicae de potentia et actu. Haec doctrina ab Aristotele proposita, a S. Thoma declarata et ulterius evoluta, in schola thomistica iterum iterumque elaborata est et contra adversariorum impugnationes defensa. Fundameutum eius est distinctio realis inter actum et potentiam limitantem actum: inter essentiam limitantem esse et materiam limitantem formam. Esse irreceptum est simpliciter infinitum, actus purus; et forma pure spiritualis, in nulla materia receptibilis, est in sua linea infinita. Quo stabilitur distinctio inter Deum et mundum, inter mundum spiritualem et corporeum. . . . philosophiam aristotelico-thomisticam doctrinam ex hoc fundamento logica consequentia evolutam," ostendibile est. (J. Gredt, " Introductio" in Elementa Philosophiae Aristotelico-Thomisticae, Vol. I, p. 5, n. 3. See in this same line the instructive article by C. Fabro, " Tommaso d'Aquino," in Enciclopedia Cattolica, Vol. XII [Florence, 1954], cols. 259-265.) But then, everyone knows that Fr. Gredt is one of the " manualistae": see Jacques Maritain's remarks on " The Philosophy of St. Thomas " in The Peasant of the Garonne (New York: Holt, Rinehart, & Winston, 1968), pp. 135-141.

The point remains that one may have " progress " in philosophical history by substitution, by a discontinuous jumping between the fundamental dialectical options or " logical possibilities" envisionable in terms of a basic philosophical problem; but in the history of a doctrine (something else than a school), such " progress" has more of the character of a series of betrayals or abandonings, whatever may be the doctrinal position from which one views the movement. And one may quite well leave aside the language of the " real distinction" (esse/ essentia), still more the " texts " from whosesoever pen, without turning one's gaze from the matter-at-issue: what is the character of the difference between act and potency, and what does this imply in the order of lived experience for existence exercised?

See further fn. 196 below.

Aristotelian conception of essences was involved in the problem of specific natures, it neither was nor could be " radically transformed " without the whole problem of the metaphysical grades of being being abandoned. There is no doubt that, as Mortimer Adler has so carefully exhibited, this St. Thomas did not do. If he had done so, the " traditional" species problematic would not be distinguishable from the modern one in its primary concern. For St. Thomas, as for Aristotle, the notion of species was convertible with the usual use of essence and belonged to the ontology of natural kinds by way of secondary employment.

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What is true is that the distinctive advance of St. Thomas over Aristotle in having recognized the transcendence of existence respecting essence makes it possible to see the repercussions of evolutionary species on the question of the hierarchy of being according to essential grades. But, without further historical digression, let us resume the thread of our analysis.

As we noted initially, a strict employment of the term essence is possible which confines us to the concrete real, the historical reality as reality, and refers simply to the capacity to be as a self-identity. The whole of that which constitutes a capacity to be, however, must include what is necessary, i. e., whatever is intrinsic: and since only individuals do or can exist, individuating characters are radically enclosed at the level of essence, not as " accidental " (per accidens) modifications but as intrinsic and absolute substantial modalities. The total " capacity to be" in every instance is not merely " forma substantialis " but " matter-form," or, more exactly (for this is what forma substantialis is), materia actuata, i. e., all individuating notes or modalities. " It is evident that every natural generation involves a measure of uncertainty. If that uncertainty could be entirely eliminated, it would be because the form would be entirely determined--but in that case generation itself would become impossible." ¹⁸⁹ Since it is at the heart of being, this " incertitude " bears equally on the existence of the effect or product and on its very structure.

It is precisely the lack of determination of natural forms and their incapacity for individuating themselves which makes matter necessary for their existence. This necessity for matter introduces into the form itself an irreducible obscurity. There can be no idea of a cosmic form that is distinct and independent from the idea of the composite; ¹⁹⁰ and the matter which enters into this idea is not determined at all without signifying also a determinability with respect to an infinity of other forms. A non-subsistent form is not a quiddity in the strict sense.¹⁹¹ This means that the different

¹⁸⁹ De Koninck, " Refléxions sur le problème de l'indéterminisme," p. 238.

¹⁹⁰ John of St. Thomas, Cursus Theologicus, II, p. 575, n. 15.

¹⁹¹ "Anima sensibilis cum non sit res subsistens, non est quidditas, sicut nec aliae formae materiales, sed est pars quidditatis, et esse suum est in concretione ad materiam." (St. Thomas, de Potentia, q. 3, a. 2 ad 2).

natural forms (I do not say the diverse ones) cannot be absolutely opposed as if they were forms of pure spirits, because their definition embraces the notion of matter, that is to say, the possibility of an infinity of other forms which can be drawn out of this matter. Consequently the existing varieties of forms or " natural kinds " are analogues of the segments of a continuum determined a-posteriori. In this sense they are contingent and always quidditatively new. Between any two given forms in nature, there is an indefinite possibility of other forms. These forms are in the matter in a purely potential manner; and consequently the determination which any material form is, is something to be constituted as determination. It is necessary to speak in this way if one wishes to avoid the latitatio formarum (the actual latency of forms) .¹⁹²

Therefore, at the level of the concrete real, of first intention, the actuality which is " esse " cannot reflect a univocal kind or type of being.¹⁹³ The most radical and accordingly primary meaning which attaches to essentia is not " this kind" but " this existent"--that is, the fundamental notion in the term essence is one of proportion: essentia dicitur primo et per se ' proportio ad esse' (" essence bespeaks primarily and of itself a proportion to existence " ¹⁹⁴). And since there can be as such no proportion at the level of being-as-possible, the question of possible being becomes a question of how an existential proportionality is effected. Thus, we speak of " possible being " rather than of " the possibility to be " precisely because things come to be only as individuals, but the phrase may still be misconstrued.

Essences are often conceived as possible beings, the reality of which coincides with their very possibility. But we should be careful to distinguish between essential possibility and existential possibility. For, indeed, they belong in two distinct metaphysical orders, so much so that there is no way for us to reach the second one

¹⁹² De Koninck, pp. 233-4.

¹⁹³ Cf. Gilson, Being and Some Philosophers, pp. 185-6. Adler, " Solution of the Problem of Species," pp. 356-7.

¹⁹⁴ Cf. Anthony Schillaci, O. P., De passibilitate entis finiti (Mimeographed: Fall, 1961), p. 3: " Possibilitas entis non limitatur nisi per intrinsecam contradictionem. . . . Possibilitas intrinseca alicujus entis identificatur cum eius essentia, cum intrinseca possibilitas nil aliud sit nisi aptitudo rei ad esse subjectum tou 'esse', quae est ratio constitutiva alicujus rei in ratione essentiae."

through the first one. An essence is possible, qua essence, when all its determining predicates are compossible. If they are, the existence of the corresponding being is possible; if they are not, it is not. And this is true, but it is true only in the order of essential possibility, not at all in the order of existential possibility. Many metaphysicians seem to imagine that an essence cannot exist, so long as it has not received all its determinations, that, as soon as it has received them, it is bound either to burst into existence or, at least, to receive it. Now a twofold error is responsible for such an illusion. The first one is not to see that to be fully completed in the order of essentiality does not bring an essence one inch nearer actual existence. A completely perfected possibility still remains a pure possibility. The second error is to forget that the essence of a possible being necessarily includes the possible existence through which alone it can achieve its essential determination. To repeat, essential possibility is no sufficient reason for existential possibility, and since its essence is what a being is going to become, if it exists, existence itself necessarily enters the calculation of its essential possibility.¹⁹⁵

It follows ineluctably that only on the basis of causality--a basis very different from that provided by any phenomenological eidetics--can essentia be understood in the most fundamental manner, i. e., as a proportio ad esse.¹⁹⁶ The question of the actuability of essence, of the reality-status of being-as-possible, cannot be dealt with except in terms of the pre-existence of effects in their causes:¹⁹⁷ an answer framed with

¹⁹⁵ Gilson, Being and Some Philosophers, pp. 182-3, my emphasis.

¹⁹⁶ Maritain contends that " the very distinction between existence as received and existence as exercised, is understandable only in the light of the axiom causae ad invicem sunt causae." " This involution of causes is at the core of the problem." (" On the Notion of Subsistence," p. 439). Gilson is in agreement that the involution of the causes is at the core of the problem, but he seems to conceive their play somewhat differently than does Maritain. (See Being and Some Philosophers, p. 172, in contrast with The Degrees of Knowledge, p. 437). William Carlo in a recent book seems to be of the opinion that the reciprocity of the causes is outside the central issue (The Ultimate Reducibility of Essence to Existence in Existential Metaphysics, esp. pp. 20-22). In this last perspective, I, for one, lose sight entirely of the traditional species problematic.

¹⁹⁷ Gilson, Being and Some Philosophers, pp. 210-11, makes some striking observations in this connection (observations, moreover, which sound quite like Bergson: cf. " The Possible and the Real," in Bergson's The Creative Mind, New York: Philosophical Library, 1946, pp. 91-106): " Having overlooked the transcendence of existence, essentialism has entertained the curious illusion that, since, in order to be, a being must at least be possible, the root of being lies in its possibility. But possibility is a word of several meanings. It may mean the simple absence of inner contradiction in an essence, and, in such cases, all non-contradictory combinations of essences are equally possible, but none of them is one step nearer its actualization than another one. It may also mean that an essence is fully determined, so that it is actually capable of existing. Such possibles are in the condition which Scholastics would have called that of proximate potency to existence. But such a possibility still remains pure abstract possibility. Is it true to say, with so many philosophers, that, when all the conditions required for the possibility of a thing are fulfilled, the thing itself is bound to exist? Scarcely. When all those conditions are fulfilled, what is thereby fulfilled is the possibility of the thing. If any one of them were lacking, the thing would be impossible, but, from the fact that all those conditions are given, it does not follow that the thing is required to exist. The possibility of its essence does not include that of its existence, unless, of course, we count among its required conditions the very existence of its cause. But, if we do, the being of the cause is the reason why the possible is a possible being. Omne ens ex ente: all being comes from another being, that is, not from a possible, but from an existent.

" To overlook this fact is completely to reverse the actual relation of essences to existences. In human experience, at least, there are no such things as fully determined essences prior to their existential actualization. Their esse is a necessary prerequisite to the fullness of their determination."

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any other reference and put forward as fundamental posits implicitly the equivalent of a Platonic Idea. Indeed, it was the consideration of essence primarily as the focus of formal perfections, to the neglect of interrogating it (except in a secondary fashion) as the existentially established possibility for concrete presence in the world, that led thinkers into paradox and contradiction before the evolutionary species problematic.

But the irrepressible essentialism of the human mind blinds us to that evidence. Instead of accounting for potency by act, we account for act by potency. We rather forget that what is at stake is neither existence nor essence, but being, which is both. We fancy that essences, which owe their complete determination to existence, are eternally independent of existence. Everything then proceeds as though the essences of possible beings had been eternally conceived, by a divine mind, apart from the very act through which they would some day become actual beings. Thus conceived, existence does not enter the concrete determination of essences; it fills them up.¹⁹⁸

¹⁹⁸ lbid., p. 211. Cf. Joseph Owens, " The Intelligibility of Being," Gregorianum, XXXVI (1955), pp. 169-193.

In this regard we may appropriate (I do not say " concur with ") some critical reflections put forward by Heidegger.¹⁹⁹ " In connection with all the determinations of being and the distinctions we have mentioned, we must bear one thing in mind: because being is initially physis, the power that emerges and discloses, it discloses itself as eidos and idea. This interpretation never rests exclusively or even primarily on philosophical exegesis." [" The existence of nature is known directly (per se) insofar as natural things are manifest to the senses. But what the nature of each particular thing is, or what the principle of motion is, is not manifest." ²⁰⁰] " Appearance, doxa, is not something besides being and unconcealment; it belongs to unconcealment." Thus " it cannot be denied that the interpretation of being as idea [Lat., species vel forma] results from the basic experience of being as physis. It is, as we say, a necessary consequence of the essence of being as emerging Scheinen (seeming, appearing, radiance)....[" Esse objective enim consistit in ipsa orientatione per modum transcendentalem ad esse subjective."] But if the essential consequence is raised to the level of the essence itself and takes the place of the essence, what then?. . . . The crux of the matter is not that physis should have been characterized as idea but that idea should have become the sole and decisive interpretation of being." " Physis is the emerging power, the standing-there-in-itself, stability." [" Because everything acts insofar as it is an

¹⁹⁹ From M. Heidegger, An Introduction To Metaphysics, trans, by Ralph Manheim (New York: Anchor, 1961), pp. 165, 160, 152, 153, 165, 154-5, and 153-4, respectively: Heidegger's own emphases. However, let there be no misunderstanding here. Anyone who has genuinely grasped the implications of the phenomenological " Sachen selbst" and the research they in principle ground will realize how radical our appropriation shall have to be in order to place any formally philosophical reflections of Heidegger in an other than phenomenological context. Lest the reader suspect we are passing over with inadequate assessment the immense difficulties such an appropriation claims to have overcome, we refer him to our study which takes up the issue with attention to detail: " The Situation of Heidegger in the Tradition of Christian Philosophy," The Thomist, XXXI (April, 1967), pp. 159-244, esp. sec. VII, "Phenomenology: The Medium of the Being-question," pp. 222-236. A full length book on this question is in preparation.

²⁰⁰ St. Thomas Aquinas, In II Phys., lect. 1, n. 8.

actual being, the consequence is that everything stands in the same relation to action as it does to being." Thus " the measure and quality of a thing's power is judged from the manner and type of its operation, and its power, in turn, manifests its nature; for a thing's natural aptitude for operation follows upon its actual possession of a certain kind of nature." ²⁰¹] " Idea, appearance as what is seen, is a determination of the stable insofar and only insofar as it encounters vision." [Thus, not only is it true that " of no thing whatever can a perfect knowledge be obtained unless its operation is known," but we must also take account of the critical factor that " we do not know a great many of the properties of sensible things, and in most cases we are not able to discover fully the natures of those properties that we apprehend by sense." ²⁰²] Hence " being itself, interpreted as idea, brings with a relation to the prototypical, the exemplary, the ought." " From the standpoint of the idea, appearing now takes on a new meaning. What appears--the phenomenon--is no longer physis, the emerging power, nor is it the self-manifestation of the appearance; no, appearing is now the emergence of the copy. Since the copy never equals its prototype, what appears is mere appearance, actually an illusion, a deficiency. Now the on becomes distinct from the phainomenon. And this development brings with it still another vital consequence. Because the actual repository of being is the idea and this is the prototype, all disclosure of being must aim at assimilation to the model, accommodation to the idea. The truth of physis, aletheia as the unconcealment that is the essence of the emerging power, now becomes homoiosis and mimesis, assimilation and accommodation, orientation by . . ., it becomes a correctness of vision, of apprehension as representation." " The idea, as the

²⁰¹ St. Thomas Aquinas, Summa Theologiae, III, q. 77, a. 3; and Summa contra gentiles, II, c. 1, n. 1: respectively.

²⁰² Summa contra gentiles, II, c. 1, n. 1; and I, c. 3, n. 5: respectively. In the Collationes de Credo in Deum, a. 1, is the interesting remark that " our knowledge is so imperfect that no philosopher has ever been able to discover perfectly the nature of a single fly."

appearance of the essent, came to constitute its what. Thereby the whatness, the ' essence,' i. e., the concept of essence, also became ambiguous." [Thus, in many traditional writings, " In its proper intelligibility, form bespeaks a capacity for realization (dicit realizabilitatem) in any time, place, or subject whatever; and consequently, prior to existence, the essence itself of a thing is a possibility indifferent to existing in any particular time, place, or set of external circumstances (in quavis contingentia extrinseca)."] Such has been the historical interpretive consequence of according primary import to that which is secondary in the notion of finite being.

In terms of the actually existing things in the world, this is not to say that classification into kinds is fictitious, altogether false, but that such classification is shot through with analogy --and this is exactly what genetics has disclosed in a researchable manner. There are natural units, concrete universals, as it were, corresponding to the term " species." There are, that is to say, groups of individuals structured basically through sexual behavior so that the absolute range of adaptive tolerance of the members of any given group is closely coincident, yet divergent relative to the adaptive area of other groups; but within these interaction-structured groupings, within any given species, individuality is not a reducible phenomenon, neither genetically nor metaphysically, so that typological thinking (however useful it may be for certain purposes) remains of itself at the level of second intention, one step removed from the concrete real. In terms of the proportion to " esse," there can be no incidental (" per accidens") differences, " for even though a thing's existence is other than its essence, existence is not to be understood as something added over and above the essence after the manner of an accident but as if established as the result of the principles of the essence. And for that reason the term being, which is applied to a thing by reason of its very existence, signifies the same total reality as the term which is applied to a thing by reason of its essence." ²⁰³

²⁰³ St. Thomas Aquinas, In IV Met., lect. 2, n. 558.

In its complete explication the analysis of essence at the level of possible being (to which the evolutionary problematic forces philosophy) gives full metaphysical consistency to the notion of " being in and through a world." Space-time modifies and enters into the reality termed essence precisely in that there is no parent engendering progeny in a one-to-one relationship (there is no causal process in nature reducible to the transmission of an identical form); rather, there is only and always parent plus this proximally circumscribing environment, together establishing the extrinsic though immediate proportion constituting this individual existingly.

A " possible being " thus understood is in no degree virtual, something ideally pre-existent. A simple absence of external hindrance and non-contradictoriness of intrinsically constitutive notes is alone signified, together with an actual convergence of causes adequate--be it by reason of nature and chance or nature and art--to the production of a corruption (which is to say a generation: corruptio unius est generatio alterius inquantum materia prima numquam existit per se) in the world of nature. (To borrow an illustration from William Howells: " Man himself could only appear when a very high organization had been attained [absence of external hindrance]. For hands and a big brain would not have made a fish human; they would only have made a fish impossible [contradictoriness of intrinsically constitutive notes.] [While from the standpoint of an actual convergence of causes in the history of life,] man's own trail, among the many trails in evolution, was well defined: he had to be a mammal and he had to be a primate." ²⁰⁴) In a crude though preliminary way--" there is at least a poetic anticipation here," Adler contends, " of recent scientific discoveries concerning the causal efficiency of various types of radiation to produce mutations in the germ plasm " ²⁰⁵--this was hinted at by Aristotle: " Man is begotten by man and by the sun as well." ²⁰⁶ What Heidegger remarks concerning

²⁰⁴ Mankind in the Making (Garden City, New York: Doubleday & Co., 1959), p. 341.

²⁰⁵ Adler, The Problem of Species, p. 229.

²⁰⁶ Physics, II, c. 2, 194b13f. Cf. St. Thomas, In IV Met., lect. 3, n. 785.

our awareness of beings holds equally as regards their proper existence: " It is through world that the essent first becomes essent." ²⁰⁷

Thus, " to be " means " to stand within limits "; while to stand within limits means to exist as a dialectically conditioned possibility or aspect of a world: essence is only the potential dimension of contingent substance which defines it and fits it into a given population and environment according to certain active and passive capacities, while correlatively existence is essence simultaneously determined as identity with itself and reference to another, scil., the environmental world.

One would have a perfect necessity in the works of nature therefore only if one would make abstraction from the matter---principle at once of individuation and contingency--which enters into every work of nature and without which nature would not be nature. And when we speak of the " hypothetical necessity " of natural laws we mean to say that an effect is certain to the extent that form prevails over matter [actual determination over possible determination otherwise]. In other words, the laws of nature would be necessary if matter were neither nature nor principle of contingency, if in the work of nature, nature were form alone. The expression " hypothetically necessary " is therefore subject to ready misunderstanding. It does not at all apply to future contingents, except in their relation to a divine intelligence and will.²⁰⁸

" The organism and the environment," Dobzhansky notes simply, " are really parts of an interacting system." ²⁰⁹

²⁰⁷ An Introduction to Metaphysics, p. 51.

²⁰⁸ De Koninck, p. 240.

²⁰⁹ Mankind Evolving, p. 89. Gardner Murphy, Director of Research at the Menninger Foundation, applies this view directly to the understanding of the human phenomenon as such: " we often look for human nature in the wrong place; we merely look inside the living system. [Yet] any products whatever which life yields, are in a sense the products of a system of events deployed through a vast system of forces. Indeed, life can be destroyed and any given avenue can be blocked, but to find the wellsprings of human nature by looking inside the capsule is to miss the field character of the event." " A Platonic idea of intrinsic human nature as something guiding human destiny . . . needs the benefit of field theory to achieve coherence and credibility in an era in which both man and his environment need to be seen not as two realities but as two phases of one reality "-- human nature. " From such a point of view, part of the essential nature of humanness lies in the specific evolutionary trends that underlie the many demands of mankind upon life. . . ." (Human Potentialities, pp. 325, 307, and 37, respectively. See also pp. 23-4, 109-10, 177, 251-2, 270, 283, 287, 298-301). Johannes Messner, on a solidly and explicitly Thomistic basis, arrives at a similar formulation: " In the first edition of this work the matter was dealt with in the following way: Society is an accident, requiring a substance, namely, man, to support it, but an ontological accident, since man is by his nature a social being. . . . Today we would say that ontologically and metaphysically, if the expressions substance and accident are given the meaning just set down, society can only be described as an accident. It seems, however, to be another question whether the special supra-individual reality of society can be fully explained in terms of these disjunctive concepts of substance and of accident, so conceived. Certainly society is not a substance in the sense of subsisting in and for itself, independently of individuals. Yet, although society is not a substance in this sense, we cannot conclude that its being in the ontological and metaphysical sense is merely secondary in relation to the individual as such." On the contrary, " since the idea of evolution is inseparable from the nature and the natural law of man," Messner is driven to conclude that " society and the individual possess, ontologically and metaphysically, equally original being. Neither can be derived from the other or reduced to the other as the primary being. . . . The association of individuals in society indeed consists in interrelations, but not in interrelations of integrated individuals . . .; rather, it consists in interrelations through which the individuals achieve full humanity and through which, therefore, a new reality is established." (Social Ethics: Natural Law in the Western World, J. J. Doherty, trans. St. Louis: B. Herder Book Co., 1965, pp. 106 f., 76, and 108, respectively, emphasis supplied. See also pp. 36, 55, 63, 76, 84, 97, 117-121, 124, 127, 132, 139, 142. See also Erik H. Erikson, " Evolution and Ego," Insight and Responsibility (New York: W. W. Norton & Co., 1964), pp. 134-157, esp. 152 f. Indeed, mused Alexis Carrel, " it would be absurd if external reality were incapable of encompassing man in his totality. It would also be absurd if its structure did not correspond in some measure to our own. It is thus reasonable to attribute the same objectivity to the world of spirit as to the world of matter." (Reflections on Life [New York: Hawthorn Books, Inc, 1965], p. 165). In these terms, it becomes impossible to define the end for man as man without ipso facto defining the end (and thereby the direction) of the evolutionary process which man extends.

In summary: possible being does not differ from actual being simply by the difference of an efficient cause, by a merely extrinsic principle. Rather, the root meaning of essence must be derived in terms of possible being as the causal establishment of a proportion to existence, so that at the level of the concrete real, of actually existing things, essence always involves the concretion of all space-time factors (among which the generator is primary but never exclusive) entering into the initial establishment of individuality; " there could be nothing

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outside the essence of being which could constitute a particular species of being by adding to being; for what is outside of being is nothing, and this cannot be a differentiating factor." ²¹⁰ Thus, at the level of first intention, all specific kind-concepts of universal predication--essentiae specificae--are and can only be media of analogous intelligibility.²¹¹ To make more of them than this is to confuse linguistic or logical and ontological classifications. Indeed, even in the traditional species problematic where it is irreducible grades of being which are at issue more than the existential diversity of kinds:

The unity of a nature as existing in many individuals is an analogical, not a univocal, unity of being, even though the concept whereby that nature is apprehended is primarily a univocal and not an analogical concept. This must be so, for there is no way in which the one can exist in the many except analogically.²¹²

" No middle can be found," stressed St. Thomas, " between singulars and their species," for the very good reason that " actions have to do with singular things and all processes of generation belong to singular things ": " Universals are generated only accidentally when singular things are generated," i. e., they are consequent only on the consideration of reason, so that, although derived from the things, they are as qualitative universals extraneous to the individual natures which transobjectively ground them in the natural articulations and interaction-structured groupings of the environmental world.²¹³

²¹⁰ St. Thomas, In V Met., lect. 9, n. 889.

²¹¹ Cf. Adler, " Solution of the Problem of Species," pp. 356-7.

²¹² Ibid., p. 306, fn. 44 ad finem.

²¹³ St. Thomas, In I Post. Anal., lect. 2, n. 21; In Met., I, lect. 1, n. 21; VII, lect. 7, n. 1422; and esp. IV, lect. 4, n. 574, respectively. Also Summa, I, q. 13, a. 12 ad 3; and q. 85, a. 2 ad 2. Thus the conception of the " concrete universal " (as we have used the phrase in this analytic) differs from the qualitative universal familiar to the logician not by way of negation or rejection but by going beyond the static conceptions of, e. g., " horseness," " whiteness," etc., to include explicit reference to the immediate phantasmal ground of conceptualization so as to sustain analogical eidetic visualizations in which singulars are seen as structured by and holding together through interaction, as well as in their formal and qualitative isolation: the idea constantly remains within its totality. Unlike the abstract universal which prescinds from existence in order to unite its subordinates in the perfect unity of an identical " quiddity," the " concrete " universal takes existence as the basis for an analogous predication concerning individuals of a specific interaction grouping. In brief, the concrete universal is a general notion, identical with the whole of the individuals from which we obtain it. Such a conception seems to derive its fundamental possibility from the type of analogical predication referred to traditionally as " analogy of inequality " or (more precisely) " analogy on the part of the things judged, but not on the part of the concept predicated." Cf. Adler, " Solution of the Problem of Species," pp. 356 ff. St. Thomas, In I Sent., d. 19, q. 5, a. 2 ad 1. Cajetan, De nominum analogia, cap. 1; Summa, I-II, q. 66, a. 1 ad 1.

In a similar view, Charles De Koninck comments: " C'est que tout concept formellement scientifique est fondé sur une induction incomplète indéfiniment perfectible--I'inductio per descensum ne peut jamais rejoindre l'expérience au point de fermer le concept et d'en faire un universel proprement dit: sa genèse même n'est jamais terminée." (Art. cit., p. 397). Cf. further R. G. Collingwood, Speculum Mentis (London: Oxford, 1924), pp. 220-221.

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That which makes this thing to be what it is, is not an instanced universal or essential form but a unique, incommunicable, unrepeatable (i.e., historical] proportion to being-in-the-universe --which is something much finer!

That the appearance of a vegetable or animal species is due to specific causes, nobody will gainsay. But this can only mean that if, after the fact, we could know these causes in detail, we could explain by them the form that has been produced; foreseeing the form is out of the question. It may perhaps be said that the form could be foreseen if we could know, in all their details, the conditions under which it will be produced. But these conditions are built into it and are part and parcel of its being; they are peculiar to that phase of its history in which life finds itself at the moment of producing the form: how could we know beforehand a situation that is unique of its kind, that has never yet occurred and will never occur again? Of the future, only that is foreseen which is like the past or can be made up again with elements like those of the past. . . . But an original situation, which imparts something of its own originality to its elements, that is to say, to the partial views that are taken of it, how can such a situation be pictured as given before it is actually produced? All that can be said is that, once produced, it will be explained by the elements that analysis will then carve out of it. Now, what is true of the production of a new species is also true of the production of a new individual and, more generally, of any moment of any living form.²¹⁴

²¹⁴ Bergson, Creative Evolution, pp. 32 f., emphasis supplied. Cf. Bergson, " The Possible and the Real," The Creative Mind, M. L. Andison, trans. (New York: Wisdom Library, 1946), pp. 91 ff., esp. 99-104.

Within this strictly delimited context, then, we may appropriate this striking formulation of Bergson; Evolution " creates, as it goes on, not only the forms of life, but the ideas that will enable the intellect to understand it, the terms which will serve to express it. That is to say that its future overflows its present, and cannot be sketched out therein in an idea." ²¹⁵ It does but express the necessary consequence of the realization that the natural kinds, such as " the class of Birds and the class of Fishes," can be distinguished only by means of characters rooted in certain dispositions of matter, of " properties " which are of the composite and never (even as signs) of the form alone; and cannot be the subject of a notion strictly speaking abstract, or of a definition in the logico-metaphysical sense-- the necessary consequence, as De Koninck says, of the distinctively modem and even Darwinian discovery that, so far as the structures of existence in time go, " the problem of contingency in nature is not limited to questions of chance and fortune, even if these two forms of contingency are the most evident"; for the very forms themselves which articulate nature have a fixity which is only feigned.²¹⁶

It is the insufficient determination within the various grades of nature which makes possible events which go beyond even the limits of a specific natural grade, so that the contingency proper to chance presupposes a contingency, a mutabilitas in the natural cause. Whatever might be the perfection of its form, there ever remains in the composite a margin of indetermination which exceeds the formal determinations, and which constitutes the possibility of that form either falling short of its full realization, or producing an effect in nowise predetermined in either universal or particular nature (since this margin exists for the whole of nature as well).²¹⁷

One sees thus in what sense we can speak of the creation of possibles. (Obviously, creation is taken in a very broad sense.) And this idea applies not only to chance and fortune, but to the nature itself. We have already explained that the infrahuman cosmic species are not absolutely determined as regards their structure,

²¹⁵ Creative Evolution, p. 114.

²¹⁶ De Koninck, art. cit., p. 235.

²¹⁷  Ibid., pp. 241-2.

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nor consequently true a-priori. Each natural kind is new in its structure. Once established, it constitutes a determined point of departure for other species in which the determination of their source and stem will in a certain fashion be prolonged: this determination has opened the world to essential structurations which would not have been determinately possible without it.²¹⁸

Hence the need for never ending research, the danger of deductive postulations concerning the fulfillments of nature: " As a thing stands with regard to being, so does it stand with regard to truth. For the truth of those things which do not always stand in the same relation to being is not unaffected by change," since indeed " reality is not referred to knowledge but the reverse." ²¹⁹

These considerations make it possible, I think, to see that the morass of philosophical perplexities in post-Darwinian thought are due to a certain ambivalence and equivocation in the species problematic of traditional philosophy, which ambiguity the rise of evolutionary science served to underscore and make unmistakable. At the same time, by disengaging the philosophical concepts underlying the species problematic of modern biology, these considerations also make it clear that evolutionary science has not altered the structure of the question of essential natures or kinds as the metaphysician poses it, although evolutionary science has made it clear that none of the natural kinds --oysters, butterflies, elephants, eels--are so constituted causally as to correspond to the infima seu atoma species, the " indivisible kinds," of which traditional philosophy so long spoke. Since there is no evidence that any ecological population as such is differentiated by a single formal property, and vast evidence that none is so constituted, it is a violation of the principle of parsimony to insist that any of the typical populations

²¹⁸ Ibid., pp. 251-2.

²¹⁹ St. Thomas, In Met., II, lect. 2, n. 298; and V, lect. 9, n. 896, respectively. (See also n. 895). Cf. Alexis Carrel, Reflections on Life, p. 60; Man the Unknown (Harper & Bros., 1939), p. 321; Pierre Teilhard de Chardin, The Phenomenon of Man, pp. 273 ff.; Gardner Murphy, " Man-World Relations," Human Potentialities, pp. 21 ft.; G. H. Mead, Mind, Self, and Society (Chicago: University of Chicago Press, 1934), pp. 203 ff.

we readily distinguish differ as populations according to the mode termed " radical " or (traditionally) " specific." If we choose to use as our primary reference for the term species " the natural groups afforded by the instincts of mankind," as Aristotle put it, or " the categories of science illumined by philosophic knowledge" of which Maritain and Maquart speak,²²⁰ then it is impossible to retain the notion of specific natures as being convertible with metaphysical essences without disastrous confusion and an adventure in myth-making. We must rather acknowledge forthrightly that the hierarchy of essences does not correspond to nor reveal the disposition of species.

Whether the disposition of species reveals anything about the hierarchy of essences--perhaps that it does not, after all, exist --even though the former cannot correspond to the latter, is our final question. In other words, the relation of evolutionary species to the philosophical doctrine of the immutability of essence, the question of " the influence of Darwinism on philosophy," of the mutual interimplications of the respective primary concerns of the traditional and the modern species problematics, can now be seen to come down to this: once the notion of species as genetic populations has been laid bare in its ontological ground, does the notion of species as essential kinds (i. e., kinds related in such a way that each substance of a given specific nature has an essential or radically constitutive perfection lacked by its proximate inferior in specific nature, and lacks an essential perfection possessed by its proximate superior in specific nature; so that, since the whole essential difference between essentially distinct kinds lies in the diversity of their substantial forms as rendered diverse by virtue of a positive and negative difference rooted in a common perfection, essentially distinct kinds as essentially distinct must be ordered in a perfectly ordered series or unilinear hierarchy in which: a] each member has a unique position, b] there is no coordination or equality of rank, and c] each member comes

²²⁰ See F.-X. Maquart, Elementa Philosophiae, Tomus II, Philosophia naturalis (Paris: Blot, 1937), esp. pp. 12-16.

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before or after another in the ascending or descending scale of being) --does this notion retain any explanatory power at all? Or does it, like the notion of the infima species, belong to the historian of ideas and the category of philosophical myth?

Granted that the traditional and modern species problematics are and have been shown to be diverse in orientation, do their secondary implications illumine or contravene one another?

Since the traditional species problematic is inextricably bound up with the question of a natural hierarchy, it will be easy to engage it in the implications of the modern species problematic if we can show that the modern problematic as well implies inescapably a natural hierarchy. Once this has been shown, we will be in a position to judge whether the implications of the two problematics are contrary or mutually illuminating. The question of the influence of Darwinism on philosophy thus turns out to be simultaneously the question of the influence of philosophy--traditional philosophy at that--on Darwinism. It is the problem of the two hierarchies.

Let us move to a position where it comes into view.

VII. The Operational Displacement of Typological Thought in its Implications for Hierarchy.

Against the immediate background provided by this preliminary philosophical analytic and before attempting a concluding summarization of the eidetic character of organic evolution in terms of hierarchy, we must mention one other significant component of the development in this century of the science of genetics (not paleontology, as philosophers often assert) as the foundation of evolutionary explanations.

We have already seen how all explanation which accounts for reasons of being must pattern itself on a factorial conception of causality. To the extent that one or more of the four factors is unaccounted for, the explanation remains incomplete. It is possible, however, to attempt an explanation in terms of a reductive rather than factorial conception of causality, and such reductive explanations may take either of two forms. The

more important mode of reductive analysis is that which was first given expression by the Pythagoreans and the astronomers of the Academy, later taken up again by Galileo, Descartes, and Newton and subsequently extended in our own time into a universal science of nature. This is the " explanatory" method of mathematical-physics, a science which knows the real only by transposing it and not as the physical real, since it captures in things only that kind of formal cause which is the conformity of phenomena to mathematical law, and which is the basis of prediction and control inasmuch as the intelligible necessities susceptible to mathematical formulation are transcendent to the sensible object as such and insofar indifferent to its existential status. In itself, this method of converting a physical into a mathematical description constitutes a marvelous and exceptional instrument of natural science in its efforts to assign reasons for being; and so employed, it need not be a reductive explanation.

Since, however, knowledge formulated in the physico-mathematical pattern is formally and specifically distinct in its mode of definition from knowledge formulated in the philosophical pattern of " causes," there is always the danger that the instrument will be taken for an explanatory scheme in the full sense, and at once we are in the line of a reductive conception of causality.^220a

^220a J. Schwartz observes that " in its relations with science mathematics depends on an intellectual effort outside of mathematics for the crucial specification of the approximation which mathematics is to take literally." " The literal-mindedness of mathematics thus makes it essential, if mathematics is to be used correctly in science, that the assumptions upon which mathematics is to elaborate be correctly chosen from a larger point of view, invisible to mathematics itself. The single-mindedness of mathematics reinforces this conclusion. Mathematics is able to deal successfully only with the simplest situations, more precisely, with a complex situation only to the extent that rare good fortune makes this complex situation hinge upon a few dominant simple factors. Beyond the well-traversed path, mathematics loses its bearings in a jungle of unnamed special functions and impenetrable combinatorial particularities. Thus, the mathematical technique can only reach far if it starts from a point close to the simple essentials of a problem which has simple essentials. That form of wisdom which is the opposite of single-mindedness, the ability to keep many threads in hand, to draw for an argument from many disparate sources, is quite foreign to mathematics." " Related to this

deficiency of mathematics, and perhaps more productive of rueful consequence, is the simple-mindedness of mathematics--its willingness, like that of a computing machine, to elaborate upon any idea, however absurd; to dress scientific brilliancies and scientific absurdities alike in the impressive uniform of formulae and theorems. Unfortunately, however, an absurdity in uniform is far more persuasive than an absurdity unclad. The very fact that a theory appears in mathematical form . . . somehow makes us more ready to take it seriously. And the mathematical-intellectual effort of applying the theorem fixes in us the particular point of view of the theory with which we deal, making us blind to whatever appears neither as a dependent nor as an independent parameter in its mathematical formulation." (" The Pernicious Influence of Mathematics on Science," in Logic, Methodology and Philosophy of Science, ed. by Ernest Nagel, Patrick Suppes, and Alfred Tarski, Stanford: The University Press, 1962, pp. 356-8, passim. See Thomas Aquinas, In libros Aristotelis de caelo et mundo expositio, Bk. I, lect. 3, n. 24; and Bk. Ill,  lect. 3, n. 560. Also fn. 70 in Part I of Nogar and Deely, The Problem of Evolution).

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The only other way to fall into reductive explanations is to simply fail to see that the analysis of structure and function in nature always involves four correlated aspects, composition and organization as correlates of structure, agencies and products as correlates of function