NATURE AS ANIMATING: THE SOUL IN THE HUMAN SCIENCES

THIS ESSAY ADDRESSES the problem of the fragmentation of knowledge on the contemporary scene, and proposes that the rediscovery of the Aristotelian concept of nature can go far toward providing a solution.¹ Well known is the situation in academe, where specialization is the price of advancement and tenure, and where few professors are capable of ranging outside their fields to assess truth claims or attain a comprehensive overview. No less serious is the compartmentalization of knowledge at research institutes and " think-tanks," where competent scholars are engaged in detailed analyses of problems in economics, political science, and international security, but where it has proven difficult to generate studies that direct prudent action by government leaders. Here the basic problem is the perennial gap that intrudes itself between knowledge and action, between what Aristotle identified centuries ago as theoria and praxis, which we may label, following him, as that between the theoretical and practical disciplines. The direction of sensible action in the sphere of human affairs, in Aristotle's view, pertained to ethics and politics, which he regarded as practical sciences--concerned not merely with knowing but with knowing as ordered to doing. The practical orientation of scholarship

¹ The article is an expanded version of a colloquium paper read at the Woodrow Wilson International Center for Scholars, Washington, D.C., on November 8, 1984, with the title "The Idea of Nature: Its Contemporary Relevance for Ethics and Politics." An earlier draft was read in the Seminar on Problems of Authority and Participation at the same Center on August 13, 1984, with the title "The Modeling of Nature: Can the Soul Be Put Back Into the Human Sciences ? " The author wishes to thank Edmund Pellegrino and Otto Bird for their helpful commentaries on the colloquium paper, and James Billington, Prosser Gifford, and Ann Sheffield for providing the stimulating ambience in which it could be written and presented.

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--the ideal embodied in " knowing as ordered to doing "-- is a concern that goes far beyond the needs of academe and research institutes. Its neglect on the contemporary scene is but an instance of the more pervasive fragmentation of knowledge that characterizes our culture.

The theme of this essay is that the concept of nature, particularly as animating and instantiated in the human soul, can be fruitful in overcoming such fragmentation in a basic way: by reuniting the physical and the human sciences and showing how action or doing can be related to both.² By the physical sciences we mean the speculative or theoretical sciences concerned with nature, the phusis of the Greeks, whence the term " nature " in our title. Among such sciences one might include physics, astronomy, chemistry, biology, psychology in its more theoretical aspects, and so on. The human sciences we take to embrace those concerned with man's affairs: the social and political sciences, ethics and politics, economics, the behavioral sciences in their more clinical aspects, etc. They less obviously are concerned with nature, and yet they are but manifestations of human nature in action, as will be shown in the sequel. Thus nature as seen in the world of nature and as embodied in human nature as part of that world is the concept around which we propose our integration.

The regulative idea is simple: nature is an intrinsic principle of perfective activity, and the better we understand a nature or a natural kind the more we can appreciate how it should act. Thus we would bridge the " is " and the " ought " by rooting the norm for action in an objective standard: a nature that is not completely refractory to understanding. Here it is important to observe that there is a vast difference between knowing all there is to know about a nature and having no knowledge of it at all. By the somewhat elliptical expression, " a nature that is not completely refractory to understanding,"

² For an exposition of the concept of nature and the intellectual context in which the following development should be situated, see W. A. Wallace, "The Intelligibility of Nature: A Neo-Aristotelian View," Review of Metaphysics 38 (1984), 33-56.

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we mean one of which humans can have a progressively better and deeper comprehension with each advance of science. A method well suited to illustrating such progressive understanding is the modeling technique, and throughout this essay we will refer to models, or schematic diagrams, to bring home the point. To be able to model something implies at least a partial grasp of what it is.³ The modeling of nature is the theme that underlies the speculative part of this presentation, on which the practical part is later based.

Nature in the Natural Sciences

When we speak of nature we generally mean what we experience when we go into a primeval forest or gaze on a starry night into the depths of space. Nature for us is what is free from human intervention and artifice, what comes into being and runs its course without benefit of man's assistance, to say nothing of his contaminating influence. In this sense we differentiate the world of nature (Nature, say, with a capital " N ") from the world of art and of artifact. The latter is man's creation, whereas the former exists independently of man, although it is available for his observation and, in some cases, for his manipulation and use.

Aristotle's definition of nature is somewhat more refined than this.⁴ While differentiating the natural from the artificial, as we do, he also took pains to distinguish it from the forced or violent, from what is done by coercion instead of coming from within the thing being studied. In this way of speaking a nature (let us call this nature with a small " n ") is a source of the activities it originates and so are peculiarly its own.

3 This theme is developed in W. A. Wallace, Causality and Scientific Explanation, 2 vols., Ann Arbor: The University of Michigan Press, 1972-1974, 2:257-264, and in idem, "Causality, Analogy, and the Growth of Scientific Knowledge," Tommaso d'Aquino nel suo settimo centenario, 9 vols., Naples: Edizioni Domenicane Italiane, 1978, 9:26-40. The latter essay has been reprinted in W. A. Wallace, From a Realist Point of View: Essays on the Philosophy of Science, 2d ed., Lanham-New York-London: University Press of America, 1983, 212-227.

4 Physics, B.1, 191b21-23.

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Such natures, which go to make up the world of Nature, are found in plants and animals, in chemical elements and compounds, in stars and planets, in human beings, all of which come into being and pass away, and yet enjoy periods of relatively stable endurance during which they respond to, and interact with, things around them. Some natures obviously are animate whereas others are inanimate, yet both types are knowable through observable properties and behavioral characteristics. To say of something that it is sulphur, or a geranium, or a horse, is to specify its nature; this we learn not merely from its appearance but from the way it acts and reacts in a variety of circumstances.

To be more specific, the nature of a thing is manifested by the way it exercises its natural powers, either spontaneously or in reaction to external influences. Such powers constitute its " inner dimension," one might say, and they can be grasped by us to the extent that we are successful in modeling the ways in which they act. We may illustrate this by taking a few examples from the inorganic, plant, and animal worlds, to show how the advances of modern science have yielded progressively fuller knowledge of natures and of the powers through which they can be known in these respective domains.

Powers of the Inorganic

The inorganic or inanimate world is that of the non-living-- a terminology that differentiates it from the living and presumes that the difference is easily recognized. Admittedly in Nature there are entities whose kind is difficult to establish and so might leave one in doubt as to whether life can be predicated of them. But most of the objects we encounter in our surroundings do not present this difficulty. We classify them as some type of plant or animal if they manifest vital activities at one level or another, and if not, we regard them as inanimate. Planets and stars, on the other hand, present more of a puzzle for not being close at hand. But with a few exceptions civilized people have tended to include them among the non-living, since they give no indication of undergoing the

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changes one usually associates with life processes. Thus the inorganic world is commonly thought to be made up of chemical elements and compounds, of crystals and minerals of various types, of heavenly bodies, and then of the various particles of which all of these might be composed, such as molecules, atoms, electrons, etc.

For over two thousand years inorganic natures resisted attempts at understanding, and it was only with the Scientific Revolution that real progress was made. The first step came with the recognition that the matter of the heavens is basically no different from terrestrial matter and so does not require a special element or quintessence to supplement the four " earthly" elements: fire, air, water, and earth. The second came with the breakdown of such elements as water and air into more fundamental constituents: hydrogen, oxygen, nitrogen, carbon, and their associated compounds such as carbon dioxide. From this it was a straightforward matter to develop the Periodic Table of the elements wherein they are grouped into kinds, and then to explain their chemical properties in terms of their atomic structures. In the present day, with the rapid growth of physics and chemistry and affiliated branches such as astrophysics, geology, meteorology, and oceanography, we can boast a fairly exhaustive knowledge of inorganic natures-- possibly superior to that we have of the organic.

How do we come to know an inorganic nature such as that of a chemical element? Our thesis is that we know a nature to the extent that we can model it in terms of its components and the ways in which they function. There are many models we might use to illustrate this, but for purposes here the one developed by the Danish physicist Niels Bohr to explain the Periodic Table of the elements is most instructive.⁵ In it the atom for each element has a central nucleus in which most of its mass resides, surrounded by one or more orbital electrons

5 An elementary explanation of this model, as well as of others used in recent physics, will be found in Michael Chester, Particles: An Introduction to Particle Physics, New York: Macmillan Publishing Company, 1978, 31-36, 68-79.

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arranged in concentric circles or shells. Those acquainted with modern chemistry know how these electron configurations can serve to explain the affinities and other properties of the respective elements. The one valence electron in hydrogen, for example, lets us understand why two hydrogen atoms are necessary to complete the outer shell of oxygen and thus form the H₂O molecule; the two valence electrons in helium complete its shell and make it an inert gas; the valence electron in sodium explains the affinity of that metal for chlorine to form salt, and so on.

One can introduce further complication into the Bohr atom by introducing the Bohr-Sommerfeld model, wherein circular electron orbits are replaced by elliptical orbits that assume various orientations in space.⁶ This more complex model can be used to illustrate the Pauli exclusion principle, which states that no two electrons in any atom may occupy the same energy state; in it each electron in a given orbit must be shown with a different spin or orbital position. Usually orbits are pictured for the normal or unexcited states of the atom. If one wishes to explain the ways in which an atom absorbs and emits electromagnetic energy, still more complicated configurations are required. For example, when electrically energized the sodium atom emits a bright yellow light, familiar to many of us from the sodium vapor lamp. The emission of that light is caused by one of its electrons falling from an excited state (i.e., one of higher energy) back to its normal or ground state. Quantitative calculations aside, one can visualize such activities and reactivities of sodium in terms of this model, and so gain an understanding of its chemical and spectroscopic properties in almost unlimited detail.

Other types of models may also be mentioned as furnishing additional insight into inorganic natures. The lattice-structure model of the crystal, showing for example how sodium and chlorine atoms form the cubical crystal of salt, or how the electron transitions in an emerald bring about its characteristic

6 Ibid., 37-43.

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green color, or how semiconductors such as a silicon chip operate, is equally illuminating. Also of help are models of the atomic nucleus, such as the liquid drop model, which shows how protons and neutrons are arranged and interact in fusion and fission and in various kinds of radioactivity. Then there are models of stars in the stages of their development, of pulsars and how they emit radiation, and of quasars, black holes, and other cosmic phenomena.⁷

What is amazing about these recent developments in physics and chemistry is the extent to which they have unveiled the energies or powers latent in the inorganic world. Such powers are commonly regarded as potentials that give rise to various forces, now classified into four basic types. First is the gravitational force, which accounts for the weight or gravity we experience in heavy bodies. Then there is the electromagnetic force, which serves to explain chemical reactions as well as electrical and magnetic phenomena. Third is the weak force, believed to be associated with radioactive emissions from atomic nuclei. And finally comes the strong force, that exerted between particles within the nucleus, which provides an understanding of the nuclear reactions studied by the high-energy physicist. These four forces are the scientist's ways of speaking about natural powers in the domain of the inorganic. Much effort is now being expended to tie them together in a unified mathematical theory. The important thing to observe is that, mathematics aside, they are already unified in the nature of which they are the power manifestation.

Let us explain the last statement. It seems clear from recent science that hydrogen and helium and sodium, and silicon and salt and emerald, are natural kinds, that is, they are substances with natures, not artifacts, that have their own characteristic

7 Most physics and chemistry textbooks are replete with illustrations of such models; see, for example, Henry Semat and J. R. Albright, Introduction to Atomic and Nuclear Physics, 5th ed., New York: Holt, Rinehart, and Winston, Inc., 1972 ; also Remo Ruffini and J. A. Wheeler, " Introducing the Black Hole," Physics Today 24.1 (January 1971), 30-36, 39-41, and A. Hewish, "Pulsars," Annual Review of Astronomy and Astrophysics 8(1970), 265-296.

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activities and reactivities. The four natural powers diagrammed in the upper portion of Figure 1 indicate these activities and reactivities in a generic way. In any one element, say in sodium or radium, the Bohr-Sommerfeld atomic model and its associated nuclear model show precisely how these powers are present and balanced in the particular nature they represent. In radium, for example, all four powers find their manifestation, whereas in sodium radioactive emission is muted because of the stable structure of its nucleus. The reductivist mentality seems satisfied with cataloguing the components of such natures--electrons, protons, neutrons, mesons, neutrinos--without reference to the formal and material elements that unify them into functioning units.

It is difficult to diagram such formal and material elements precisely because they effect unities in being and in operation. An attempt to do so, however, is schematized in the lower portion of Figure 1. This is labeled simply "A Nature in the Inorganic Realm," meaning by this a particular nature understood indeterminately, and so applicable to each and every nature in the realm of the non-living. What differentiates the lower from the upper portion of Figure 1 is that the former has a point identified in its center, from which radiate a series of concentric circles that overlay the four natural powers. The point is a schematic way of representing a concept found in Aristotle's Physics that of hulē protē, materia prima, or protomatter, to use the English equivalent.⁸ Protomatter, for Aristotle, is the basic material constituent of the universe. The circular lines that radiate from it are meant to convey the impression of a field that " expands " protomatter, as it were, and forms it into a substance of a particular nature. In so doing it unifies the four powers and makes of them a functioning whole. The field itself stands for the nature or the defining form of the particular substance, say, the element sodium. At once it is a unifying form, conferring a unity on the components of that element; a specifying form, making those

8 Physics B.1, 193a29.

components be and react in a way characteristic of sodium; and a stabilizing form, preserving the identity of the element and maintaining the unity of its components under external influences to the extent that this is possible. It is called form from the Greek term Aristotle used to describe it, morphē⁹; the scholastics designated it, perhaps more accurately, as the forma substantialis, since it is the factor that determines the substance to be what it is. One can thus understand any particular substance in light of a potential principle, a basic protomatter (however one wishes to understand this--perhaps as a pure conservation principle bereft of all specific determination) , plus an energizing or actualizing principle, a unifying, specifying, stabilizing natural form that makes that substance be what it is.¹⁰

The schematic diagrams of Figure 1, it should be emphasized, are generic in character. They should be viewed only in conjunction with a model for a specific substance, say, the Bohr-Sommerfeld model of the sodium atom or the radium atom. The nature of each of these substances is manifested by the specific or distinctive way in which its powers operate. Their various components are constituted and energized, as it were, by the form that underlies such powers and causes them to be and to act in the way they do. This natural form, modeled in Figure 1 as a field, is the nature of sodium or radium, which we grasp as soon as we come to know these particular chemical elements with their distinctive powers and characteristics.

Powers of Plants and Animals

Unlike the inanimate world, the world of plants and animals offers a rich abundance of natural kinds that have been recognized as such for millennia. Students of nature have not been

9 Ibid., 193b5.

10 For an explanation of how the Aristotelian concepts of hulē and morphē have application in recent high-energy physics, see W. A. Wallace, " Elementarity and Reality in Particle Physics," Boston Studies in the Philosophy of Science 3 (1968), 236-271, reprinted in From a. Realist Point of View, 2d ed., 185-212.

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content to distinguish the living from the non-living, but have worked seriously at differentiating each kind from every other. In this project a " natural kind " designates a class of things alike in all their essential characteristics, sharing a common nature though differing in individual traits. One of the earliest recognized tests is the ability of organisms to reproduce, i.e., to produce another individual of their species. Thus specimens that can interbreed and produce normal offspring are regarded as having the same nature even though they differ widely in individual characteristics.

The unity in being and operation found in plants and animals is easily recognized: that is why we call them " organisms," for their many organs act for the good of the whole. Aristotle was aware that such organs exercise the basic powers required for life processes, which he identified as those of nutrition, growth, and reproduction.¹¹ Modern biologists, studying in detail the mechanisms whereby chemicals serve the needs of organisms, have a more nuanced understanding of the ways in which these powers function. Like physicists and chemists, they employ models to gain an insight into such processes as homeostasis, metabolism, and the control of genetic factors in development and reproduction. For purposes here it may suffice to note models for the first two, homeostasis and metabolism, as complementing the Bohr atom by furnishing an insight that is more distinctive of the life sciences.

Homeostasis is a self-regulating process whereby a living thing maintains its stability while adjusting to conditions that are optimal for its survival. It is usually modeled by some sort of device that is capable of modifying itself, through a negative feed-back mechanism, so as to maintain dynamic equilibrium with its environment.¹² As a minimum this involves a

11 Aristotle's thought was, of course, taken over and systematized by St. Thomas Aquinas in his Summa theologiae; on the vegetative powers, see Prima Pars, q. 78, a. 2. Much of the remainder of our exposition follows the development of Aquinas in qq. 75-83 of the Treatise on Man, and the use he makes of it in his Pars Prima Secundae when developing his moral doctrine.

12 The homeostatic process is well described by L. L. Langley, Homeostasis, London: Chapman and Hall, Ltd., 1965, 12-14.

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register of some type that responds to changes within the organism. Somewhat like a home thermostat the register activates a modulator that works to achieve the desired adjustment; when this is effected the result is fed back and the register deactivates the process. In plants such control is effected chemically by concentrations of various substances in different parts of the organism; in animals chemical action is supplemented by that of the autonomic nervous system. But whereas mechanical and electrical regulating devices are rigid and determined in their operation, biological regulators are flexible and adaptable. The plant hormone, auxin, for example, works homeostatically to regulate growth by controlling water intake and so stimulate or inhibit the rate at which the plant develops--variable over a range, yet optimal considering the environment in which the plant is placed.

Metabolism is the term reserved for chemical changes whereby energy is provided to maintain life functions. All organisms derive their energy from sunlight; most plants do so directly through photosynthesis, whereas animals and some plant forms use the products of photosynthesis as food and thus as their indirect energy source. Chemically the processes are extremely complex, and yet they are so finely controlled that, from the foods available, precisely the required amounts of energy are produced when and where they are needed within the organism. Elaborate models can be constructed, for example, to illustrate the metabolic process (also homeostatic, by the way) whereby the amount of sugar is controlled in the blood of an animal organism. Sugar or glucose builds up from the liver and directly from food; it is lowered by excretion, conversion to fat, and the use of energy. An effective model provides an understanding of the metabolic process by showing how these and other factors serve as controls to maintain the blood glucose at a desirable level.¹³

Homeostasis and metabolism are pervasive in the plant and animal worlds, their links, so to speak, with the physico-chemical

13 Ibid., 40, 64-65.

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realm of the inanimate. Other powers may be built upon these to take care of the complex functions found in the different kingdoms, phyla, classes, and so on. For vegetative life the basic natural powers are shown in Figure 2. Directly above the four inorganic potentials are drawn the control powers for homeostasis and metabolism, the first controlling the organism's links with the environment and the second the internal processes of food and energy conversion. The two additional powers on the top line are the developmental power, whose function throughout the organism has been likened to that of a " morphogenetic field " as it effects cell differentiation and growth, and the reproductive power, which brings about the production of new individuals within the species.¹⁴

As in the previous diagram of the powers of the inorganic, Figure 2 is a generic model applicable throughout the plant kingdom. For any one type of organism, as the botanist well knows, these powers and the natural form that underlies them develop the organ systems necessary for the life activities of the particular species. Figure 3 models that form, or the nature of a specific plant organism, as an energizing field.¹⁵ Stated otherwise, although a generic model, it is meant to represent the nature of an organism of a species or type, such as that of a live geranium or live oak. Only when the " live " is added, we should note, do we have a true geranium or a true oak. When the plant or tree dies the nature is no longer there, the powers cease to activate the organ systems, and the substance decomposes and reverts quickly to the level of the inorganic.

The animal kingdom is usually differentiated from that of plants by its possession of sentience and mobility, and for these

14 More complicated models are at hand for the various phases of cell division and the DNA molecule, showing how it functions in the transmission of genetic codes, but discussion of these need not be entered upon at this point.

15 Here the boxes representing the various natural powers are designated by the same capital letters as shown in Figures 1 and 2, but the distinctive activities that emanate from the powers are indicated to the left and right of the powers, thus emphasizing the point that the nature itself is the root source of the activities that take place within, or emanate from, the
organism.

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characteristics additional powers and organ systems are required. Although one may speak of a plant's behavior, the term "behavior" is usually reserved for distinctively animal activities. Touching an oak tree reveals little about life functions that may be going on within it, but touching a frog gives a quick indication of whether the frog is alive or dead. The well known stimulus-response model makes use of this fact to lay out the behaviorist program for animal experimentation. Early behaviorists concentrated exclusively on externally observable, and usually measurable, features which they identified as stimulus and response; the interior of the organism they regarded as a " black box " that must forever remain opaque to scientific investigation. But with the development of computers, more complicated models have been developed by researchers in cognitive science that give a deeper understanding of sensation and the ways in which it may be linked to motor activity.¹⁶

A computer-driven robot, for example, might be diagrammed schematically as composed of four interacting units, two to account for stimulus functions and two to handle response. In the case of stimuli, a sensor unit would normally be required for their reception, to which a memory unit could be added for retention and later reference; to effect appropriate response, a selector would then be desirable to activate alternate drives depending on signal reception, and finally a motor unit would be needed to carry out the elicited commands. Four capabilities or powers--sensor, memory, activator, and motor--would then suffice for the simulation of activities usually associated with the animal kingdom.¹⁷

Just as the Bohr atom and the homeostat can be used to model natures in the inorganic and vegetative realms respectively, so a robot of this kind may be used to model natures at the level of the sensitive. The natural powers that explain

16 For an elementary description of such devices, see the author's essay, " Computers and the Modeling of Man," From a Realist Point of View, 2d ed., 245-271.

17 Ibid., 259-261.

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animal life, to be sure, build on the powers already investigated for the realms of the inorganic and the vegetative. But not much ingenuity is required to generalize the four capabilities just sketched for the robot to obtain the corresponding natural powers that can complement the eight powers required for plant life. The sensor would be replaced by the external senses--sight, hearing, taste, touch, and smell; memory would be expanded to include all of the internal senses associated with the brain and central nervous system--perception, imagination, memory, and instinct; the activator would become behavioral response--various emotional reactions as sources of impulsive and aggressive behavior; and the motor would be replaced by the range of motive powers associated with the animal's organs of movement.¹⁸ Thus twelve natural powers in all should be sufficient to account for the activities that characterize the animal kingdom. These function as a type of hierarchical structure wherein the four powers of the inorganic subserve the four plant powers, and wherein all eight in turn subserve the distinctive powers required in an animal organism.¹⁹ The ensemble of these powers operating within the animal is what constitutes its nature. By analogy with the natures already diagrammed for the inorganic (Figure 1) and for the plant world (Figure 3), a nature in the animal kingdom will then be modeled by the radiating circles or field that energizes all of the powers and enables them to function as a specific unit.²⁰ This model, as heretofore, is itself generic in kind; to be appreciated it must be associated with an organism

18 Ibid., 261-263.

19 See the schematic diagram represented below in Figure 4. This shows the fourteen natural powers characteristic of the human organism. Two of these should be deleted to have the diagram applicable throughout the entire animal kingdom rather than restricting it to homo sapiens alone. These are the boxes in the top right portion of the figure--those for the powers of intellect (I) and will (W), which are found only in humans.

20 The field shown in Figure 5 below approximates that of an animal nature. To be more precise its center should lie exactly in the middle of the four boxes designating the powers of the plant kingdom, and the radiating circles should not extend so far as to overlap the powers of intellect and will, since an animal nature as such is incapable of thought and volition.

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of a particular species, say, a squirrel. A live adult squirrel is able to exercise all of these natural powers, and it does so in ways that contribute to the unity and well-being of the entire organism. Its life has an inorganic base in the sense that its bodily components obey all the laws of physics and chemistry; it assimilates its food and grows and develops, even procreates; and all of these functions undergird its sensitive and mobile capabilities. But the squirrel differs from the robot in an important respect: it is self-developing and self-activating--another way of saying that it is alive. The robot works only when energized; the squirrel is by nature energized. And yet the concept of being "energized" casts light on the function of the natural form in the realm of the living. Just as a robot is inert or dead when it lacks a source of energy, so the squirrel is dead when it no longer is animated, when it no longer has its nature, when the powers deriving from that nature become inoperative, and when its structure disintegrates and the organism itself decomposes into inert chemical substances.

Powers of Man

With this we have all the materials necessary to discuss man's nature and the powers associated with it. A human being is an animal rationale, which is to say that his rationality is what distinguishes him from brute animals. To explain this two additional powers have traditionally been invoked, namely, the intellect and the will. The first--alternately referred to as reason, understanding, insight, etc.--supplies man with a type of knowledge superior to that of the lower animals, called intellectual knowledge to differentiate it from that of the senses. The second is an affective power that can rise above the level of emotional response; it takes its intimations from the intellect and is the root source of the personal decisions a human being makes precisely as human.²¹

21 For a fuller elaboration, see From a Realist Point of View, 2d ed., 263-269, and also the material referred to there in an earlier essay in the same volume, "Basic Concepts: Natural and Scientific," 45-49.

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Figure 4 shows all of the natural powers of the human organism, basically those of the higher animals but adding to them the distinctive powers of intellect and will. The powers are arranged hierarchically in the diagram, which should be read from bottom to top to retrace the sequence followed thus far in developing our conception of nature as animating. At the lowest position are the four basic forces of the physicist from Figure 1, only now shown in interaction with, and so subserving, the natural powers of plant life. In the middle position are the properly vegetative powers of Figure 2, here shown connected with, and in symbiosis with, the physico-chemical powers beneath them and the animal powers above them. And finally, at the top position, are the natural powers required to support animal life with its distinctive properties of sentience and mobility. The topmost grids are shown as a type of stimulus-response mechanism (represented by the S and R symbols to the left of the diagram) and are labeled ES for external senses and IS for internal senses along the stimulus line, and BR for behavioral response and MP for motor powers along the response line. To accommodate the additional powers found in human beings, the diagram has then been extended to the right to include intellect (I) at the termination of the stimulus (or knowledge) line and will (W) at the beginning of the response (or action) line. Fourteen powers in all are thus required to signal the capabilities of the human organism and their various modes of support and interaction within its life processes.

Human nature itself, following the convention already explained, may now be modeled by an energizing field laid over all of these powers, as illustrated in Figure 5. As with previous models of natures, this is not a model of an individual person. Rather, it applies to the species as a whole and so should be thought of as instantiated in each and every adult human organism. Human nature, in this understanding, is a unifying and stabilizing principle to which all of man's life activities can be traced. In virtue of that principle a person thinks, wills, perceives, reacts emotionally, senses, and moves his

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limbs; it also lies behind the homeostatic equilibrium he maintains with his environment, the metabolism whereby he assimilates food, the processes through which his body grows and develops and ultimately reproduces. It even explains the ways in which ion concentrations are maintained in his body fluids, how radioactive tracers are carried to one or other of his organs, and ultimately why he floats in water and falls in accordance with the laws of gravity. In a word this natural form is what makes him one organism, with a diversity of parts, all capable of being coordinated in unified activity, which reaches its perfection in his rationality and exercise of free will.

Thus far we have been using the terminology of nature and form in analyzing the powers and activities of inorganic, plant, animal, and human substances but have made no reference to soul--a key concept in this essay, which, as intimated in its title, assumes considerable importance in the human sciences. Nature, following Aristotle, is an internal substantial principle of characteristic activity; it may refer to the basic protomatter explained above, or it may refer to the distinctive form that makes the substance be what it is.²² We have been modeling the latter referent as an energy field, and in this way have been able to account for the unity and stability of inorganic substances as well as those of the organic realm. When we move from the non-living to the living, however, we note a difference in the activities that emanate from the specifying form: these are now life activities, those, namely, that characterize living organisms. Energy serves as a useful analogue to describe all activating principles behind the operations of nature, but it is especially apt for shedding light on the animating principle that makes organisms operate the way they do. Just as a robot will function only so long as it has within it a source of electrical energy, so a plant or an animal will exercise its life functions only so long as it is energized properly. This energizing or animating principle in living things has traditionally been

22 Physics, B.1, especially 192b33, 193a29, 193b5.

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known as the anima or soul. An organism is alive and functioning only to the degree that it is animated or besouled, or, in other words, to the extent that it has a soul. Nature as animating is therefore nature in its " ensouling " function: it is this function that enables us to speak of a plant soul, an animal soul, and a human soul. Such souls are nothing more than the correlates of the forma substantialis that effects specific unity and stability at the level of the non-living. Each is successively capable of supporting the increasingly sophisticated activities to be found in the plant, animal, and human spheres. The human soul is the apex of this formal hierarchy. All the powers we associate with humans are basically its powers, for only when the body is energized by the human soul can these powers be activated to have the body function in truly human fashion.

Entitative Perfection

Before proceeding to an analysis of human nature in action, which should follow at this point, we will address briefly the problem of the entitative perfection of natures, that is, their perfection in being, for the light this may shed on their operational perfection, their perfection in operation. It seems more or less evident that there are degrees of perfection in natures according as they manifest more and better powers or capabilities. In this sense plants are superior to minerals, animals to plants, and humans to animals. Even within a kingdom or species, or within an individual over time, however, it is possible to speak of one state being better than another. This is difficult to see in the inorganic realm, though perhaps one would be prepared to admit that a diamond is better than a piece of charcoal, although the chemical nature is the same in both--pure carbon. Crystals and precious gems, in a way, manifest the perfection of an inorganic nature for they show it in its most stable and unified state, able to conserve its being against deleterious environmental influences.

In the realm of the living, some individuals are better adapted than others, stronger or more agile, for example, and

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thus, as Darwin pointed out, more fit for survival. But individuals themselves vary in their capacity for exercising life functions from time to time. At one period their organ systems might be working well, at another not. There is a general name for this well-working of an organism as a whole, and that is " health." Plants and animals are said to be healthy when their natural powers activate their organs properly and all their systems function well. Then they are said to be " well " themselves--our common way of indicating that we are healthy. There is such a thing as a healthy geranium and a healthy squirrel, and, of course, our preeminent concern is with the healthy human being. This is the sense of entitative perfection on which we would focus.

What is health, and how does it related to a nature that is said to be healthy? The traditional reply is that health is a habit or disposition that characterizes the organism as a whole, but is especially manifest in the way a natural power energizes or activates its respective organ system.²³ In this sense one can have a healthy liver, healthy circulation, and healthy limbs; the aggregate of all these healthy systems constitutes the health of the organism. With a little ingenuity a symbolism can be devised to show how a habit or disposition of this type can modify its relevant life powers, both in themselves and in their relationships to other powers, so as to render an organism " healthy " in the various ways it functions. With such a symbolism the schematic diagram of Figure 4 can be augmented to model how the natural powers of the human organism may be disposed operationally, and so register, in a general way, that organism's state of health.²⁴

23 This is the way in which the concept is generally viewed within the Aristotelian tradition; for its application to the contemporary situation in medicine, see L. R. Kass, "Regarding the End of Medicine and the Pursuit of Health," The Great Ideas Today 1978, Chicago: Encyclopaedia Britannica, Inc., 1978, 72-103.

24 In the schematic diagrams employed thus far, powers have been represented by boxes; to represent a habit or disposition that modifies these powers, small hexagons may now be added to the boxes. Such hexagons, with the small letter " h " inserted within them to designate " health " or " healthy operation," are shown in Figure 6 below. There they are appended to the sentient and behavioral powers of the animal organism; they could likewise be added to the vegetative powers on Figure 2 and 4, if one wished to indicate the state of health of such powers in relation to the organ systems they activate. They would not be added, on the other hand, to the inorganic powers or forces of Figure 1, since the qualification "healthy" is usually reserved only for powers in the realm of the living.

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The sense of entitative perfection just described may now be extended somewhat to include more than bodily health (that associated with organs and organ systems), to include the type of health that is peculiarly human, the health of the mind. The mind is healthy when it thinks properly, and this requires more than a sound body, more than a healthy brain and nervous system. It requires also that the intellect be habituated to correct ways of thinking about various subject matters. Such habits are sometimes called intellectual virtues. An alternate term is sciences, understanding science in the broad sense of systematic knowledge about any subject. In this meaning a science may be regarded as an entitative perfection of the intellect, much in the way that health may be regarded as a similar perfection of other life powers.²⁵ We shall have occasion to return to this comparison as we move now to an examination of human nature in action and the remaining ways in which it may be perfected in the order of operation.

Nature in Action

Earlier the claim was made that the better we understand a nature the more we can appreciate how it should act, that we can bridge the " is " and the " ought " by rooting the norm for action in an objective standard, a nature that is not completely refractory to our understanding. Now it is time to justify that claim in the context of the human nature we have just examined to show how it can be a norm for action and in this

25 In the schematic diagrams of Figure 6 below, one may again note the hexagons marked with the letter " s " appended to the intellect box ; the term " science " for which the " s " stands is to be understood generically, since there are many sciences with which a particular intellect may be endowed, and to possess one is not necessarily to possess them all.

way have contemporary relevance for human sciences such as ethics and politics. Recall that at the outset we characterized ethics and politics as practical sciences, sciences concerned with " knowing as ordered to doing," and thus our concern now is not with the entitative perfection just discussed but rather with an operative perfection, a perfection in praxis, that must be the goal of every practical discipline. This goal is sometimes referred to as " practical truth," which perhaps can be illustrated with simple examples drawn from engineering and the health sciences.²⁶

Perfection in Praxis

The engineer works mainly with the inorganic natures discussed in the first part of this essay. He must investigate the forces and potentials found in such natures, but not merely to understand them, rather to harness them, channel them in the right direction, so to speak, to produce artifacts that serve the needs of man and society. His knowledge is not measured by how good a theory he can formulate about electron flow in semiconductors, but by how well he can design and produce a reliable computer, to give a current example. The practical truth of the engineer is seen in his products: the skyscraper, the video recorder, the space shuttle, all of which must not only come to be but must also function properly. The engineer's knowledge consists in knowing the right thing to do, in construction and in operation or maintenance, to assure the attainment of the goal embodied in the material artifact he aims to create or produce.

What the engineer attempts to do with inorganic natures has obvious parallels with the work of the practitioner in the health disciplines. Health is a concept we normally associate only with organic natures. So as to make full use of the material

26 For an explanation of the notion of practical truth, see W. A. Wallace, The Role of Demonstration in Moral Theology, Washington, D.C.: The Thomist Press, 1962, 117-140; some of this material is summarized in the essay, " Being Scientific in a Practice Discipline," From a Realist Point of View, 2d ed., 273-293.

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developed above about plants and animals, let us include under health practitioners horticulturists and veterinarians as well as physicians and surgeons. All must possess detailed knowledge of the organ systems and powers that activate them in the organisms with which they work. No truth available to the botanist or zoologist falls outside their ken, and yet they cannot rest satisfied with such speculative knowledge alone. They must grasp the natures of the plants and animals (including human animals) in their care, and then give whatever assistance they can devise to bring such natures to proper, healthy functioning. They spend much of their time with malfunctions or dysfunctions, for these must be understood if correct functioning is to be restored. But the measure of their truth or knowledge is not what they know about functions or dysfunctions, but rather what they are able to do with them to restore an ailing organism to health and in this sense attain practical truth.

To show this concern of doctors and engineers with proper doing or acting as opposed to mere knowing, the upper portion of Figure 6 redraws the topmost section of Figure 4, only labeled slightly differently to indicate the main human powers and how these function in the " knowledge line " and the " action line " respectively. Man's knowledge line is perfected to the degree that his organs and powers of sense and perception are healthy (indicated by the small hexagons with the letter " h ") and to the degree that his intellect, at which the knowledge line terminates, is perfected in the order of science (shown by the hexagon marked with the letter " s "). In many areas, to be sure, his sensations and perceptions are inferior to those of the lower animals, but provided his sense organs and nervous system, brain, etc., function properly, his intellect is able to make up for their limitations. Yet his knowledge reaches its full perfection as human only to the degree that it is perfected along the lines of the intellectual disciplines--the pure sciences and the humanities--which enable him to grasp in a more or less systematic way all that is humanly knowable.

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The action line is more complex, if only for the fact that it is dependent on the knowledge line and is influenced by it in various ways. The first influence is shown by the path connecting perception and emotion to illustrate the case where something perceived elicits an emotional response that prompts the knower to action. This is the way in which brute animals respond to their environment; provided their instincts are good and their reactions healthy it is sufficient for the activities they require for survival. With humans the case is different, for knowledge responses can come from the intellect rather than from perception alone. If they come from the intellect they are mediated to the emotions through the will, man's power of choice and personal decision. An emotivist theory of behavior might urge, " If it feels good, do it," but experience quickly shows that such is not always the best course of action. Man is a rational animal and he can perfect his nature only to the extent that he acts reasonably, that his emotions are under the control of his reason and his will. Voluntary activity is the distinctive mark of the human being. Just as the intellect terminates the knowledge line and brings it to perfection, so the will begins the action line and initiates responses that can lead to human perfection in practice.

In the bridge between intellect and will at the top of Figure 6 an operative habit labeled " a " has been added to the entitative habit " s." The latter, as already noted, stands for science or the sciences, the health of the intellect, one might say, in its ability to reason correctly and come to the truth in a systematic way. The " a," on the other hand, stands for art or the arts (technē), the " know how " that applies knowledge to practice and points out the right thing to be done, here and now, to achieve an intended result. The difference between this operative kind of knowing and the speculative understanding of the pure sciences can be illustrated in the differences between the engineer and the physicist and between the biologist and the medical doctor. Engineers and internists are good engineers and good internists only to the extent that they choose the right means to achieve a desired result, whether

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this be designing a computer that works properly or restoring health to a dysfunctioning organ. In both cases, it should be stressed, to refer to their operating knowledge as art is not to remove it completely from the sphere of scientific knowing. Both engineering and medicine are also commonly referred to as sciences, but the sense then is that they are practical sciences--practice disciplines concerned with knowing in order to do and, in the final analysis, with doing more than with knowing. And this same practical component is found in all the arts and crafts, from the art of politics and the art of rhetoric to architecture and the fine arts that make our world a more beautiful place in which to live.

Human Perfectibility

One may now ask the question, and it has been asked for centuries, whether there is any kind of knowledge that enables one to become, not a good artist or a good engineer or a good doctor, but simply a good person, a good human being precisely as human? Attempts to answer that question give birth to the special discipline known as ethics or moral philosophy. The art of living well, that is, of living reasonably and bringing all of one's natural powers to their proper fulfillment, is the basic concern of ethics. Like engineering and medicine, this is a practical science. As Aristotle conceived it, it examines the ways in which one's operative powers can be habituated to act rightly, that is, reasonably, in the difficult situations with which one is daily confronted. For Aristotle this practice discipline has three components: ethics itself, which regulates how the individual should act to achieve personal perfection; economics, which addresses itself mainly to problems of the family and how its members can attain their proper well-being; and politics, which has a similar concern for problems of the state.

The basic insight is that man's natural powers can be perfected by operative habits in the action line just as they can by entitative habits in the knowledge line. Operative habits are acquired through repeated activity: if they advance a person's

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good and make him good they are called virtues; if they do the opposite, they are called vices. The ensemble of virtues and vices one has acquired is usually referred to as character. Through daily living not only do we develop skills and personality traits but we also develop character, and do so whether we consciously intend it or not. Virtues, or good habits of acting, are acquired simply enough--through repeated actions moderated by right reason. A person develops a good character by cultivating the cardinal virtues: prudence, justice, moderation, and courage. These become for him " second natures," as it were, habituating him to act reasonably, i.e., to control his natural passions and to give to others their due. In this way he himself becomes good, and so more fully human. The individual who fails to acquire virtue, on the other hand, and for example is repeatedly unjust in his dealings with others, inculcates a character defect and to this extent is stunted precisely as human.

The schematic diagram in the lower portion of Figure 6 repeats that in the upper portion, excepting that it now indicates the operative habits that bring man to his personal perfection through rational and voluntary activity. Notice here that prudence (p) has taken the place of art (a) in the diagram above. It is analogous to the " know-how " of the doctor or the engineer, and yet it is much wider in scope. Prudence is a habit of the practical intellect that enables one to choose wisely and well, that is, to determine the correct course of action to pursue in the widest variety of circumstances encountered in day-to-day living. It is concerned with subject matter that can pertain also to the other virtues, judging the mean between excess and defect, for example, in matters of eating and drinking. Justice (j) is a habit of the will that inclines its possessor to render to others their due. Moderation (m), sometimes called temperance, controls the impulse emotions, as seen in a temperate attitude toward food and sex. Courage (c) or fortitude, on the other hand, controls the contending or aggressive emotions, guarding against excessive anger, fear, or despair. The individual whose intellect is perfected for prudent

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decisions, whose will is disposed to be just, whose passions or emotions are under the control of intellect and will through courage and moderation, is said to have a good character. The problem of character formation, on this accounting, is essentially the problem of acquiring moral virtues such as these, and then of habituating oneself to the type of action that is conformable to their possession and continued retention.²⁷

Remember that we are discussing the idea of nature, now instantiated in that of human nature, showing how it is intelligible through the powers of the human soul (clearly the key to man's perfectibility), and so providing a norm--a natural and objective norm--for virtuous human action. Does the idea of nature, in this context, have contemporary relevance for ethics and politics? From the viewpoint of ethics itself the answer would seem to be obvious: good people, happy people, are those who have endowed their human natures with second natures, with intellectual and moral virtues, that can bring them to their fulfillment precisely as human. So let us now extend our inquiry further into the domains of economics and politics. This will enable us to inquire about the role of society in promoting virtue in its members and so bringing them to their natural perfection.

The Body Politic

A human being is never completely self-sufficient: he comes into the world dependent on parents, grows up within a family context, and requires the additional resources of city or state to reach intellectual and moral maturity. Family and state,

27 For a summary account of these moral virtues, and how each contributes to human perfection and happiness, see Josef Pieper, The Four Cardinal Virtues, Notre Dame, Ind.: University of Notre Dame Press, 1976. A fuller analysis will be found in Jody Palmour, The Ancient Virtues and Vices: Philosophical Foundations for the Psychology, Ethics, and Politics of Human Development, University Microfilms, Ann Arbor, Michigan (Ph.D. Dissertation, Georgetown University, 1984) ; also, by the same author, A Differential Diagnosis of Aristotle's Virtues and Vices, Based on a Psychoanalytic Perspective and the Theory of the Four Causes (Cross-referenced to both the Nicomachean Ethics and The Art of Politics), Washington, D.C.: Archon Institute, 1985.

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in some form or other, thus seem practically necessary for the development of a rational being: an animal rationale is by nature and instinct an animal sociale, and homo sapiens cannot help but also be homo politicus.

The family is obviously the first support system for human development. Mother and father are necessary to bring offspring into the world, and they are the normal requirement for providing nurture and sustenance during its early years of growth. Food and shelter are required for the proper development of organs and limbs, and parents normally provide these and the care their provision entails. Even more important, however, is growth in character, in learning not only to speak but to tell the truth, in practicing how to moderate one's appetites, in coming to recognize the rights of others and giving them their due. The community, and particularly the school, can provide assistance in such character formation, but the primary responsibility resides with the parents, with mother and father, who must give long and devoted attention to the task if they would achieve its goal. This requirement alerts us to one of the gravest social disorders of our times: the breakdown of family life owing to separation or divorce, the growth of one-parent families, the increasing number of " latch-key " children who are alone much of the day and lack reliable guides to the development of virtue. Small wonder that juvenile delinquency is on the increase and that alcohol and drug addiction have reached alarming proportions in our otherwise affluent communities.

Does the body politic, over and above the family, have any essential role to play in the development of virtue? Such a question is difficult to answer, but a reasonable response can perhaps be gleaned from Aristotle's teaching in the Politics, particularly in how he saw this work related to his Nicomachean Ethics and its preparatory treatises.²⁸ For Aristotle, the Politics is the second half of a subject whose first half is

28 A summary reply to this question is contained in Charles N. R. McCoy's article on "Political Philosophy" in the New Catholic Encyclopedia,, 15 vols., New York: McGraw-Hill Book Co., 1967, 11:510-516, on which much of the following exposition is based.

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the Ethics: both constitute the science of human affairs, of man's good or happiness. This happiness consists in a certain manner of life, a life of virtuous activity, which inevitably is shaped by one's social environment--the laws, customs, and institutions of the community to which one belongs. The sense of Aristotle's statement that man is "by nature a political animal " is that he only develops his full capabilities in society when this is rightly organized for his welfare. Once one knows in what manner of life human fulfillment is to be found, then and only then can one inquire into the form of government and the various social institutions that will enable it to be secured. It is this latter inquiry that raises questions about the constitution of the state, with which the Politics is principally concerned.

Politics, like ethics, is a practical science. Indeed it is the supreme practical science, because it has for its aim human welfare and happiness as a whole. It is based on the premise that man is free and is capable of governing himself, but it also recognizes that man is limited in this self-government because he is produced by nature and can perfect only the nature he has. The self that is involved in self-government is really the second nature or character man has developed, and this is determined by the virtues he has inculcated in his soul--let us now call them the political virtues: prudence, justice, courage, and moderation. If all people possessed these virtues, to be sure, government would be a simple matter. The fact is that they do not. And so politics cannot deal with the ideal, utopian state; it must address itself to very refractory material, to the common condition of men. In its practicality it must almost be pragmatic in adapting practical reason, and the law that attempts to embody it, to meeting the conditions in which ordinary human beings customarily find themselves.

Since such conditions make full attainment of virtue extremely difficult, human law cannot forbid all vices, from which good people abstain, but only the more grievous ones, from which most people should be able to abstain.²⁹ Chief

29 Summa theologiae, Pars Prima Secundae, q. 96, a. 2.

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among these are the vices that prove injurious to others, those involving injustice that make life in society difficult if not impossible. Here note an important difference between the political order and the moral order. The purpose of law is surely to make men virtuous, but the good that the law attempts to achieve is the human good of a multitude of persons, most of whom are clearly deficient in virtue. For the common good of the state, then, it suffices that citizens be only virtuous enough to obey its laws. And yet, as Thomas Aquinas clearly saw, the virtuous performances of virtuous deeds is the end at which every lawgiver aims.³⁰ The political order directs itself to a common good predicated not on force or fear of the law, but on a free advance of its citizenry to the possession of virtue. Law can provide an extrinsic help, but the common goal is attained only when a whole people develop a sense of justice, moderation, and responsibility as they attempt to bring their individual souls to proper fulfillment as human.

* * *

Let us return now to the theme with which this essay began. The concept of nature is a key concept for forging a unity between the natural sciences and the human sciences, for providing a link between knowing and doing. We have ranged over the entire world of nature, from elementary particles to the highest forms of animal life, to make essentially two points: (1) it is possible to know the natures of things, for these manifest themselves through their powers, their activities and reactivities; and (2) such natures can provide a norm against which the propriety of action is judged and so enable one to dispel the so-called naturalistic fallacy by bridging the " is " and the " ought." The idea of nature reaches its culmination in that of human nature, for man, as has been seen, is a microcosm who incorporates every element of nature in his being and whose mind can reach out and grasp the rest of Nature in its most intricate detail. But human nature is a free nature. Man's activity is not as determined from within as is that of

30 Ibid., a. 3, ad 2.

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other species; he molds his own nature, as it were, by endowing his soul with second natures that register the degree of humanity he has attained and his resulting capacity for further fulfillment and happiness.³¹

It is in such a context that we must see our political order and those who aspire to be its leaders. One who wishes to govern others should have risen above the common condition of men, above the herd, we say, not merely in the possession of fame or wealth but especially in the possession of virtue. He or she should be prudent, just, courageous, and moderate in matters of personal life, and the electorate rightly insists on that. But over and above personal prudence the political leader must have political prudence, the art of governing that sees to it that right decisions are made here and now so as to foster the common good. The most powerful adjunct to this art, as Aristotle saw it, was the art of rhetoric, with whose possession the head of the polis could persuasively urge courses of action that cultivate virtue, peace, and material well-being in its members.³² Rhetoric has fallen into disrepute in our times. The communications media unfortunately have had a deleterious effect on this art of arts: technique has supplanted substance, and no longer are logos, ethos, and pathos evident as norms by which respectable presentations can be judged. We seem above all to have lost the concern for character and value that was crucial for political action in the Greek city state. Yet, at a time when drugs and alcoholism are on the

³¹ As the reader will have noticed by now, the scope of this essay has been restricted to man's natural perfectibility, i.e., his perfectibility in the order of nature and abstracting from his de facto elevation to the supernatural order through grace. Applying the Thomistic adage, however, that grace perfects nature, one could easily extend the treatment herein to include Thomas's analysis in the Pars Secunda of the Summa Theologiae, so as to attain his ultimate goal in glory, the beatific vision.

³² Aristotle's Rhetoric is sometimes treated by scholastic authors as a part of his Organon, but it can with equal justice be regarded as a special technē that complements the political teaching contained in his Politics. For an explanation and justification of the latter way of regarding the Rhetoric, see Larry Arnhart, Aristotle on Political Reasoning: A Commentary on the "Rhetoric," De Kalb, Ill.: Northern Illinois University Press, 1981.

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rise, when the arms race threatens the destruction of the species, when pollution of the natural environment and depletion of its resources are a continuing problem, it would seem that such a normative concern, based on nature and what it means to be truly human, has become a major desideratum.

If virtuous living within the polis is a legitimate goal of the head of state and its legislators, much of the recent worry about politics and religion can be seen to be baseless. From the very foundation of our republic religion has been a most powerful force for the cultivation of morality and virtue, more effective by far than law and its enforcement. It is not religion that is to be feared; much more dangerous, it would seem, is a secular mentality that magnifies material needs, emphasizes creature comforts, distorts sex, sees " quality of life " as more important than family and children, and might even sacrifice human life if it proves too bothersome or inconvenient.

Nature is the norm. Obviously we do not possess such an exhaustive knowledge of human nature that we can prescribe every detail conducive to virtuous living. Our knowledge of reproductive biology is a good case in point. Our speculative and practical sciences in that field are especially deficient, and clearly in bioethics much work remains to be done. But, as has been said, nature is not completely refractory to our understanding, and that applies to human nature too. Perhaps the modeling techniques here proposed give some insight into the riches of that nature, and how they can and should be used to promote the common good.

William A. Wallace, O.P.

The Catholic University of America

Washington, D.C. 20064