By Brother Benignus, F.S.C., Ph.D.
The Evolutionary Hypothesis
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THE view of nature upon which the argument now in question is based is the evolutionary view. According to this view, the original living things on the earth developed from non-living matter, and all the variety of living things which have ever existed on the earth developed from these original ones. Thomistic philosophy offers no theoretical objection to this hypothesis [emphasis added]; and whether the hypothesis represents a fact is a question for natural science to answer. Let us, therefore, accept it now hypothetically in order to see where it leads us in reference to the question of whether there is purposive design in nature.
Let us suppose, then that living beings of some very simple sort – say, unicellular or even sub-cellular organisms – originally evolved from non-living matter, and that all subsequent forms of biological life have evolved, through many intermediate stages, from these first simple forms of life. The forms of life which now exist as relatively permanent types are those which, because of their kind of structure, found a way of fitting into the environment which nature supplied. They, the survivors, were not specially produced; they were simply some forms among innumerable forms impartially produced; but, by accident of a structure that jibed both within itself and with the world around it, they were kept alive while less lucky forms were destroyed. Even these survivors do not really survive; that is, they do not for any very long time, remain unchanged. They are, in fact, changing in every generation, perhaps in ways so slight as to be imperceptible, perhaps by some sudden perceptible development or mutation; in any case, their offspring are never exactly the same as they. Some of the offspring change in a lucky way; that is, they differ from their parents by having some new structure that is better adapted to their surroundings. Some others change in an unlucky direction and fit less well into their surroundings. More of the former will live long enough to produce offspring themselves, so that the whole family tree will grow faster and bigger in the direction of its more fortunate branch, until the changes in that direction become so emphasized that we call some later generation of offspring a new species. Thus the present species of plants and animals in the world have come to be what they are.
What does it all mean? Why have some of the simple living forms remained simple. Why have some developed into highly complex organisms. Why have some become plants and some animals? Were the cells which began each of these lines of evolution different from one another, or were they the same? If they were the same what caused their later differentiation? The probable answer to all these questions is environmental conditions and gene mutations. That answer explains hardly anything, but it leads to some fertile reflections concerning the emergence of the various forms of life. If the environment is the external condition of the forms of living of living beings, the internal conditions must be sought in the stuff which becomes the various forms. The cell which resists death by dividing and by becoming a multicellular organism, the cell which provides, as it were, for future contingencies by gene mutations, must have in it some mighty urge to live. The original simple forms of life, pursued their long road of self-differentiation because it was the only alternative to death; they had to evolve or die. That they have not died, that they have filled the earth with countless kinds of life, is evidence if the unthinkably rich potentiality for life which was originally locked away in them, and which the struggle to live has brought to actuality in so many different channels. Like June, nature’s urge to live keeps “bustin’ out all over”; life tries everything in order to avoid extinction.
Matter Is Urge to Live
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But what of life’s beginning? On the hypothesis which we have adopted, living things originally evolved from non-living matter. We must, consequently, locate the “urge to live” in matter itself. But can the non-living have an urge to live? It must have, for surely a becoming alive is as strongly indicative of an urge to live as is a fighting to stay alive. Then it is in matter itself that the urge to live resides. What is matter? Today the usual answer is that matter is energy; modern physics thinks in images of force and activity, rather than in images of bulk and chunk. Units of electrical charge have replaced solid particles of stuff. Every form of matter is some form of energy, and primary matter is indeterminate energy. And out of this matter or energy all living organisms have evolved. Perhaps, then, energy or matter is fundamentally, “urge to live.” However strange this may sound, it is, not un-Thomistic. St. Thomas called it matter’s appetite for the most perfect actuality attainable:
"But since, as was already stated, everything which undergoes motion tends as such toward a divine likeness in order to be perfect in itself, and since a thing is perfect in so far as it becomes actual, it follows that the intention of everything that is in potentiality is to tend to actuality by way of movement. Hence the more final and more perfect an act is the more is the appetite of matter inclined to it. Therefore the appetite whereby matter seeks form must tend toward the last and most perfect act to which matter can attain, as to the ultimate end of generation. Now certain grades are to be found in the acts of forms. For primary matter is in potentiality, first of all, to the elemental form. While under the elemental form, it is in potentiality to the form of a compound. Considered under the form of a compound, it is in potentiality to a vegetative soul; for the act of such a body is a soul. Again the vegetative soul is in potentiality to the sensitive, and the sensitive to the intellective. This is shown in the process of generation, for first in the generation is the fetus living a plant life, afterwards the life of an animal, and finally the life of man. After this no later or more noble form is to be found in things that are generated and corrupted. Therefore, the last end of all generation is the human soul, and to this does matter tend as to its ultimate form. Consequently the elements are for the sake of the compounds, the compounds for the sake of living things; and of these, plants are for the sake of animals, and animals for the sake of man. Therefore, man is the end of all generation." (Summa Contra Gentiles, III, 22.)
St. Thomas in the above passage, is not teaching evolution in the modern sense of that term, but someone coming upon the passage out of its context might well believe it to be an effort to indicate a metaphysical ground for the evolutionary process. The Angelic Doctor is teaching something that is very relevant to the problem of evolution, something which makes evolution intelligible. What he is teaching is that primary matter is appetite or urge to live and ultimately to live on the highest possible level, that is to say, as the body of man. The clear implication of this is that the first cause of the processes through which matter passes in its evolution is the end of those processes.
If, therefore, we could ask St. Thomas why matter becomes alive, he might answer: because matter is urge to live; life is the end of matter. From inorganic matter in the universe there was somehow produced living matter in at least this part of the universe, and, ever since, life has fought strenuously and successfully to keep itself in being and to attain higher levels. In order to succeed, it had to adopt a million forms whose variety staggers the imagination; but succeed it did. If, now, we ask natural science why matter became alive, only one answer can be given: it had to. Any other answer would amount to a rejection of chemistry and physics. And the answer is the same if we ask why life evolved to its present variety of forms: it had to. St. Thomas’ answer and the answer of science are in no way in conflict or disagreement; indeed, they amount to the same thing, although each states that thing from a different point of view. As always, the philosopher speaks from the point of view of action and scientist from the point of view of process. The evolution of matter is a series of actions determined by the ultimate act which is their end; it is also a series of mechanical processes produced by the series of actions. The series of processes is necessary if the series of actions is to take place and attain its end. If matter is urge to live, it must go through the evolutionary process. If it must go through the process, it is urge to live. But if matter is urge to live, should not all matter become alive? No. The scientist, speaking in terms of process, will answer that all matter cannot possibly come alive in the present order of nature, because inorganic nature supplies the conditions for life. The teleologist, speaking in terms of ends and actions, will give what amounts to the same answer: All matter does not come alive because the urge to live is not suicidal; the end of nature determines means to its own attainment, it does not swallow up its means and destroy itself. The means which nature provides in order to attain its end are the physico-chemical processes which science studies; and nature is so ordered that these processes culminate not only in life, the end of nature, but also in the inorganic conditions of life, the means to that end. In brief, mechanical and final causality are reciprocal in nature; that is the consistent Aristotelian-Thomistic position.
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