FINALITY AND INTELLIGIBILITY IN BIOLOGICAL EVOLUTION ANTONIO MORENO, O.P. Graduate Theological Union Berkeley, California I N SCIENCE AND philosophy the final cause has always ,been controversial. To biologists the problem is compli. cated, but many believe that it is impossible fo give a complete description of the phenomenon of life without taking into oonsideration the teleological aspect of it. Thus Rensch: A special feature of all living organisms is the fact that biological processes in general appear to be: 'meaningful.' They are not only appropriate to the immediate conditions, but also seem to be directed to some purpose which in individual development is only achievE:d at a relatively late stage and after many modications of form.1 Simpson's approach to this problem is shaped by the conviction that biology should attempt to answer all the questions, one of whioh is the reason for a living being's activity: "Here, ' What for '-the dreadful teleological question-not only is legitimate but also must eventually be asked about every vital phenomenon." 2 To understand how finality is realized in biology, let us first turn briefly to the nature of the final cause. The Nature of the Final CaU8e Aristotle deals with causes in the seeond book of his Physics: It is through the causes that scientific conclusions about mobile heings are demonstrated. Movement is intelligible when we discover the causes that produce it. Among the 1B. Rensch, Biophilosophy (New York: Columbia University Press, 1971), p. 107. 2 G. Simpson, Th,is Vi.ew of Life (New York: Ifarcourt, 1964), .pp. 104-108. l ANTONIO MORENO, O.P. causes, the first and most important is the final cause, which is defined as "that for the sake of which a thing is done." 3 The final cause is the motive or reason which impels the agent to operate. Motion is the vehicle by whioh the goal is attained and, consequently, the other causes exercise their causality in dependence on the final cause. Hence, Aquinas says: " The final cause is called the cause of causes, because it is the cause of the causality of all the causes. For it is the cause of the efficient ca:usality; and the efficient cause is the cause of the causality of both the matter and the form." The final cause directs, inclines, and attracts; impelled by this attraction, the efficient pushes and exercises its action. Aquinas asserts that those who reject the final cause destroy the intelligibility of science, inasmuch as they suppress the motive or first reason which justifies motion. The final cause is not the cause that executes the adion, for this is the agent's function, the efficient cause. The final cause is the reason why the agent acts. Therefore, the efficient cause presupposes the final: "The end is not the cause unless it moves the agent to act. If there is no action the final cause does not exist." 5 It is interesting to note that many biologists believe that the existence of finality destroys causality, when actually the opposite is true. For example, Simpson says: " The finalist was often the man who made a liberal use of ignaV'a ratio, . . . when you failed to explain a, thing by the ordinary process of causality, you could ' explain ' it 1by reference to some purpose of nature." 6 A simple desirn or attraction is not a cause unless it is fol.j, 3 Aristotle, Ph&sias (Trans. W. D. Ross) Book II, 3, 194b34. (Oxford, 1962). 4 Thomas Aquinas, In V Metaph., Iect. 3, n. 782. Of. Summa Theol., I, q. 105, a.5. 5 Thomas Aquinas, On the Power of God, trans. English Dominican Fathers (Westminster, Md.: Newman Press, 1952), q.5, a. l. 6 G. Simpson, The Meaning of Evolution (New Haven: Yale University Press, 1967), p. 274. FINALITY IN BIOLOGICAL EVOLUTION 3 lowed by the activity of the agent. The desire to attain the goal is called the " intention " of the action, even when the goal is not achieved, as happens in many of our actions. Failure does not destroy finality; inactivity does. For that which is first in the intention is the last to be achieved as the effect. The intention does not guarantee the success of the action. Thus Nagel: For example,. human beings are said to be goal oriented even when they fail to achieve their goal; and this is congruent with the intentional view, according to which an action is goal oriente:d if it is undertaken for the sake of some intended goal, whether or not the goal is reached. 7 Since it belongs to the intention of the action, not to the action as such, the final cause cannot he measured or observed. It is the action that we measure. This is a major reason many biologists ignore finality. Existence of the Final Cause Teleology is part of the human experience: we are aware of the existenoe of the final cause when we reflect on our own actions. By mere introspective observation we realize that we initiate an action in order to attain a. goal. This human teleology is why we ascribe finality to biology. As Simpson observes: "We do know, however, that pul'poses peculiar and arising within organisms exist as one of the great marvels of life. We know it ,because we form purposes ourselves." 8 Human teleology haiunts us whenever we study living organisms. We ascribe fina.lity to living beings 'because we detect similarities between the processes of t:hese organisms and ourselves. Does teleology exist in the living? Aristotle not only asserts its existence hut remarks that it is absurd to 1 E. Nagel, Teleoiogy Revisited and Other Essays in the Philosophy and History of Science. (New York: Columbia University Press, 1979), pp. 278279. s Simpson, 'I'his Yiew of Life, p. 175. 4 ANTONIO MORENO, O.P. deny it. 0 Aquinas, following Aristotle's lead, notes that what most strongly demonstrates that nature acts for the sake of something is this: in the operation of nature a thing is always observed to become as good and as suitable as it can be. 1 ° For example, the human foot develops in a certain way so that it may he suita:ble for walking, and this development is always uniform and fixed. Regularity suggests the existence of finality; indifference destroys it, since from indifference nothing follows. " Whenever there is a determinate principle and a determinate order of procedings, there must be a determinate end for the sake of which other things come to be." 11 This reasoning allows Aquinas to find similarities between nature and the human way of acting: " Therefore, the agent that acts with nature as its principle is just as much directed to a definite end, in its action, as is the agent that acts through intellect as its principle." 12 In the last analysis, however, the existence of finality cannot be demonstrated in the strict sense.13 For the final cause is not a conclusion we observe hut the first principle of action, and principles cannot be demonstrated. Nature suggests and reveals its existence in a way that makes the living processes more intelligible. This is what we intend to prove by examining a few concrete examples taken from >biology. 1 1 Physics, II, 8, 199b 27. .Aquinas, Commentary on Aristotle's Physios, trans. Richard Blackwell, Richard Spath and Edmund Thirkel (New Haven: Yale University Press, 1963), Book II, lect. 12, n. 252. 11 Ibid., Book, II, lect. 13, n. 264. Cf. Summa, Oontro, Gentiles, trans. Vernon J. Bourke (Garden City, N.Y.: Image, 1956), Book III, Chapter 2, n. 8.: " If an agent did not incline toward some definite effect, all results would be a matter of indifference for him." 12 Ibid. and Oontro, Gentiles, Book III, ch. 2, n. 6. 13 Ramirez, S., De Hominis Beo,titudine, Vol. 1, p. 211: "Quod quidem principium est analyticum seu per se notum, et ideo directe non potest nee Poteat tamen dedebet demonstrari, quia neque indiget demonstratione. clarari, exponendo terminos ejus per discursum impropium seu mere explicativum; et indirecte demonstrari per reductionem ad absurdum, si ejus veritas negaretur. (Biblioteca de Teologos Espanoles, Salamanca, 1942). Cf. Aquinas, In III M etaph., lect. 5, nn. 389-390. 9 Aristotle, 10 Thomas FINALITY IN BIOLOGICAL EVOLUTION 5 Examples of Finality in Biology For plants water is a necessary element for survival. Hence all desert plants must cope ,with dryness. This is the way they do so: The seeds of all desert annuals, for instance;, are quiescent until enough rain has fallen so that the desert soil holds enough water for them to grow, flower and ripen their seed . . . But there are also the desert plants called phreatophytes, which reach down with their roots to underground reservoirs. Thesl': do such a remarkable job of seeking out permanent water supplies that man has learned to follow them and dig wells where they grow. The me,squite is such a water indicator-it will grow only where there is permanent water within 30 feet of the surface-and most wells in California desert have been dug between mesquite shrubs .... Still other desl':rt plants have adapted to drought conditions by making their root system so efficient that the last vestiges of water in the most minute quantities can be reached and exploited. The creosotl': bush is one of these, with roots that penetrate far and wide. After a long rainless period, however, these plants, like many others, will begin to suffer from drought. But the American pygmy cedar can forego soil water entirely: amazingly l':nough,. it is able to live on the water vapor of the air alone, replenishing its supply each night, when even on the desert the air may become nearly saturated. 14 Is there finality in the processes? If finality is ascribed to them, they become more intelligible: the plants need water, without which the plants die. Hence all these extraordinary living activities are for the sake of a purpose-the goa.l of attaining water. Water is therefore the goal of all these remarkable adaptations, which have developed in a variety of ways according to the actual conditions of the environment and the different kinds of plants. The ultimate end is survival, which cannot be achieved without water, which in its turn is obtained by the variety of different ways described above. The harmony between means and ends is perfect. If purpose is removed from these living processes, then the alternative is that 14 The Plants (New York: Time-Life Books), p. 80. 6 ANTONIO MORENO, O.P, the plants survive by chance; it happened that water was the effect obtained by the plants' activities hut not the 1goal intended. Without teleology part of the explanation is missing, since we do not know why it happened. Let us analyze .another example: rthe healing of wounds. When you cut your finger, a fluid discharge covers the exposed region and forms a film over it. The film includes fibrous strands which stretch across the wound and probably provide guidelines for the migrating cells which form the new tissue. After the formation of the fibrous film, some skin cells become detached and are then free to wander about. This is a controlled migration of individuals-which is something like the movement of a herd of animals. Deeper lying cells migrate to replace those that were destroyed by the cut. New capillarie.s are formed. At the same time, other cells advance from the edges of the wound, perhaps following the fibrous guidelines, and bridge the surface of the wound. Bit by bit the tissue is restored to normal. There is a final act in the healing process. The tissues of a wound not only grow when needed; they stop growing as soon as healing is completed. 15 This example is remarkable, and invites us to ask this question: Is the healing of the wound intended? In other words, is the purpose of all these related steps the healing O!f the wound? If not, it happened by chance, and by chance it stops as soon as the healing is completed. Finality makes the whole phenomenon more intelligible: the healing of the wound is the purpose of the process, which is achieved by the series of steps explained and naturally stops as soon as the goal-healingis achieved. Let us now explain the last example: the way human nature fights infections. Foreign substances are always slipping through the body's outer defenses and attacking its internal systems. Such attacks can be troublesome when the foreign agents work their way into the bloodstream. In such cases, the entire organism may be endangered. 15 The Oell (New York: Time Incorporated), pp. 106-107. FINALITY IN BIOLOGICAL EVOLUTION 7 Fortunately, there is a second line of defense which stands ready to repel any invaders. This is a white blood cell called the lymphoid cell ... They respond aggressively to invaders, producing a difl'ere;nt weapon for each type of intruder-a kind of magic bullet designed to hit a specific target. . . . These natural identification tags, molecules with characteristic structures,. are known as antigens .... It is known that each antigen stimulates the lymphoid cells to manufacture proteins on a large scale and to dump them into the bloodstream. It is these proteins that lead the body's attack on invaders ..... It takes usually from four to ten days for the body to prepare its defenses. These made-to-order molecules belong to a class of substances called antibodies. These substances pour into the blood stream, attack the invader germs and cause a chemical change in the germs, which make them vulnerable to the next step. This step is accomplished by a crew of wandering scavenger cells called the phagocytes. The phagocytes attack specific types of germs which have been tagged by the antigen-antibody interaction and eliminate the invaders by swallowing them whole. In most cases, the combined offensive by the antibodies and the phagocytes continues until the: infection subsides .... During the course of a lifetime the average person may be exposed to as many as 100,000 different antigens-yet his body will dewith each invader. 16 velop antibodies to identify and Is this biological activity teleological? The purpose of these prooesses is the destruction of the infection. It may happen that these extraordinary, related processes occur by chance. But if teleology is accepted, then the defense of the organism from infection makes more sense, for the purpose of this remarkable activity is the preservation of the person's life and health, which cannot be achieved unless the infection is destroyed, which in its turn requires the manufacture of concrete antibodies and so forth.. Antibodies are the means by which health-the goal-is achieved. This is a teleological explanation. This explanation does not destroy causality; on the contrary, it is the reason why the whole process takes place. All these examples suggest the existence of a relationship between effects and causes, .between means and ends, between 1e Ibid., pp. 169-171. 8 ANTONIO MORENO, O.P. the activity of the agent and the purpose achieved by that activity. The purpose of one activity is to heal the wound; the purpose of the activity of the plants in the desert is to attain water; and the purpose of :fighting human infections is the health of the individual affected. Finality is the expedient solution of the question" Why?" which we ask spontaneously to make these examples more meaningful. The Hypothesis of Evolution We have investigated the activity of living beings as we observe them now. But for biologists, the main conoern lies in the becoming, in the process; evolution is the key that unlocks the mysteries of living beings. In art, the purpose of the artifact explains why it is as it is. If we ohs,erve that the purpose of a plane is to fly, it is obvious that its becoming, the making of the plane, is essentiaily related and subordinated to the flying aotivity. This is art. We may also ask the same question of living beings. Can we postulate, or at least suggest, that evolution took place for the sake of the biological activity we observe now? In other words, if the effect of evolution is teleological, can we suggest or even imply that evolution itself is also teleological? For example, human nature manufactures antibodies to fight infections. Can we therefore suggest that evolution " intended " their production? W1e accept this philosophical principle: " The becoming is for the sake of the being; it is ordered to the being. So those things have to be ascribed to the (Joming which are ascribed to the being." 17 Becoming and the being-evolution and the effect of evolution-are correlated. Comparing m1t and nature in the Physica, Aristotle suggests: Now intelligent action is for the sake of an end; therefore the na- ture of things also is so. Thus if a house, e.g., had been a thing made by nature, it would have been made in the same way as it is now by art; and if things made by nature were made also by art, they would come to be in the same way as by nature. . . . If, 17 Thomas Aquinas, Summa Theol., I, q. 45, a.4. FINALITY IN BIOLOGICAL EVOLUTION 9 therefore, artificial products are for the sake of an end, so clearly also are natural products.18 These arg:uments may justify the hypothesis of the existence of teleology in evolution, hut to verify this hypothesis we must now deal with the theory of ,evolution, beginning with the genetic code. The Genetic Code In order to understand the change of one species into another, it is important to keep in mind that in every chromosome, in every cell, a molecule exists that makes a mouse a mouse and a man a man: DNA. The secret of its creative diversity lies in its structure. The way in which DNA is huilt accounts for the billions of forms it can command.19 Geneticists now think that it is the order of steps of the DNA molecule which gives every gene its special character. The amount of DNA in a living organism and the complexity of the organism also seem to be somewhat oorl'lelated. In general, heredity consists in self-replication of the genetic material, or DNA, with only slight modifications from the DNA of the parents. Evolution, however, " appears to depend on the self-replicating and self-varying (mutation) string of DNA, and the self-replicating and self-varying inevitably lead to natural selection." 20 Geneticists ,contend that, although sexual reproduction reshuffles the DNA deck of cards, no new genes can be created; only various new combinations of existing genes come into Evolution, however, presupposes changes in the gene pool of a population. Mutation and natural selection are not the only factors but they are the two primary factors in the theory of evolution. The Change of Species A. change in species, then, must be the result of a change in the structure of its paJ.'lticularDNA molecule. Mutations and is Aristotle, Physics, II, 8 199a 10-15. u Evolution (New York: Life Natural Library), pp. 102-103. 20 Ibid., p. 95 10 ANTONIO MORENO, O.P. natural selection gradually change the structure of the DNA molecule. A profound change in the structure of the DNA, then, results in a new species, inasmuch as the form of the species must be in proportion ;to the new structure of the DNA. As Dobzhansky ·explains: "One thing no single mutation has done is to pToduce a new species, .genus, OT .family. This is because species differ always in many genes, and hence arise by summation of many mutations." 21 Mayr stresses this idea even more: " Species differ in hundreds or even thousands of genes. And ,each mutation will result in a slight change of the genie environment of all the other genes." 22 This leads ;to a crucial issue. How is it possible to dispose the genetic materiaJ for the superior form? Here natural selection appears to be the primary factor. This was Darwin's greatest contribution to the science of evolution. The adaptation and diversity of life and the appearance of new origanized fornns can he explained by the orderly process of change Darwin called natural selection. We feel sure that any variation in the least injurious would be rigidly destroyed. This preservation of favorable variations and the rejection of injurious variations I call natural selection. 23 Of course, now natural selection is not exactly as Darwin conceived it, for as Dobzhansky says: The selectively fit, or if you will, the fittest, is not necessarily a fellow with big muscles, or a lusty fighter, or a conquerer of all his competitors. He is rather a paterfamilias who has raised a large numbe.r of children who in turn become paterfamilias. 24 This new idea is taken up by Lerner who defines selection 21 Thomas Dobzhansky, Genetics and the Origm of Species (New York, 1964)' p. 31. :22 E. Mayr, Systematios and the Origin of the Species (New York: Dover, 1964), p. 69. 2a Charles Darwin, The Origin of Species. Quoted by F. Ayala, " A Biologist's View of Nature," in A New l!Jthic for a New l!Jarth, ed. Glenn G. Stone (Friendship Press, 1971), p. 30. 24 Thomas Dobzhansky, Heredity and the Nature of Man (New York, 1966), pp. 153-154. FINALITY IN BIOLOGICAL EVOLUTION 11 "In terms of its observable consequences as the non-random differential reproduction of genotypes." ·25 Hence natural selection is based on the fact tha1t some genotypes leavce more offspring than others. N atura.l selection enhances the development of the life of the individual and ultimately of the species. For geneticists, natural selection is not merely a process of statistical chance hut an orderly process of orderly change governed by natural laws. Certainly it is not haphazard. 26 As the geneticists say, causal relations, not caprice, prevail in nature.21 Additionally, to many geneticists, natural selection is not merely a negative force in evolution, but an element which creates new and superior structures in the DNA molecule that call forth the emergence of new forms and species. For Simpson, it is evident that seleotion has a positive and creative role, and that it is indeed the decisive, orienting, process in continuing ada:ptation. 28 For Dohzhansky: Natural selection is comparable not to a sieve but to a regulatory mechanism in a cybernetic system. The genetic endowment of a living species receives and accumulates information about the challenges of the environment in which the species lives. The evolutionary changes are creative responses to the challenges of the environment. They are not alterations imposed by the environment as Lamarckists mistakenly thought. 29 Hence evolution has not just preserved life on earth from destruction; it has created progressively more complex and adaptively more secure organizations. 30 Natural selection tends to maximiz;e the probability of the preservation and expansion o[ life. For example, bhe adaptation of plant life to a dry 25 I. M. Lerner, The Genetic Basis of Selection (New York: John Wiley, 1958)' p. 15. 26 See Thomas Dobzhansky, The Biology of Ultimate Concern (New York: The New .American Library, 1967), p. 126ff. 21 Ibid., pp. 126, 122. Cf., G. Simpson, "The of Life " in Evolution After Darwin (The University of Chicago Press, 1960), Vol. 1, p. 166. 28 Simpson, The Meaning of Evolution, p. 224. 2g Dobzhansky, The Biology of Ultimate Concern, p. 122. so Ibid., p. 120. ANTONIO MORENO, O.P. climate, as e:x;plained before, is for Dobzhansky a consequence of the crea.tive of natural selection. For example, all dese.rt plants must cope with dryness. Different plants do so, however, by different means. Some have leaves reduced to spines, others have leaves protected by waxy or resinous secretions, others shed their leaves when humidity becomes deficient, and still others germinate, grow, flower, mature seeds, all within a short span of time when water is available.31 N atuml selection can aJso generate new organs by increasing the probability. of otherwise improhahle genetic combination. For example, geneticists regard the formation of the vertebrate eye as an example of natural selection. The combination of genetic units which carries the hereditary information responsible for the formation of the vertebrate eye have never been produced by a random process like mutation-not even if we allow for the three billion years plus during which life has existed on earth. The complicated anatomy of the eye like the exact functioning of the kidney are the result of non-random proce.ss-natural selection.32 Teleology and Evolutwn Some biologists explain evolution in terms of finality, although they have different ideas of its meaning. Teleological explanations imply ,the existence of a means-to-ends ship in the system under consideration. This suggests that the system is organized and meaningful. Let us the problem. In Darwin's original theory, purpose is indispensable to his reasoning. Cassirer stresses: It is safe to assert that no earlier biological theory ascribed quite as much significance to the idea of purpose, or advocated it so emphatically, since not only individual but absolutely all the phenomena of life are regarded from the standpoint of their survia1 Ibid., p. 126. 32 F. Ayala, "A Biologist's View of Nature," in A New Ethic for a New Earth, p. 35. Ji'INALITY IN BIOLOGICAL EVOLUTION val value. All other questions retreat into the background before this one,.33 Survival value is the ultimate purpose in Darwin's theory. Teleology also appears fo cor11espond to contemporary natural selection, for the adaptation and survival of organisms is an observed fact which enhances the conservation and improvement of the species. In general terms, natural selection is teleologica.lly oriented in that it produces and maintains end-directed organs and mechanisms when the functions they serve contribute to the reproductivity and efficiency of the organism.34 " Teleological explanations imply that such contribution is the explanatory reason for the presence of the process or object in the sys,tem." 35 Hence it is appropriate to give a teleological explanation of the operation of the kidney in regulating the concentration of salt in the blood. We have a kidney because the regulation of the concentration of salt in the organism is a necessity, and therefore this regulation is "that for the sake of which" we haV'e a kidney. Thus Simpson: For many biologists, utility is proposed as the purpose of evolution. The problem of utility is the problem of teleology, whether evolution has goals or ends and, if so, what and whose those ends may be ... The: organization of organisms certainly has utility, and the evolution leading to them has that utility as a goal in a sense. That sense is, however, quite special and does not correspond with a preordained plan . . . The utility of any feature of organisms is with respect to the population of those organisms at any given time. It is not related to usefulness to any other organisms; it follows no pre-existent plan; and it is not prospective toward any future goal. The over-all and universal goal is a posteriori at the given moment and is simple survival, which involves comparative success in reproduction. 36 Emerson claims that the evolution of functions directed to33 E. Cassirer, The Problem of .Knowledge, trans. W. II. Woglom and C. M. Hendel (New Haven, Conn., 1950), p. 166. 34 F. Ayala, " Biology As An Autonomous Science," American Scientist 56, no. 3: 217. 35 Ibid., p. 214. sa Simpson, "The History of Life," p. 175. 14 ANTONIO MORENO, O.P. ward ends can be demonstrated. He calls the process " teleonomic," using the word coined by Pittendright. 37 Waddington writes " of the major problems of the ' appearance of design,' or biological adaptation." 38 For biologists adaiptation, utility, and survival seem to be the accepted ,goals of evolution. N atura.l selection as " differential reproduction " is for the sake of adaptaition, utility, and, in the last .analysis, survival, inasmuch as the non-adapted living being dies. Although teleology is part of living organisms, this is not taken to mean that purpose is to he achieved hy means of a single pre-existent plan. 39 The process is now called "teleonomic," although biologists do not totally agree on the meaning of this new term. Ayala questions the wisdom of the use of the concept of teleonomy: Should the term ' teleology ' eventually be discarded from the scientific volcabulary, or restricted in its meaning to preordained and directed processes, I shall welcome such an event. But the substitution does not necessarily clarify the issue at stake . . . It may further be that the term 'teleonomic' is commonly employed in the restricted sense of self-regulating mechanisms. There are phenomena in biology that are without being self-regulating mechanisms in the usual sense. The hand of a man, for example.40 37 A. Emerson, " The Evolution of Adaptation in Population Systems," in Ji1volution After Darwin, Vol. 1, p. 343. 38 C. H. Waddington, "Evolutionary Adaptation," in Ji1oolution After Darwin, Vol. 1, p. 386. au Simpson, "The History of Life," p. 175. 40 F. Ayala, "Teleological Explanatons in Evolutionary Biology," in Philosophy of Science 37, no. 1 (March 1970): 14. Cf. C. S. Pittendright, "Adaptation, Natural Selection and Behavior," in Behavior and Evolution, ed. A. Roe and G. Simpson (New Haven: Yale Unversity Press, 1958), pp. 390-416. p. 394: " It seems unfortunate that the term 'teleology' should be resurrected. The biologists' long-standing confusion could be more fully removed if all end-directed systems. were described by some other term, like 'teleonomy,' in order to emphasize that the recognition and description of end-directedness does not carry a commitment to Aristotelian teleology as an efficient causal principle." Actually, Aristotelian teleology is not an efficient causal principle, but the goal of this principle, as explained before. See also Simpson, This View of Life, pp. 112 and 119. FINALITY IN BIOLOGICAL EVOLUTION 16 To summarize, there are different views regarding the meaning of teleology or teleonomy ascribed to living organisms. But many biologists accept the existence of end-directed processes. Observation reveals that living organisms are oriented towards adaptation, utility, and survival. Selection is for the sake of these goals. Natural Selection a,nd Teleology: Difficulties It is difficult to explain teleologically the operation of the genes and their mutations, for mutations produce chaos and not evolution. Dobzhansky observes that the history of life is comparable to human history, since both proceed by trial and error, with false starts, yet achieving progress on the whole. The paradoxical feature of evolution is that design and chance appear ·simultaneously, a chance and design which is opportunistic and short-sighted. And yet, in the end, chaos is redressed by natural selection, harmful genes are reduced in frequency, and useful ones perpetuated and multiplied. 41 The opportunistic trait of evolution appears to .be in opposition to the classical concept of finality. Dobzhansky explains this problem with clarity. Adherents of :finalism and orthogenesis contend that, since it is quite incredible that evolution could all be due to ' chance,' one must assume that it has had a design which it has followed. The reality is, however, more complex and interesting than chance vs. design dichotomy suggest. 42 Thus, Dobzhansky, Simpson, and the majority of outstanding biologists. reject the Aristotelian concept of finality inasmuch as they identify finality with orthogenesis. Orthogenesis is defined as "evolution in a straight line." 48 Such a process would he not merely directional, but unidirectional, that is, not merely tending in some direction hut long maintaining a single di41 Dobzhansky, The Biology of Ultimate Ooncern, p. 122. p. 125. .a Simpson, The Meamng of lilvoltution, p. 131 fn.l. 42 Ibid., 16 ANTONIO MORENO, O.P. rection. 44 Naturally, biologists reject the concept of finality in a straight line. The multiplicity of ways of becoming adapted to similar environment is not in accord with hypotheses of design and orthogenesis in evolution; these hypotheses would lead one rather to expect that a single and presumably most perfect method, will be used everywhere. On the contrary, natural selection is more permissible.45 Evolution would be orthogenetic if a. rigid orientation were everywhere the rule, hut this is not the case in evolution. 46 Hence biologists reject what they believe to be the classical concept of finality. But as explained earlier this is not the Aristotelian concept of teleology-which does not imply that the goal is achieved through the rigid orientation proper to orthogenesis.. Nor does finality require achievements to be the best possible goal, as some geneticists mistakenly believe. Simpson takes up the example of the horns developed by aJJJtelopes in the Belgium Congo: none of them achieved the best possible adaptation. " It is only under the vitalist and finalist theories that one can suppose that the changes that arise are indeed just the ones needed for the best adaptation." 41 Simpson is wrong in his interpretation, for the classical concept of finality does not ,require as a goal the best possible adaptation, hut the adaptation which is possible given the concrete mutations available and the conditions of the environment. Natural selection works with these two elements: "Harmful genes ave reduced in frequency, and useful ones perpetuated and multiplied." 48 Adaiptation is neither orthogenetic nor the best but, as Simpson put it, opportunistic and continuous.49 Is it possible to have classical teleology take these traits into consideration? Let us explore the question. 44 Ibid., p. 133. The Biology of Ultimate Oonoern, p. 127. The Meaning of Evolution, p. 167. 47 Ibid., p. 168. 48 Dobzhansky, The Biology of Ultimate Oonoern, p. 122. 49 Simpson, The Meaning of Evolution, p. 224. 45 Dobzhansky, 46 Simpson, FINALITY IN BIOLOGICAL EVOLUTION 17 Opportunity and Extinction in Evolution Geneticists emphasize the opportunistic character of natural selection. Natural sele;ction is automatic, blind, and lacking foresight. It is opportunistic, in the sense that it adapts the organism to the environments existing at the time it acts, and it cannot take into account any possible changes of the conditions in the future ... The conseque;nce of this opportunism and myopia may be extinction.5<> Groping in the dark is the only way natural selection can proceed. It may lead to discovery of openings toward new opportunities for living, it may preserve and enhance life, or it may lead to extinotion. 51 This opportunistic trait of evolution is the reason why natural selection has developed a tremendous variety of living beings, which includes hundreds of distinct adaptive types. This is something observed in spite of the fact that the opportunities offered by mutations and the environment are always limited. " What can happen is always limited. Boundless opportunity for evolution has never existed . . . Possible w:ays of life are always restricted to two ways: environment must offer the oppo11tunity and a group of organisms must have the possibility of seizing this opportunity." 52 Sometimes natural selection fails, for it cannot cope with an adverse environment, or it is impotent to opemte with deleterious mutations. The consequence is extinction: The gene.ral, true cause of extinction seems to be a change in the life selection, the organism-environment integration, requiring in the organisms concerned an adaptive change which they are unable to make. 53 But even in these cases teleology does exist, for natural selecso Dobzhansky, The Biology of Ultimate Concern, p. 57. p. 128. 52 Simpson, The Meaning of Evolution, p. 161. 53 Ibid., p. 203. 51 Ibid., 18 ANTONIO MORENO, O.P. tion does not cease to stmggle for survival and for adaptation as its goals. Among humans there are many individuals who cannot cope with the circumstances " here and now " and so they die. There are tribes in the Amazon River on the verge of extinction, in spite of their life-and-death struggle for existence. Many species of animals are now disappearing, not because they do not strive for survival, hut because their opportunistic and short-sighted reactions to the " here and now " situation are insufficient to overcome adverse conditions, usually created hy man. In all these cases natural selection is a.t work. The concept of finality does not necessarily piresuppose success, hut struggle for survival, a general orientation present in evolution. As Simpson says: The changes involved do have direction and orientation, even though these were not as regular as they have usually been represented. And so, in hundreds or thousands of other cases, it seems clear that there is an orientation of some sort. 54 This orientation is not the rigid orientation of ol'lthogenesis, hut an orientation that has produced variety through the evolution of new forms of life. Evolution has achieved more than to preserve life on e.arth from destruction. It has created progressively more complex and adaptively more secure organizations. The human species has attained the peak of biological security. 55 Opportunism vs. Desi,gn Natural selection is opportunistic in the sense that it adapts the organism to the environment existing at the time it acts. " It is automatic, blind, and lacking foresight." 56 It is affected by "myopia" and it "gropes in the dark." 57 The "[h]istory 54 Ibid., p. 131. Cf. Dobzhansky, The Biol-Ogy of Ultimate Oonoern, pp. 118119: " What this seems to mean is a statement of the undoubted fact that, even in retrospect and in its totality, evolution was indeed progressive, and in this sense directional and oriented." 55 Dobzhansky, The Biology of Ultimate Ooncern, p. 129. Cf. p. 117. 56 Ibid., p. 57. s1 Ibid., p. 128. FINALITY IN BIOLOGICAL EVOLUTION 19 of life is an odd blend of the directed and rbhe random, the systematic and the unsystematic." 58 W·e faoe .a semantic problem, for to be blind is not the same as to ·be short-sighted: the one who is groping in the dark is searching for light. In other words, the question posed hy natmal selection is how to harmonize the opportunistic trait of evolution with the idea of ·a plan or design. Should natural selection he blind and lacking any vision of the future, then something else must supply that vision, for evolution does appear to follow ·an "apparent purpose," direction and order. Natural selection is creative and, much more than a sieve, creates new wonders. To suggest the possibility of design, however, does not mean there must also be a fixed plan which ignores the conditions of the environment and the mutations of genes. On the -contrary, the design must take into consideration these essential factors. It depends on them. The transformation occurs, as Huxley says, in a series of finite steps, each taking a certain period of time, the earlier ones serving as basis of the later. Natural selection cannot be 1blind, but it can be opportunistic and shortsighted in the continuum of time. It transforms nature by little, in a way similar to a work of art. Another example: automobile designs have changed continuously; the Ford model of the present year is not the famous Model T or the design of the thirties. Every new model takes a series of finite steps, ea;ch taking a, certain period of time, the earlier ones serving as basis of the later. The human design also works continuously with that which is available. Not knowing the needs of future generations, the goal and purpose is always present directing the process. The same must be true of evolution, as suggested by Aristotle, who compares the work of art and nature in this way: Thus if a house, e.g., had been a thing made by nature, it would have been made in the same way as it is now by art; and if things made by nature were made also by art, they would come to be in 58 Simpson, The M eanilng of Evolution, p. 185. ANTONIO MORENO, O.P. the same way as by nature. Each step then in the series is for the sake of the next; and generally art partly completes what nature cannot bring to a finish, and partly imitates her. If therefore, artificial products are for the sake of an end, so clearly also are natural products. The relation of the later to the earlier terms of the series is the same in both. 59 In light of these words, I dare to say that Aristotle would have accepted the existence of finality in evolution, but not ol'lthogenesis or rigid finality. Let us see now how evolution, which for some biologists cannot coexist with finality, fulfil.Is only part of all possibilities existing in nature. Natural selection depends on mutations and chance; hence, the genetic code possesses an almost infinite number of possibilities. Yet the actualization of these possibilities is restricted by the laws of statistic probability to one at a time. In other words, the nature of living beings necessarily presupposes the impossibility of the simultaneous actualization of these infinite possibilities. " What can happen is always limited. Boundless opportunities have never existed." 60 It also presupposes that a single and presumably " mo.sit perfect method " can never be achieved. It also tells us that the design is realized in a particular way, usually by following a method that is not perfect. Defects, evil, and extinction do indeed exist in nature simultaneously with teleology. This, again, is Aristotle's view. Now mistakes come to pass even in the operations of art; the grammarian makes a mistake in writing and the doctor pours out the wrong dose. Hence clearly mistakes are possible in the operation of nature also. If then in art there are cases in which what is rightly produced serves a purpose, and if where mistakes occur there was a purpose in what was attempted, only it was not attained, so must it be also in natural products, and monstrosities purposive effort. 61 will be failures in Failure and extinction do not destroy finality; only inactivity does. 59 Aristotle, Physics, II, 8, 199b 7. ao Dobzhansky, The Biology of Ultimate Concern, p. 125. 01 Aristotle, Phyaics, II, 8 199a 33-199b 7. FINALITY IN BIOLOGICAL EVOLUTION Evolution and Future Time The theory of evolution intrigues the philosopher. Where hiologists say that evolution is blind, they mean it lacks knowledge of the future. Yet the future brings the result of the processes that take place in time: " Natural selection is not prospective towards any future goal. The over-all and universal goal is a posteriori at the given moment and is simply survival, which involves comparative success in reproduction." 82 Hence survival is the goal, the purpose for the sake of which the evolutionary process takes place. Simpson, however, does not call the process teleological, but ·teleonomic, What are birds' wings for? That they are an adaptation to flying is a proper answer and partial explanation near the descriptive level. Further explanation is historical; through a sequence of configurations of animals and their environments wings became possible, had an advantage function, and so evolved through natural selection.83 Here a telenomic prrocess describes the history of the biological aotivity hut does not mention explicitly the word time. Emerson, however, introduces time in evolution and explains how biological time involves a feedback mechanism. He hints that the evolution of functions directed towards ends can be demonstrated: "Effects quite commonly precede the repeated ca.use in time ·and obviously are ahle to modify causes by means of feedback mechanisms." 64 He proceeds to explain how elaborate and complex evolution is: The circularity of cause and effe:ct-with effects often influencing repeated causes-enables mechanisms to evolve that are directed toward future function. Natural selection is some.times thought to operate without ' foresight' or at least to be ' shortsighted.' It is true that adaptations to oft-repeated events are more obvious, but 62 Simpson, "The History of Life," in E'oolution After Darwin, Vol. 1, p. 175. 68 Simpson, Thi8 View of Life, p. 135. "Adaptation in Population Systems," in Evolution After Darwin, Vol. 1, pp. 338-339. 64 Emerson, ANTONIO MORENO, O.P. rare e;vents repeated only after the lapse of many years can also be shown to influence selection pressures ... For example, antibodies against completely new protein poisons can be generated by cells and tissues. All of this means that the organic systems incorporate time dimensions and that end-directions are; apparent in ontogenetic and phylogenetic time. Pittendright refers to such end-directedness as teleonomy, without implying Aristotelian teleology as an efficient causal principle. 65 (Of course, Aristotelian teleology is not an efficient causal principle, but rather the goal that explains why the efficient cause is acting.) But, going back to the previous quotation, Emerson emphasizes the fact that the effect of a process often appears much later: in the case of antibodies, from four to ten days; in the case of changes in species, millions of years. How is that possible without foresight? By chance? Time must be incorporated into the evolutionary process, as Waddington clearly asserts: The essential feature of an evolutionary theory is the suggestion that animals and plants ... have been brought to the present condition by a process extending through time, and were not designed in their modern form.66 This means that a.daprtation and survival require a continuous change that takes place in time. Therefore: " Biological processes ... seem to be directed to some purpose which in individual development is only achieved at a relatively late stage and after many modifications 0£ form. 67 Teleological Evolution and the Need of a Planner The philosopher who investigates how living organisms adaipt themselves to the environment sees that they do not do it consciously. natura,l selection presupposes a means-toend relationship in the system, then :who determines the end, n 65 Ibid., p. 341. ss C. H. Waddington, "Evolutionary Darwin, Vol. 1, p. 382. 67 Ren.sch, Biophilosophy, p. 107. Adaptation," in Iilvoliitioii A.fte1· FINALITY IN BIOLOGICAL EVOLUTION 28 who decides the means, and who knows the relationship between ends and means? 68 For example, plants in the desert store water to avoid perishing. By storing this precious liquid plants pireserve them·selves and the species. Yet how do plants know they have to store ilt? It is remarkruble to observe the following hierarchical subordination of means