Grounding human values in evolutionary theory
'Debating Darwin: Adventures of a Scholar'
July 27, 1999
(CNN) -- University of Connecticut professor emeritus of history John C. Greene has turned a longstanding dialogue with two renowned evolutionary biologists into a new book.
In "Debating Darwin: Adventures of a Scholar," Greene, a leading figure in evolutionary ideas, discusses what sparked his interest in the history of evolution and evolutionary thought, and how he came to know 20th-century evolutionary biologists Ernst Mayr and Theodosius Dobzhansky.
In her challenging book Evolution as a Religion, Mary Midgley declares:
The theory of evolution is not just an inert piece of theoretical science. It is, and cannot help being, also a powerful folktale about human origins.... Facts will never appear to us as brute and meaningless; they will always organize themselves into some sort of story, some drama. These dramas can indeed be dangerous. They can distort our theories, and they have distorted the theory of evolution perhaps more than any other. The only way in which we can control this kind of distortion is to bring the dramas themselves out into the open, to give them our full attention, understand them better and see what part, if any, each of them ought to play both in theory and in life.
She dedicates her book "To the Memory of Charles Darwin Who Did Not Say These Things." Alas, Darwin did say some of these things, but he was a very great scientist and an admirable man for all of that.
Our starting point, however, is not Charles Darwin but rather some remarks of Alexandre Koyrť about the divorce of science from philosophy and, more generally, from the search for meaning and value that accompanied the seventeenth century revolution in physics and cosmology. The substitution of the mechanical view of nature for Aristotle's world of forms and qualities involved, says Koyrť, "the destruction of the Cosmos", the disappearance of "the conception of the world as a finite, closed and hierarchically ordered whole." In its place science erected an indefinite and infinite universe in which all the components of nature were placed on the same level of being, governed by the same laws. This, in turn, involved "the discarding by scientific thought of all considerations based upon value-concepts, such as perfection, harmony, meaning and aim, and finally the utter devalorization of being, the divorce of the world of value from the world of facts."
But although the mechanistic view of nature may seem by hindsight to have implied all that Koyrť describes, in practice it was not pushed to any such drastic conclusion. Physical nature may have been stripped of Aristotelean forms and qualities, but they were retained intact in the organic world. Robert Boyle explained the origin of forms and qualities in the physical world in terms of the motions of atoms, but it would be another two centuries before Darwin attempted to explain their origin in the organic world by natural causes. For Newton and most of his contemporaries nature was still a hierarchically ordered whole, a framework of stable structures fitted as a stage for the activities of intelligent beings, whether on this planet or in other regions of space. Matter was regarded as designed to provide a theater for life, and the lower forms of life were viewed as subservient to the needs of the higher.
For this view of nature and natural science the metaphor of nature as a machine seemed entirely appropriate. The word "mechanical" in the phrase "mechanical view of nature" had two different but related meanings, as E. J. Dijksterhuis has noted. On the one hand it meant "reducible to the principles of mechanics", the science of bodies acted on by forces. On the other hand it meant "like a machine", the operation of which could be explained by mechanical principles. The celestial machine, Kepler wrote to von Hohenburg, "is to be likened not to a divine organism but rather to a clockwork ..., insofar as nearly all the manifold movements are carried out by means of a single, quite simple magnetic force, as in the case of a clockwork all motions [are caused] by a simple weight. Moreover [Kepler added] I show how this physical conception is to be presented through calculation and geometry."
To say that events in physical nature were reducible to the mathematical rules of the science of mechanics was one thing. It implied nothing concerning the origin of those rules or the significance of the mathematical physicist himself. But to say that nature was a machine was quite something else. A machine is an artifact, designed for some purpose. It presupposes an intelligent designer. And indeed Kepler and Galileo believed that the world machine had such a designer. For them nature was the work of a "divine Artificer", and the science of nature was the divinely appointed task of human artificers whose minds had been created in the image of the Divine Mind. Through mathematical-experimental science, they believed, the natural philosopher would be led up through nature to nature's God and thus to a knowledge of his duty toward God and his fellow human beings. Through science, moreover, mankind would attain to that dominion over nature which their Creator had intended for them. Thus, through the metaphor of the machine, human beings became participators with God in the intellectual pleasures of mathematical physics and in the practical work of subduing nature to divine purposes. The universe might be infinite and the atoms of matter all on the same level, but matter was subservient to life and life to rational existence. As for science, it was increasingly regarded as the supreme human manifestation of divine reason and the surest road to useful knowledge, including knowledge of the Creator's existence and attributes and consequently of human duty and destiny. All this was implicit in the metaphor of the world machine.
All this, too, was called into question when the mechanical view of nature was extended to embrace not only the inorganic but also the organic world, a development that began when Descartes undertook to derive the present state of nature from previous states of the system of matter in motion through the operation of the laws of motion. This Cartesian enterprise was so bold, so appealing to the speculative intellect, that it was soon extended from astronomy and cosmology to geological transformations on the Earth's surface and thence, beginning with Erasmus Darwin and Jean Baptiste de Lamarck, to the origin and development of living forms.
The idea of extending the law-bound system of matter in motion to embrace the organic world seemed perfectly natural to those who proposed it, but the project had unforeseen consequences. It introduced foreign elements into the mechanistic world viewóideas of progress, levels of being, and the likeóand thereby undermined the notion of nature as a machine. Animals could be thought of as automataóDescartes had already suggested thisóbut the idea that machines could evolve from simple to complex forms (including human beings) without the aid of a designing intelligence seemed preposterous. Both Lamarck and Erasmus Darwin felt compelled to postulate a "sublime Author of nature" (Lamarck), a "Cause of causes" (Erasmus Darwin), to explain the ability of animals to respond to the challenge of environmental change by developing new faculties and organs. The function of this supreme being, however, was not to create new organic forms by almighty fiat but rather to design the system of matter in motion in such a way that it would generate the living from the non-living and improve organic forms gradually through the operation of natural causes. Evolutionary theory led, not to atheism or agnosticism, but to evolutionary deism. But there was as yet no appealing metaphor to dramatize the conception of nature as a self-perfecting process of progressive improvement capable of giving rise to the scientist himself, nor was there as yet any scientifically credible "mechanism" (a word derived from the mechanical view of nature) to account for the changes of organic form disclosed in the fossil record.
It was Charles Darwin who coined the master metaphor that eventually dominated evolutionary thinking. Having decided to adopt the transmutation hypothesis shortly after his return from the voyage of the Beagle, Darwin began the search for the natural means by which populations of organisms were modified and kept adapted to changing circumstances. Finally, in the fall of 1838, after reading Thomas Malthus' famous Essay on the Principle of Population, Darwin hit upon the idea of a general organic struggle for existence in which those members of a species which happened to possess traits favorable to survival in their particular circumstances would be most likely to reach reproductive age and hence would spread those traits through subsequent generations, thereby gradually changing the character of the population. Casting about for a suitable name for this process of variation, population pressure, differential adaptedness, differential survival, and differential reproduction, Darwin chose the term "natural selection", in order, as he said, to "mark its relation to man's power of selection" in producing new breeds of plants and animals.
There was, of course, no selection in nature. Selection implies intelligent choice, of which nature knows nothing. What Darwin called natural selection might better have been called differential reproduction through the luck of the hereditary draw. Why, then, did Darwin choose a metaphor implying intelligent choice to designate a complex set of processes involving random variation, population pressure, and differential survival to reproductive age? He did so, first, because the analogy to the selection practiced by plant and animal breeders served him well, both as a research tool and as a method of making his theory intelligible to fellow scientists and to the general public. But Darwin seems to have had another reason as well, a reason connected with his evolutionary deism. His transmutation notebooks, his essays of 1842 and 1844, and the Origin itself all show that Darwin regarded what he called "natural selection" as a set of processes designed by the Creator to produce adaptation and improvement in the organic world. In the essays of 1842 and 1844 Darwin even personified natural selection, asking his readers to imagine "a Being with penetration sufficient to perceive differences in the outer and innermost organization [of plants and animals] quite imperceptible to man, and with forethought extending over future centuries to watch with unerring care and select for any object the offspring of an organism produced under the foregoing [environmental] circumstances." Darwin could see no reason why such a being could not "form a new race (or several were he to separate the stock of the original organism and work on several islands) adapted to new ends." "As we assume his discrimination, and his forethought, and his steadiness of object, to be incomparably greater than those qualities in man," Darwin continued, "so may we suppose the beauty and complication of the adaptations of the new races and their differences from the original stock to be greater than in the domestic races produced by man's agency.... With time enough, such a Being might rationally.... aim at almost any result." Darwin was careful to say that this master Being was not the Creator Himself, but the powers he ascribed to it made it at least the vicegerent of the Creator.
In Darwin's Origin of Species there is no explicit mention of the master Being, but he lurks behind the scenes in Darwin's description of natural selection as "daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life." The products of this constant, rigorous scrutiny, Darwin observed, "bear the stamp of a far higher workmanship" than those of "feeble man" in his role of plant and animal breeder. Note that, in Darwin's view, the variations "preserved" by natural selection are not merely good in the sense that they promote survival to reproductive age. They are "improvements". Darwin's Origin abounds with "improvements" produced by natural selection. "The modified offspring from the later and more highly improved branches in the lines of descent," he wrote, "will.... often take the place of, and so destroy, the earlier and less improved branches. Hence all the intermediate forms between the earlier and later states, that is between the less and more improved state of a species, as well as the original parent-species itself, will generally tend to become extinct."
The influence of the analogy to artificial selection and of Darwin's evolutionary deism is evident in these passages. The variations selected by a plant or animal breeder are improvements from the point of view of the breeder because they move the stock in the direction desired by the breeder. But in nature there is no desired or intended direction of change unless one postulates a master Being who has such a direction in mind. From the point of view of the organism concerned it is doubtless good to survive and reproduce, but to consider the organisms that survive and reproduce as "improvements" on those that do not is to introduce value judgments supposedly outside the domain of science. Is the tapeworm an improvement on its ancestors that had a more complicated structure? Is the modern horse an improvement on Eohippus? A standard of comparison would seem to be required, and, as Darwin himself conceded in his correspondence with Joseph Dalton Hooker, the intuitive standard of comparison is man himself. If human beings are considered higher than amoebas and chimpanzees and if the fossil record seems to indicate an overall succession of forms leading eventually to human beings, organic evolution may be described as a process of progressive improvement, however haphazard and erratic. But without the fossil record and without the assumption that man is the highest organism on earth what reason is there to think that differential reproduction of organisms happening to have traits favorable to survival will produce improvement in the organic world?
To Charles Lyell it seemed evident that the improvement attested by the fossil record must have its source outside of nature, since nothing in Darwin's theory of natural selection seemed to require it. Darwin, however, was convinced that his theory did imply progressive improvement in the long run, although not in every instance of organic change through natural selection. He explained his position as follows in a letter to Lyell:
.... every step in the natural selection of each species implies improvement in that species in relation to its conditions of life. No modification can be selected without it be an improvement or advantage. Improvement implies, I suppose, each form obtaining many parts or organs, all excellently adapted for their functions. As each species is improved, and as the number of forms will have increased, if we look to the whole course of time, the organic condition of life for other forms will become more complex, and there will be a necessity for other forms to become improved, or they will be exterminated; and I can see no limit to this process of improvement, without the intervention of any other and direct principle of improvement. All this seems to me quite compatible with certain forms fitted for simple conditions, remaining unaltered, or being degraded. If I have a second edition, I will reiterate `Natural Selection', and, as a general consequence, Natural Improvement.
Darwin's Origin did indeed have a second edition (and a third, fourth, fifth, and sixth), and Darwin continued to the end to insist that the apparent improvement in organic forms disclosed in the fossil record was a necessary long-run consequence of random variation, population pressure, and differential survival to reproductive age. In the sixth edition, as in the first, these processes were represented as constituting "laws impressed on matter by the Creator" and as working "by and for the good of each being", with the result that "all corporeal and mental endowments will tend to progress towards perfection." What better metaphor could Darwin have chosen to designate these agencies of progressive improvement than the term "natural selection," evocative as it was of the benevolent selectivity of the improver of domestic stocks? True, nature's selection was much slower, much more erratic and wasteful than man's, but its superior workmanship was evident in the "endless forms most beautiful and most wonderful" it had produced. The struggle for existence was harsh, but Darwin found consolation in the belief "that the war of nature is not incessant, that no fear is felt, that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply." Natural improvement, although costly, slow, and spasmodic, was, happily, inevitable. Having produced the human species, natural selection (aided by the inherited effects of mental and moral training) would, Darwin hoped, eventually evolve creatures who would look back on him and Lyell and Newton as "mere Barbarians". In Darwin's view, natural selection was no mere mechanism of organic modification and co-adaptation. It was also the Great Improver, blind but powerful and inexorable. It had, said Darwin, elevated man to "the very summit of the organic scale" and had thereby given him "hope for a still higher destiny in the distant future."
Darwin's metaphor had taken on a life of its own. Natural selection had become a being with many of the attributes of deity. Its works were manifold, like those of the Biblical Jehovah. Its power was awesome, conferring life and death, creating new and ever more complex organic forms, separating the wheat from the tares, rewarding the efficient and punishing the ineffectual, giving hope of ultimate progress to those who believed in its power and kept its commandments. Nature, said Thomas Henry Huxley, was a great university in which all mankind were enrolled. Those who studied her ways, who learned and obeyed the laws that govern men and things, would be rewarded generously. Nature would be their ever-beneficent Mother, they her ministers, mouthpieces, and interpreters. But those who remained ignorant of her laws would be "plucked", i.e. flunkedó"and then you can't come up again. Nature's pluck means extermination."
Huxley eventually parted company with those who looked to nature's processes for the eventual solution of human problems, but Darwin held fast to his faith in the beneficent power of natural selection despite his growing doubts about evolutionary deism. "I could show fight on natural selection having done and doing more for the progress of civilization than you seem inclined to admit," he wrote to William Graham in 1881. "The more civilized so-called Caucasian races have beaten the Turkish all hollow in the straggle for existence. Looking to the world at no very distant date, what an endless number of the lower races will have been eliminated by the higher civilized races throughout the world." For Darwin natural selection, aided and abetted by the inherited effects of mental and moral training, had become the guarantor of human progress, the hope of mankind.
More than three quarters of a century intervened between the publication of Darwin's Origin of Species and the general acceptance by biologists of the concept of natural selection as the centerpiece of evolutionary theory. In the interim, evolutionary theorizing was dominated by non-selectionist theories of orthogenetic, neo-Lamarckian, or saltationist-mutationist character. With the revival in the 1930s and 1940s of the idea of natural selection in the so-called "modern synthesis", however, there was an efflorescence of metaphorical language seeking to give value and meaning to evolutionary processes and to the science of evolutionary biology. Gone, for the most part, was the evolutionary deism that had sustained Darwin throughout much of his scientific career. Most of the champions of the modern synthesis were agnostics or atheists violently opposed to any suggestion of theism, vitalism, or teleology in nature or in natural science. For them the meaning of evolution had to be found in the evolutionary process itself, but without imputing any aim or purpose to that process. Scientific explanations, they insisted, must be "mechanistic".
Sir Julian Huxley's difficulties in pursuing this non-theistic, non-teleological search for meaning and value in evolutionary processes are described in a later essay. Like Darwin, Huxley held that evolution was progressive in the long run, but whereas Darwin had been supported in this belief by nineteenth-century optimism, by the analogy of natural selection to artificial selection, and by faith in the beneficent effects of competitive struggle, Huxley could find no vindication of evolutionary progress in any of these sources. By the 1930s, after a world war, a great depression, and the advent of Fascism and Nazism, many people had come to doubt the inevitability of progress. The analogy between natural selection and plant and animal breeding had helped give rise to eugenics, but the eugenics movement had been rendered increasingly suspect by new discoveries in genetics and by Hitler's eugenic experiments. As for competitive struggle among individuals, tribes, nations, and races, Huxley had no stomach for laissez-faire political economy or for military and racial conflict. Biologists, he said, must give up the idea "that natural selection and the adaptations it promotes must be good for the species as a whole, for the good of the group undergoing adaptive radiation, or even that it must promote constant evolutionary progress."
Natural selection [he concluded], though.... like the mills of God in grinding slow and grinding small, has few other attributes that a civilized religion would call Divine. It is efficient in its wayóat the price of extreme slowness and extreme cruelty. But it is blind and mechanical; and accordingly its products are just as likely to be aesthetically, morally, or intellectually repulsive to us as they are to be attractive.
In this passage Huxley echoed Darwin's occasional misgivings about "the clumsy, wasteful, blundering, low, and horribly cruel works of nature", but whereas Darwin had been prepared to trust to natural selection and the inheritance of acquired characters for the eventual improvement of humanity, Huxley declared emphatically that the direction of evolution must be taken over by human beings, whose responsibility it was to develop "a ratonal applied biology".
But if "natural selection" was no longer a satisfactory metaphor for the processes generating improvement in the organic world, what figures of speech were to be substituted in order to give meaning to evolutionary processes? The answer, Huxley discovered, was to personify life and to depict its adventures in the struggle with environing circumstances, its opening up of ever new possibilities, its growing independence and control of the environment, its gradual acquisition of self-consciousness, purpose, and rational control in its human phase.
Living substance [wrote Huxley] demonstrates its improvement during evolution by doing old things in new and better ways, by acquiring new properties, by organizing itself in new forms, by increasing its efficiency and enlarging its variety.
This personification turned out to be Huxley's basic figure of speech. He defines improvement, advance, progress, higher, and lower in terms of life's progressive realization of its inherent potentialities. Natural selection, he notes, "can only produce results which are of immediate biological advantage to their possessors ... in relation to the particular situation of the moment, hence it often leads life into "blind alleys", from which there is no "evolutionary escape." Yet paradoxically, natural selection "operates with the aid of time to produce improvements in the machinery of living" which enable living substance to find its way onward and upward. Thus, life achieves its triumphs and realizes its potentialities both despite the short-sighted operations of natural selection and because of them. Natural selection, writes Huxley, gives life increased efficiency in dealing with the "challenge" of the environment and thereby leads it into "regions of new evolutionary opportunity".
Each new deployment, after steadily advancing over its new terrain, comes to an impasse. There is sometimes a path out of the impasse, but it is generally a devious one; it is through its twists and turns that life finds its way into a new field of maneuver; and this marks the beginning of another distinct step in progress.
The religious thrust of Huxley's evolutionary biology became explicit in his popular exposition of evolutionary science entitled Evolution in Action (note the personification). Biological evolution was now linked to cosmic evolution at one end and to human evolution at the other to form a continuous chain of evolutionary progress, "a one-way process in time; unitary, continuous, irreversible; self-transforming; and generating variety and novelty in its transformations." Evolutionary science, the science of the entire process, was disclosing the destiny of man on earth, namely, "to be the agent of the world process of evolution, the sole agent capable of leading it to new heights, and enabling it to realize new possibilities."
I shall probably be attacked for going beyond the boundaries of science [Huxley added]. But I am sure that I have been right in formulating general conclusions of this sort. Only so can one hope to have them investigated, and general conclusions about man's origin and destiny are of importance, especially in an age of doubt and transition like the present.In Julian Huxley's writings the transition from evolutionary biology to a new secular religion styled "evolutionary humanism" was carried to completion.
Not all of the champions of the modern synthesis have been as open as Huxley in acknowledging the religious aspect of their devotion to evolutionary biology, but most of them, especially those who reject religious and philosophical approaches to the problem of human duty and destiny, manage to smuggle in by way of simile and metaphor the elements of meaning and value that their formal philosophy of nature and natural science excludes from consideration. Thus, Ernst Mayr, although he insists that evolution by natural selection is a "purely statistical phenomenon", describes the phenomenon in language suggesting direction, purpose, striving, success, and failure. Reproductive isolation between species is described as "a method guaranteeing evolutionary success". Natural selection, Mayr tells us, improves adaptation continually until it appears "as perfect as if it were the product of design". It "remodels" proteins "in order to improve interactions". It produces "ever increasing improvements in mechanical efficiency" and gives direction to evolution. It "does its best" to favor the production of programs that "guarantee behavior that increases fitness", but it can "fail" when the "right genes" are not available for selection.
In like manner the paleontologist George Simpson portrays "life substance" as exploiting its opportunities, solving problems, inventing novel and successful types of organization, "trying out" every conceivable possibility, "pulling through" various crises in its history, and ultimately transcending itself by producing an animal, man, capable of undergoing a totally new kind of evolution guided by "interthinking" rather than by interbreeding. And Edward O. Wilson, conceding that evolutionary naturalism, or "scientific materialism" as he calls it, is a form of mythology, a way of giving meaning, value, and direction to human activity, invites his readers to join him in unmasking rival mythologies (such as Christianity and Marxism), in strengthening the hold of the "evolutionary epic", and in plotting the future course of human evolution scientifically. Mary Midgley was right, then, in saying that the theory of evolution is "not just an inert piece of theoretical science" but also "a powerful folktale about human origins", a dramatic world picture capable of influencing human thought and action for good or ill.
One would like to feel optimistic about the scientistic mythology that has grown up around the theory of evolution, but it is hard to do so. The myth is intellectually dishonest, employing teleological and vitalistic figures of speech to describe processes that are advertised as "mechanistic" and pretending to derive from evolutionary biology values that stem from classical, Judaeo-Christian, and Enlightenment sources. It deifies science, denigrates philosophy and religion, and panders to Western culture's penchant for regarding science and technology as the guarantors of indefinite progress toward some hazy but glorious future paradise on earth. Worse yet, it fosters dreams of genetic manipulation and control designed to reshape imperfect human nature according to some scientistic ideal.
The difficulty, I think, lies not with evolutionary biology itself but with unsound ideas about science and its relations to nature and to the rest of human culture. As Mary Midgley has indicated, there is in Darwin's writings, cheek and jowl with his ambivalent ideas and feelings about competitive struggle in nature and society, a sense of wonder at the variety, beauty, and interconnectedness of living things, at nature's "endless forms most beautiful and most wonderful," and also a sense of reverence for life and of fellow-feeling and responsibility for all the inhabitants of our globe. Here, if anywhere, is the place to look for the religious and moral elements in the theory of evolution. Here, indeed, Sir Ronald Fisher found them in his lecture Creative Aspects of Natural Law (1950), delivered at Cambridge University as the fourth Eddington Memorial Lecture.
The creative causes of evolutionary change, said Sir Ronald, are to be found "in the actual life of living things; in their contacts and conflicts with their environments, with the outer world as it is to them; in their unconscious efforts to grow, or their more conscious efforts to move. Especially in the vital drama of the success or failure of each of their enterprises." Equally important, he added, is "the creative action of one species on another."
The timid antelope has played its part in the creation of the lion, and species long extinct must have left indelible memorials in their effects on species still surviving. Who knows if the mammals would ever have evolved, but for the creative activity of the dinosaurs?
As a Christian, Fisher drew an analogy between the theory of natural selection and the doctrine of salvation by works: "Both views emphasize responsibility for our actions, and for their natural consequences." Science, through its technological applications, has been largely responsible for mankind's growing impact on the global environment, Fisher acknowledged, but it has thereby made human beings increasingly sensitive to their responsibilities toward other living things.
We have come to expect kindness in the treatment of the domestic animals. We have come to deplore the irreplaceable loss of some of the species which ignorance and greed have exterminated, The future of some wild animals has occasioned sufficient anxiety for the provision of Parks and Nature reserves to be the normal policy of civilized peoples.
Science, it appears, does not dictate what moral and religious conclusions must be drawn from its effort to describe the interconnectedness of things in terms of general laws and processes. That interconnectedness and the human mind seeking to discover it are pre-scientific. The scientist is both a part of that interconnectedness and, at the same time, an observer and admirer of it. But if he is wise, he (or she, as the case may be) will feel reverence and a sense of obligation to the source of that interconnectedness, realizing that the scientific way of grasping it is but one of many ways and that the aim of human existence is neither pure intellection nor the command of nature for human purposes but the shared harmony of life with life and with the source of all life and being.
Copyright © 1999 John C. Greene
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