Three masters of philosophy who were not philosophers [Darwin, Newman, Freud] in Anthony Kenny's An Illustrated Brief History of Western Philosophy.. [Part 1]
CHAPTER 20
THREE MODERN MASTERS
CHARLES DARWIN
In his funeral oration on Karl Marx, Engels described the materialist conception of history as a scientific breakthrough comparable with Darwin’s discovery of evolution by natural selection. Unlike Marx’s theory, Darwin’s discovery was a genuine scientific advance, and the detailed discussion of it belongs to the history of science. But it casts a backward light on several philosophical issues we have encountered earlier, and philosophical as well as scientific conclusions have been drawn from it. Hence even an outline history of philosophy would be incomplete without a brief account of the theory and its philosophical implications.
Charles Darwin was born in Shrewsbury in 1809 and attended the school there before university studies in Edinburgh and Christ’s College, Cambridge. After taking his degree in 1831 he joined HMS Beagle on a five-year tour of the globe as resident naturalist; he published a record of his botanical and geological researches on the cruise in a series of works between 1839 and 1846. During the 1840s he began to develop the theory of natural selection which he eventually published in his great work The Origin of Species in 1859. This was followed by The Descent of Man in 1871 and a series of treatises on variations of structure and behaviour within and across species, which continued almost up to his death in 1882.
Before Darwin, biologists had worked out a classification of animals and plants into genera and species. All lions, for instance, belong to the lion species, which is a member of a genus of cats which includes also the tiger and the leopard. It is characteristic of a species that its members can breed with other members to produce offspring of the same species, and that unions between members of different species are commonly sterile.
The similarities between species which lead to their classification within a single genus may be explained in various ways. The most famous of those who drew up the classification into genus and species, the Swedish botanist Linnaeus, thought that each species had been separately created and the resemblances and difference between them reflected the design of the creator. An alternative explanation was that different species within a genus might be descended from a common ancestor. This idea long preceded Darwin: as we have seen, it was a speculation entertained by several philosophers in ancient Greece, and more recently it had been put forward by Darwin’s grandfather Erasmus Darwin, and by the French naturalist Lamarck. Darwin’s great innovation was to suggest the mechanism by which a new species might emerge.
Darwin observed, first, that organisms vary in the degree to which they are adapted to the environment in which they live, in particular with respect to their opportunities for obtaining food and escaping from predators. The long neck of a giraffe is an advantage in picking leaves from high trees; the long and slender legs of the wild horse help it to run fast in open plains and thus escape from its predators. Secondly, all plant and animal species are capable of breeding at a rate which would increase their populations from generation to generation. Even the elephant, the slowest breeder of all known animals, would in five hundred years produce from a single couple fifteen million offspring, if each elephant in each generation survived to breed. If an annual plant produced only two seeds a year, and their seedlings next year produced two and so on, then in twenty years there would be a million plants. The reason that species do not propagate in this way is of course that in each generation only a few specimens survive to breed. All are constantly engaged in a struggle for existence, against the climate and the elements, and against other species, striving to find food for themselves and to avoid becoming food for others.
Darwin’s insight was to combine these two observations.
Owing to this struggle for life, any variation, however slight, and from whatever cause proceeding, in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual and will generally be inherited by its offspring. The offspring, also, will thus have a better chance of surviving, for, of the many individuals of any species which are periodically born, but a small number can survive.
Human husbandmen have long selected for breeding those specimens of particular kinds of plant and animal which were best adapted for their purposes, and over the years they often succeed in improving the stock, whether of potatoes or racehorses. The mechanism by which advantageous variations are preserved and extended in nature was called by Darwin ‘natural selection’, in parallel with the artificial selection practised by stockbreeders. Unlike his predecessor Lamarck, Darwin did not believe that the variations in adaptation were acquired by parents in their own lifetime: the variations which they passed on were ones they had themselves inherited. The origin of these variations could well be just a matter of chance.
It is easy enough to see how natural selection can operate on characteristics within a single species. Suppose that there is a population of moths, some dark and some pale, living on silver birch trees, preyed upon by hungry birds. If the trees preserve their natural colour, pale moths are better camouflaged and have a better chance of survival. If, over the course of time, the trees become blackened with soot, it will be the dark moths who have the advantage and will survive in more than average numbers. From the outside, it will appear that the species is changing its colour over time.
Darwin believed that over a very long period of time natural selection could go further, and create whole new species of plants and animals. If this were the case, that would explain the difference between the species which now exist in the world, and the quite different species from earlier ages which, in his time, were beginning to be discovered in fossil form throughout the world. In explaining even the most complex organs and instincts, he claimed, there was no need to appeal to some means superior to, though analogous with, human reason. A sufficient explanation was to be found in the accumulation of innumerable slight variations, each good for the individual possessor.
In 1871 Darwin published The Descent of Man, in which he explicitly extended his theory to the origin of the human species. On the basis of the similarities between humans and anthropoid apes he argued that men and apes were cousins, descended from a common ancestor.
The case for Darwin’s theory was enormously strengthened in the twentieth century with the discovery of the mechanisms of heredity and the development of molecular genetics. It would not be to my purpose, and would be beyond my com petence, to evaluate the scientific evidence for Darwinism. But it is necessary to spend some time on the philosophical implications of his theory, assuming that it is well established.
From Darwin’s time until the present, evolutionary theory has met opposition from many Christians. At the meeting of the British Association in 1860 the evolutionist T. H. Huxley reported that the Bishop of Oxford inquired from him whether he claimed descent from an ape on his father’s or his mother’s side. Huxley – according to his own account – replied that he would rather have an ape for a grandfather than a man who misused his gifts to obstruct science by rhetoric.
Darwin’s theory obviously clashes with a literal acceptance of the Bible account of the creation of the world in seven days. Moreover, the length of time which would be necessary for evolution to take place would be immensely longer than the six thousand years which Christian fundamentalists believed to be the age of the universe. But a non-literal interpretation of Genesis had been adopted by theologians as orthodox as St Augustine, and few Christians in the twentieth century find great difficulty in accepting that the earth may have existed for billions of years. It is more difficult to reconcile an acceptance of Darwinism with belief in original sin. If the struggle for existence had been going on for aeons before humans evolved, it is impossible to accept that it was man’s first disobedience and the fruit of the forbidden tree which brought death into the world. But that is a problem for the theologian, not the philosopher, to solve.
On the other hand, it is wrong to suggest, as is often done, that Darwin disproved the existence of God. For all Darwin showed, the whole machinery of natural selection may have been part of a Creator’s design for the universe. After all, belief that we humans are God’s creatures has never been regarded as incompatible with our being the children of our parents; it is equally compatible with our being, on both sides, descended from the ancestors of the apes. Some theists maintain that we inherit only our bodies, and not our souls, from our parents. They can no doubt extend their thesis to Adam’s inheritance from his non human progenitor.
At most, Darwin disposed of one argument for the existence of God: namely, the argument that the adaptation of organisms to their environment shows the existence of a benevolent creator. But Darwin’s theory still leaves much to be explained. The origin of individual species from earlier species may be explained by the mechanisms of evolutionary pressure and selection. But these mechanisms cannot be used to explain the origin of species as such. For one of the starting points of explanation by natural selection is the existence of true-breeding populations, namely species. Modern Darwinians, of course, do offer us explanations of the origin of speciation, and of life itself; but these explanations, whatever their merits, are not explanations by natural selection.
In the case of the human species, there is a particular difficulty in explaining by natural selection the origin of language. [Dunbar coming up!] It is easy enough to understand how natural selection can favour a certain length of leg, because there is no difficulty in describing a single individual as long-legged, and we can see how length of legs may be advantageous to an individual. It does not seem plausible to suggest that in a parallel way the use of language might be favoured by natural selection, because it is not possible to describe an individual as a language-user at a stage before there was a community of language-users. For language is a rule-governed, communal activity, totally different from the signalling systems to be found in non-humans. Because of the social and conventional nature of language there is something very odd about the idea that language may have evolved because of the advantages possessed by language-users over non-language-users. It seems almost as absurd as the suggestion that banks evolved because those born with an innate cheque-writing ability had an advantage in the struggle for life over those born without it.
The most general philosophical issue raised by Darwinism concerns the nature of causality. The fourth of Aristotle’s four causes was the goal or end of a structure or activity. Explanations falling in this category were called teleological after the Greek word for end, telos.
Teleological explanations of activity, in Aristotle, have two features. First, they explain an activity by reference not to its starting point, but to its terminus. Secondly, they do their explaining by exhibiting arrival at the terminus as being in some way good for the agent whose activity is to be explained. Thus, Aristotle will explain downward motion of heavy bodies as a movement towards their natural place, the place where it is best for them to be. Similarly, teleological explanations of structures in an organism will explain the development of the structure in the individual organism by reference to its completed state, and exhibit the benefit conferred on the organism by the structure once completed: thus, ducks grow webbed feet so that they can swim.
Descartes was contemptuous of Aristotelian teleology; he maintained that the explanation of every movement and every physical activity must be mechanistic, that is to say it must be given in terms of initial conditions described without evaluation. Descartes offered no good argument for his contention; but in the subsequent history of science, blows were dealt at each of the two elements of Aristotelian teleology, by Newton and Darwin separately. Newtonian gravity, no less than Aristotelian natural motion, provides an explanation by reference to a terminus; gravity is a centripetal force, a force ‘by which bodies are drawn, or impelled, or in any way tend, towards a point as to a centre’. Where Newton’s explanation differs from Aristotle’s is that it involves no suggestion that it is in any way good for a body to arrive at the centre to which it tends. Darwinian explanations, like Aristotle’s, demand that the terminus of the process to be explained shall be beneficial to the relevant organism; but unlike Aristotle, Darwin explains the process not by the pull of the final state but by the initial conditions in which the process began. The red teeth and red claws involved in the struggle for existence were, of course, in pursuit of a good, namely the survival of the individual organism to which they belonged; but they were not in pursuit of the good which finally emerged from the process, namely the survival of the fittest species.
Not that Darwin’s discovery put an end to the search for final causes. Far from it: contemporary biologists are much keener to discern the function of structures and behaviours than their predecessors were in the period between Descartes and Darwin.
What has happened is that Darwin has made teleological explanation respectable, by offering a general recipe for translating it into mechanistic explanation. His successors thus feel able to make free use of such explanations, whether or not in the particular case they have any idea how to apply the recipe.
The major philosophical question which remains is this: is teleological explanation or mechanistic explanation the one which operates at a fundamental level of the universe? If God created the world, then mechanistic explanation is underpinned by teleological explanation; the fundamental explanation of the existence of anything at all is the purpose of the creator. If there is no God, but the universe is due to the operation of necessary laws upon blind chance, then it is the mechanistic level of explanation which is fundamental. But even in this case there remains the question whether everything in the universe is to be explained mechanistically, or whether there are cases of teleological causation irreducible to mechanism. If determinism is true, then the answer is in the negative; mechanism rules everywhere. It is not a matter of doubt that we possess free-will: but it is open for discussion whether or not free-will is compatible with determinism. If the human will is free in a way that escapes determinism, then even in a universe which is mechanistic at a fundamental level, there operates a form of irreducibly teleological causality. So far as I am aware, no one, whether scientist or philosopher, has produced a definitive answer to this set of questions.
[You have now reached the end of this Social Science Files exhibit.]
The Source of today’s exhibit has been:
Anthony Kenny, An Illustrated Brief History of Western Philosophy, 20th anniversary edition, John Wiley & Sons 2019
MGH: Anthony Kenny is a confirmed and reconfirmed agnostic, and greatly admires the work of Wittgenstein. (I am a confirmed and reconfirmed atheist, and a great admirer of Wittgenstein.) I was a little disappointed by Kenny’s treatment of Leibniz because I think he focused too much on Leibniz’s belief in God (there was so much of it that I had to edit a lot of ‘God’ discussion out of our earlier exhibit of Kenny on Leibniz). It seems to me that Leibniz was lighthearted and at times a little self-mocking about his belief in God (he gave it an amusing binary evolutionary notation — how you get 1 out of zero), and he certainly never let this belief get in the way of his hard-nosed theorising about methods of science and his science of jurisprudence.
But the more I read Anthony Kenny the more I admire the fair-minded way he systematically and cleverly confronts the ‘God’ questions—which, after all, are and have been inescapably everywhere to be found during the evolutions of human society—with philosophical logic and rational interrogation. This skill is in evidence in this chapter juxtaposing Three Masters (who were not ‘philosophers’), which is one the reasons I am displaying it.
I will, however, have soon to quote Robin Dunbar on the origins of language, which I think demonstrates that human transition to language was much more Darwinian than Kenny is willing to admit. On the other hand, biology and its companion disciplines are incredibly fast-moving sciences, and Kenny’s book is more than 20 years old. Twenty years is a very long time in modern science but infinitesimal in philosophy.
Next is John Henry Newman. I also want later to exhibit Kenny’s chapter on Wittgenstein’s Philosophical Investigations. As a prelude to tomorrow’s John Henry Newman exhibit I include below a comment Kenny makes about Wittgenstein vis-à-vis Newman:
In discussing the propositions which make up our world-picture, Wittgenstein recognized that he was addressing the same problems as were posed by Newman in the Grammar of Assent: how is it possible to have unshakeable certainty which is not based on evidence? But he disapproved of the purpose for which Newman undertook his investigations, namely to prove the reasonableness of Christianity. Wittgenstein thought that Christians were obviously not reasonable; they based enormous convictions on flimsy evidence. But this did not mean that they were unreasonable; it meant that they should not treat faith as a matter of reasonability at all.
Social Science Files displays multidisciplinary writings on a great variety of topics relating to evolutions of social order from the earliest humans to the present day and future machine age.
‘The Heller Files’, quality tools for Social Science.