Darwin's Metaphor:
Nature's Place in Victorian Cultureby
Robert M. Young
[ Introduction | Preface | Chapter: 1 | 2 | 3 | 4 | 5 | 6 | Notes | Bibliography | Index ]
CHAPTER III
THE ROLE OF PSYCHOLOGY IN THE NINETEENTH-CENTURY
EVOLUTIONARY DEBATE
I
The history of psychology is a discipline whose relations with psychology and with the history of science have yet to be defined. This essay is a case study in the relations between the history of psychology and the nineteenth-century debate on evolutionary theory, a debate that reveals an intimate union of psychological, biological, social, and ideological issues. The argument of the essay complements the study of Malthus' role given in Chapter 2 and asks broader questions about the role of what we now call ',the "human sciences" in the evolutionary debate then and now. My aims, as always, are also historiographic and political.
I am preoccupied with the history of attempts to apply the methods and assumptions of science to the study of people. I hasten to add that I do history because I believe that our present predicament might be eased if we could gain greater perspective on the assumptions we make and on the ways in which the heritage of the past constrains our present thinking. The structure and the conceptual affinities of past controversies can perhaps help us to take a broader view of our own situation. Historical studies thereby become an analytic tool, not an antiquarian quest in search of who did what first or whether or not A is buried in B's grave.
The writing of the history of a subject at any point in time is highly constrained by contemporary conceptions of the subject itself. This is particularly true of the history of psychology, because its small number of practitioners is on the defensive. They feel themselves to be under attack from colleagues who wonder
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why they aren't doing experiments, and they also feel shunned by professional historians of science who do not see the relevance of the history of psychology to the mainstream of the history of science. If I were writing this whole essay on the historiography of psychology, I would try to point out in some detail the fundamental philosophical issues behind these reactions. Instead, I shall only say that they reflect the methodological and metaphysical insecurity of all three groups - the historians of psychology and of science, and the practicing experimentalists. It is therefore not surprising that the history of psychology is in a very primitive state and that its practitioners have, until very recently, tended to write synoptic surveys - The History of Psychology from Plato to NATO - to show that they have culture, or they search (I think vainly and irrelevantly) for the first truly scientific treatment of this or that problem.
II
I should now like to address myself to the issues I have raised by directing attention to the evolutionary debate in the late eighteenth and nineteenth centuries. In doing this I hope to provide some evidence for the claim that there are intimate relations between psychological, social, philosophical, and theological issues, and thereby to show the importance of wider issues for the history of psychology. More importantly, I shall try to show the crucial role of the history of psychology in the mainstream of the history of science, considered in its social and political contexts.
At first glance this seems to be an easy task. It is a commonplace that the furor over evolution was largely due to the wider implications of the theory, i.e., that the theory of organic evolution implied that man was descended from the apes. Put slightly more formally, it meant that the origin of man occurred by means of the continuous operation of natural laws and not by special creation. This, in turn, implied that it was no longer possible to separate mind and culture from the domain of scientific laws. Humanity and all its works - body and mind, society and culture became, in principle, part of the science of biology. The continuity of types was based on the continuity of natural causes, and discontinuities between body and mind and between nature and culture became untenable. God did not act by isolated
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interpositions, and moral responsibility no longer had a separate, divinely ordained basis in the freedom of the will.
Notice, however, that I have not yet suggested that discoveries in psychology were central to this set of issues. On the contrary, it is usually argued that it was the theory of evolution which gave psychology - especially comparative, developmental, and physiological psychology - a sound conceptual basis. Charles Darwin's theory was not derived from such findings. Rather, it was derived primarily from studies in geology, paleontology, zoogeography, theory of classification, the study of domesticated animals, and the practices of breeders. Once established, the theory transformed psychology. It is true that Darwin indulged in some speculations about psychology and mental inheritance as he was working out his evolutionary theory, that he made numerous notes on instinct, and that he wrote a short study in child development as well as two books that dealt with issues recognizably psychological: The Descent of Man and The Expression of the Emotions in Man and Animals. However, it is clear that these were not his central concerns. He considered The Descent of Man to be an unoriginal work, and he handed his notes on instincts and comparative psychology to George J. Romanes, who set out to do for the evolution of the mind what Darwin had done for the evolution of the body.
If we look closely at The Descent of Man, we find Darwin accepting the principles which follow from evolutionary continuity. However, his examples are excessively anecdotal, and his categories of analysis are drawn from a pre-evolutionary psychological tradition. Here is a sample of his approach to the issues:
It is, therefore, highly probable that with mankind the intellectual faculties have been mainly and gradually perfected through natural selection; and this conclusion is sufficient for our purpose. Undoubtedly it would be interesting to trace the development of each separate faculty from the state in which it exists in the lower animals to that which exists in man; but neither my ability nor knowledge permits the attempt.
Darwin had taken the same, rather laconic, approach to the problem of instincts in On the Origin of Species. This is slightly surprising, since he had been very aware of the importance of the problem of mind from the beginning of his researches. The following passages appear in his notebooks of 1837 and 1838, the period in which he was developing his conception of natural selection,
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but before he had the insight which will be discussed below: "My theory would give zest to recent and fossil comparative anatomy; it would lead to the study of instincts, heredity, mindheredity, whole [of] metaphysics." In the same period he was also concerned with the origins and philosophical status of mind, and wrote: "Why is thought being a secretion of brain more wonderful than gravity a property of matter?"
However, as I have said, he gave his notes on instinct and mind to G. J. Romanes, who some believe to be the most important pioneer in comparative psychology. When Romanes asked Darwin's advice about the question of the origins of mind, Darwin was again rather casual, and his reply did not reveal the intensity of interest and the penetrating reasoning which characterized, say, his correspondence about plants:
I have been accustomed to looking at the coming of the sense of pleasure and pain as one of the most important steps in the development of mind, and I should think it ought to be prominent in your table. The sort of progress which I have imagined is that a stimulus produced some effect at the point affected, and that the effect radiated at first in all directions, and then that certain definite advantageous lines of transmission were acquired, inducing definite reaction in certain lines. Such transmission afterwards became associated in some unknown way with pleasure or pain. These sensations led at first to all sorts of violent actions, such as the wriggling of a worm, which was of some use. All the organs of sense would be at the same time excited. Afterwards definite lines of action would be found to be the most useful, and so would be practiced. But it is no use my giving you my crude notions.
Darwin was, therefore, very diffident about psychology and characteristically deferred to Spencer, Romanes, and Huxley on psychological topics. Historians of psychology have, nevertheless, habitually attributed a great deal to Darwin's influence on the subject. My point is that, whatever the implications of his work for psychology and whatever the long-term influence of evolutionism on psychology, it is clear that the main sources of Darwin's theory were derived from the studies of a field naturalist and from geology. This was where his real interests lay and where he made his own contributions to the findings, as opposed to the theories and assumptions, of science. He wrote twenty books, four of which were major (Origin, Variation of Plants and Animals, Descent of Man, Expression of the Emotions), of which only the last was primarily
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psychological. And even that was really only intended as an essay to be appended to The Descent of Man and was published separately because of the excessive length of the Descent. By comparison, eight of his books were strictly about plants.
Having denigrated the significance of psychology in Darwin's work, I want to make one important but unobvious exception: the influence of Malthus' Essay on Population on Darwin's ideas. This, as we have seen, was a crucial influence, but in order to understand it as part of the history of psychology, I must make a large detour that will introduce my main theme, i.e., the extremely intricate ways in which psychological ideas influenced the evolutionary debate, both implicitly and explicitly, in its details as well as in its very wide implications. I want to address myself to this issue in two ways. The first is to stress the relative isolation of the internalist history of psychology in the nineteenth century from the mainstream of the great debate on man's place in nature, and the second is to go back and look again to see that at another level psychological theories were at the very heart of the debate, providing its most fundamental conceptions and touching on its widest implications for human nature and society and indeed for the philosophy of nature itself.
III
First, let us consider the isolation of the evolutionary debate from the internal history of psychology. If we recall what I said about the significance of the evolutionary debate for views of human nature, one would expect that the findings of psychologists would provide the data for a central area of contention. What is the evidence for mental determinism? How closely comparable are the behaviors of men and lower organisms? Is there a perfect correlation between the mind's activities and the physiology of the nervous system? What are the grounds for believing that criminals and lunatics have no control over their actions? All of these issues were being assiduously investigated and debated in the late eighteenth century and throughout the nineteenth. Surely these debates should be closely integrated with the evolutionary debate?
One might object that the general public was not expert enough consider the detailed findings of psychologists, physiologists, and psychiatrists. This is an initially plausible hypothesis until we
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look at the astonishing level of sophistication of the public debate in the nineteenth-century periodicals on such abstruse issues as the details of geological stratification and natural history. The most prestigious of the periodicals were the three main quarterlies, and from the beginning the Edinburgh Review (1802), the Quarterly Review (1809), and the Westminster Review (1824) contained extended critical essays on nearly every significant work in geology and biology, written by the leading scientists, philosophers, and theologians of the period. Works on the philosophy of science and on natural theology received the same exhaustive treatment. The complex interrelations among geological, biological, and theological issues were also discussed at great length.
In the same period three main sorts of investigations were occurring in psychology. The first concerned the laws of mind and centered on the concept of the association of ideas. The tradition of associationist psychology goes back to the work of David Hartley (1749) (to which I shall revert in the next section) and can be traced ultimately to the mainstream of the Scientific Revolution in the works of Newton and Locke. The association of ideas was also a basic assumption of the epistemology and psychology of David Hume and had continental parallels in the work and influence of Condillac. In the nineteenth century there were extremely important writings in this tradition by Thomas Brown, James Mill, J. S. Mill, Alexander Bain, Herbert Spencer, and G. H. Lewes. The laws of mind, and their relations with the laws of nature, with society, and with education, were discussed at great length. These books were reviewed in the periodicals, but there is very little sustained treatment of them in connection with the evolutionary debate until well after 1860. Also, the context in which they were considered was neither primarily psychological nor biological.
Similarly, beginning as early as 1811, there were important experiments on the structure and function of the central nervous system. By the early 1820s, the functional division of the spinal nerve roots was being investigated experimentally in Britain, France, and Germany. In the same period there were extensive experiments on the functions of the brain which might have given strong support to the antideterminists and antimaterialists in the evolutionary debate. Between 1822 and 1870 numerous experimental tests provided no evidence for localization of functions in the brain or for the production of purposive movements by
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artificial stimulation of the cerebral cortex. Yet the interpretation placed on these experiments was that they supported the autonomy of an indivisible mental substance and belief in free will. There were extensive debates on these findings in the physiological and clinical journals, but the issues found almost no expression in the general debate. This is all the more curious, since the evolutionary debate focussed on the structure of the brain after 1860, and the people conducting the public debate about evolution were also intimately involved in the physiological and medical debates. I am thinking particularly of Richard Owen and T. H. Huxley.
There were also heated controversies on the reflex concept and on how far up the neuraxis automatic, reflex functions prevailed. Eminent physiologists differed on issues that were perfectly parallel to those in the mainstream of the general evolutionary debate. Thus, while evolutionists argued about whether or not the activities of animals and men were entirely determined by unchanging laws, the physiologists differed on whether or not the thinking part of the brain - the cerebral cortex - obeyed the same laws as the automatic, reflex functions of lower brain centers and the spinal cord. Once again, it was often the same people who took leading parts in both debates. William Carpenter and G. H. Lewes are notable examples.
Even when, in the 1840s, Thomas Laycock applied the reflex concept to all levels of the central nervous system and argued for complete continuity of function, he did not do so on the basis of the theory of evolution but, on the contrary, based his claims on the principle of continuity in the antievolutionary theory of the Great Chain of Being. He did this in spite of the fact that the general version of his theory was presented to the British Association in 1844, the year of publication of a widely read and hotly debated argument in favor of evolution, Vestiges of the Natural History of Creation.
Twenty-five years later, when the tide had turned, and it was demonstrated by experiment that movements which had hitherto been attributed to free will could be produced by localized electrical stimulation of the cerebral cortex, these findings might have been taken up by the evolutionists and determinists. They might have told the general public that thought and action were entirely functions of brain centers and that free will was thereby proven to be a chimera. But they didn't. This work was based on inferences
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drawn from experiments on dogs and monkeys, whose relevance for man was based on evolutionary theory, but the implications of the findings for man were not driven home in the general debate.
An indication of this isolation can be found in Darwin's Descent of Man. There was a section on the brain added to the second edition, which Darwin persuaded Huxley to write. Even so, the two editions of that work - 1871 and 1874 - appeared in the period of greatest discovery in the physiology of the cortex, and no whisper of these developments occurs in the book: the argument is conducted entirely in terms of comparative anatomy, without reference to physiology. The issue of comparative anatomical structures in the brain had preoccupied Huxley in the 1860s, in his debates with Owen on the brain. It could, of course, be argued that Huxley was not au fait with developments in cerebral physiology. If so, he must have learned it fairly soon thereafter, since the Royal Society turned to him to act as referee for some very delicate issues raised by papers which David Ferrier submitted on the subject in the mid-1870s. Yet neither his contribution to Darwin's book nor his popular essays draw on the findings and theories of psychologists and neurophysiologists. The same can be said of William Carpenter, who was the chief expositor of experimental physiology in Britain at the same time that he was one of the most active and respected interpreters of evolutionary theory.
Having discussed the curious sequestration of associationism and neurophysiology - two approaches with evolutionary and determinist implications - I want to increase our bewilderment by briefly discussing the example of phrenology. In this case our problem is made worse by the fact that phrenology was one of the most popular and publicly controverted theories in the nineteenth century. Its alleged determinist, materialist, and atheist implications were grasped at the outset, and its adherents were regularly reviled in the main periodicals - for example, in the third number of the Edinburgh Review, again in 1815, and again and again. I know of only one extensive, balanced treatment of it - by Richard Chevenix in the Foreign Quarterly Review in 1828. The same people who attacked uniformitarian geology and evolutionism sallied forth against the putative atheism and degradation of man which lay in the phrenological doctrines of Gall, Spurzheim, and their Scottish exponent and popularizer, George Combe. Phrenological works were in the library of every Mechanics' Institute, and by
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1832 there were twenty-nine phrenological societies and numerous publications in Britain (with others in France and even more in America). Remember that Combe's Consitution of Man sold 50,000 copies between 1835 and 1838, 80,000 by 1847, and a total of over 100,000 by 1865. It is said that the homes which contained only the Bible and Pilgrim's Progress chose Combe's Constitution of Man as their third book. I shall argue below that phrenology played a central role in the development of evolutionary theories, but the close conceptual affinities between phrenology and the issues in the evolutionary debate were not a significant feature of the public debate. The condemnation of phrenology and that of uniformitarian geology and evolutionism went on side by side.
To complete our confusion, I should point out that these three themes in the history of psychology - associationism, neurophysiology, and phrenology - came together in the writings of Alexander Bain and that they were placed in the context of evolutionism by Herbert Spencer. In the crucial period of 1855-1859, when they were providing perfect ammunition for the wider debate, the connection was not widely grasped. When psychophysiology was placed on an experimental basis in the early 1870s by the findings of Fritsch and Hitzig and of Ferrier in their research on cerebral localization, these findings were available for the debate surrounding The Descent of Man, but they were not taken up. When they were extended by physiologists and neurologists - especially John Hughlings Jackson - the failure of the evolutionists and anti-evolutionists to exploit them becomes astonishing.
IV
Having borne with me this far, you will have anticipated that I have been setting up an elaborate rhetorical question which I shall now proceed to answer. If so, you will be half-disappointed, and the half that I cannot explain is the most puzzling one. That is, it is easy to point out that the anti-evolutionaists understandably did not want to conduct the debate on grounds which their whole position required them to deny in principle as long as they could hope to defeat the enermy on safer territory. For example, it was preferable to defeat the uniformitarians on the battlefield of the history of the earth. If this could be shown to be unexplainable without recourse to divine intervention, then the question of the
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vulnerability of man's special place in nature need never arise. Even Lyell's uniformitarian geology represented an outwork, protecting the central citadel of man's special nature. He was uniformitarian about the history of the earth, but denied biological and human evolution.
This is not to say that psychological, physiological, and phrenological issues never got mentioned in the general debate. However, when they did come up, they were isolated from the mainstream of the debate and/or treated polemically. Those who were upholding the traditional picture of the order of nature and society were unwilling to dignify the sciences of mind and brain by debating their findings, when their whole position required them to deny that man's mind lay within the domain of science. This interpretation is given support by the appearance of Mind, the first professional journal in psychology and philosophy in any country. By the time it was founded - very tardily, we would say - in 1876, psychologists were fed up with being fobbed off. The journal was financed by Bain, and the first editor was his protégé, George Croom Robertson. In the prefatory remarks in the first issue, Robertson wrote:
Even now the notion of a journal being founded to be taken up wholly with metaphysical subjects, as they are called, will little commend itself to those who are in the habit of declaring with great confidence that there can be no science in such matters, or to those who would only play with them now and again....... MIND intends to procure a decision on this question as to the scientific standing of psychology.
This partially satisfactory explanation of why the defenders of man's special status were unwilling to debate the laws of mind and brain - because they denied the relevance of scientific methods and laws to higher functions - leaves us with the problem of why the proponents of evolutionism and of a science of man did not draw on the detailed findings of psychologists and neurophysiologists to bolster their own case. Since I simply don't know the answer to this at the straightforward level, I will withhold my paltry speculations on the subject and turn to the much more significant role which psychological theories played at a deeper level in the theories of the evolutionists.
Before doing so, however, I should add that psychology was in some respects in good company. While I cannot explain its
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isolation to my own satisfaction, I can point out that the relevance of findings in one discipline to those in another can take time to dawn on very clever people - even the people whom we see as most directly concerned with the integration of those sets of findings. In the nineteenth-century debate on man's place in nature there were relatively few articles which, as they say nowadays, got it together. I have found only one essay in the pre-1859 period which closely integrates the question of evolution with the question of the natural history of man, and that was written by a medical psychologist, Henry Holland, in the Quarterly Review in 1850. For the most part, however, the debate on man's place in nature was not an integrated debate. It was, rather, a network, involving partial overlaps between issues that seem obviously to be related from the anachronistic vantage point of a current observer. There was uniformitarian geology, but its chief preoccupation was to combat catastrophism. Its use of paleontology was in that context. Viewing paleontology from another perspective, it was closely integrated with the study of comparative anatomy under the inspiration of Cuvier. Richard Owen was called "the English Cuvier," but it was not until the 1860s that debate centered on comparative anatomy as applied to man, a debate in which the advocate of evolution, Huxley, engaged the opponent, Owen. The quarrel was refereed by Lyell, who was still six years away from accepting evolution. Physical anthropology was related to the problem of the antiquity of man, while its preoccupation with skulls was strongly influenced by issues that had been raised by phrenology. But anthropology in general was concerned with issues which it had inherited from speculative history and Utilitarianism. The foundation of an Anthropological Society in 1863 was not a consequence of evolutionism but a reflection of earlier preoccupations. When anthropologists drew ideas from evolutionism, it was not a new inspiration, but an alliance which served to obscure other, deeper problems in their work. The study of the geological evidences of the antiquity of man was done for a variety of reasons, but the concentration on the issue in the 1860s was not in any simple sense seen as a consequence of Darwin's theory. Finally, students of social development, like those in anthropology, had preoccupations which owed more to questions that had faced the Scottish Enlightenment and the Utilitarians, rather than to evolutionism. My point in parading these disciplines is to apply to the
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past a truism of current intellectual life. Whatever an outsider may consider to be the relevant conceptual affinities and common interests, ditterent disciplines have their own preoccupations, and the relations between these form a loose network of issues and interests, which does not conform to any abstract pattern. Professionals, students, and lay people differed as much then as they do now about the relevance of given issues. It could be argued that our ability to see this clearly in examples drawn from the past might help us to loosen our categories and perhaps recover some of our lost curiosity.
The example of the geological evidence of the antiquity of man is revealing. What could be more central to the question of man's place in nature? Many alleged fossil human remains had been found in the eighteenth century and again in the 1820s by William Buckland, the main exponent in that period of the recent and special origin of man. These were found in strata which also contained the remains of extinct animals, but they were all explained away, and Buckland wrote confidently in 1836 that there was no convincing evidence of fossil human remains which were laid down with the bones of extinct animals. Charles Lyell - Buckland's geological opponent but a believer in the special creation of man - saw some very convincing evidence in 1833 and wrote that the circumstances of the remains were "far more difficult to get over than I have previously heard of." As late as the 1855 edition of his Principles of Geology, he remained unconvinced. However, as early as 1849, and again in 1857, Boucher de Perthes had reported unequivocal evidence of fossil humans with extinct animals, but nobody was convinced, and I have seen no report of these findings in the general debate at the time. Even Darwin was forced to admit in 1863, "I am ashamed to think that I concluded the whole was rubbish."
However, in 1858, in Brixham Cave in South Devon near Torquay, some flint implements were found in direct association with bones of extinct animals from the Pleistocene. This was reported to the British Association in 1858, but there is no reference to these findings in Darwin's Life and Letters. There was another paper read to the Royal Society in May 1859, after thejoint DarwinWallace paper to the Linnean Society in July 1858, in which they announced their theory of evolution by natural selection. This paper was concerned with additional findings in the Somme Valley.
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The debate was largely confined, however, to geologists and antiquaries. Lyell went to France to see for himself and confirmed the findings in his Presidential Address to the British Association in 1859. Once again, however, these startling confirmations of the worst fears of the anti-evolutionists did not appear in the reviews of Darwin's Origin of Species in 1860. Indeed, they were hardly mentioned at all in the public debate, until Lyell forcibly drew attention to them in 1863 in The Geological Evidences of the Antiquity of Man; and even he remained - as Darwin saw it - maddeningly uncommitted to their implications in support of evolution. By 1871, the connection between the question of man's antiquity and acceptance of evolution was much clearer, and Darwin could allude to them rather complacently in the introduction to The Descent of Man: "The high antiquity of man has recently been demonstrated by the labours of a host of eminent men, beginning with M. Boucher de Perthes; and this is the indispensable basis for understanding his origin. I shall, therefore, take this conclusion for granted, and may refer my readers to the admirable treatises of Sir Charles Lyell, Sir John Lubbock, and others." My point in giving this example is that, as with the study of psychology, neurophysiology, and phrenology, we can understand the failure of opponents of evolution to give publicity to such findings, but the tardy integration by the proponents of evolution is odd. In any given period, intellectual life is fragmented in ways that appear bizarre to those who have the benefit of hindsight.
V
I appreciate that the structure of this essay is maddeningly parenthetical and even recursive. I now want finally to make my positive case. I want to begin with another truism, one that is often forgotten by those who view the past through spectacles crafted in the workshops of current disciplinary boundaries: the river of nineteenth-century naturalism was fed by many streams. The part of that river which interests us most is that which led to the interpretation of man in naturalistic terms. I have mentioned that evolutionary theory drew on geological, paleontological, natural historical, and breeders' interests and issues. But it also drew on Utilitarianism, associationism, phrenology, mesmerism, Owenite socialism, Positivism, and scientific historical criticism of the
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Bible. For present purposes I want to draw attention to the number of streams in that second list which are psychological. Indeed, we could extend it to include classical economics and the development of sociological and anthropological theory. I want to point out the specific role of psychology in evolutionary and social theories, but in order to do so we must look below the surface. Before Bain, psychology was not seen as a discipline in its own right. It was playing a broader social and intellectual role, and in the development of evolutionary theory its influence was more abstract. Thus, for example, important psychological works were seen in social, theological, ethical, educational, colonialist, and logical contexts. This is particularly true of associationist psychology in the writings of the Utilitarians or Philosophical Radicals. Similarly, phrenology was propagated and well received as a platform for social, educational, and public health reforms. It was offered as the key to all philosophical and social problems - a panacea for all social ills. If we are to understand the role of psychology in the evolutionary debate, we must stop looking for it at the level which has been reviewed thus far in the argument. My point for the remainder of this essay is that psychological theories lay at the very basis of much of evolutionary theory. Indeed, it can be argued that in many respects evolutionary theory (as well as theories of progress, Utilitarianism, and social science) was applied psychology.
In order to see this, however, we must look again at certain key figures, not all of whom are usually regarded as psychologists. It is generally acknowledged that Descartes and Locke were figures in whose work there were important and intertwined strands of ontology, epistemology, physical science, theology, psychology, and (implicitly in Locke, explicitly in Descartes) physiology. But the effective beginning of the modern tradition in empiricist psychology is usually attributed to David Hartley's Observations on Man, His Frame, His Duty and His Expectations, which appeared in 1749. Hume's work also contained very influential arguments about the association of ideas, and although he spelled out in detail some of the laws of association, he eschewed any speculation on the physical basis of the associative process. The association of ideas had been an afterthought in Locke's Essay, and although it was central to Hume's argument, it is still the case that he was preoccupied with epistemological and ethical issues. The same
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argument can be made about Hartley's Observations, since he was really most concerned with questions of natural theology, morality, and the afterlife. Nevertheless, in integrating arguments drawn from Locke, John Gay, and Newton, he went into great detail about the associative process in the primarily psychological context of learning and constantly related this to a theoretical framework based on vibrations in the brain. For present purposes, it was Hartley's formulation which was most influential in providing a mechanism for changing utilities and adaptations. His detailed theory allowed others to speculate on ordered change through experience in both the psychological and, by analogy, the somatic structural realms. His ideas were the fountainhead for the development of the associationist tradition in psychology, but they were also used in theories of progress and evolution. Thus, for example, Erasmus Darwin introduced the section on "Generation," in which he puts forth his theory of evolution in Zoonomia with the following passage:
The ingenious Dr. Hartley in his work on man, and some other philosophers, have been of the opinion, that our immortal part acquires during this life certain habits of action or of sentiment, which become for ever indissoluble, continuing after death in a future state of existence; and add, that if these habits are of the malevolent kind, they must render the possessor miserable even in heaven. I would apply this ingenious idea to the generation or production of the embryon, or new animal, which partakes so much of the form and propensities of the parent.
Owing to the imperfection of language, the offspring is termed a new animal, but is in truth a branch or elongation of the parent; since a part of the embryon-animal is, or was, a part of the parent; and therefore in strict language it cannot be said to be entirely new at the time of its production; and therefore it may retain some of the habits of the parent-system.
At the earliest period of its existence the embryon, as secreted from the blood of the male, would seem to consist of a living filament with certain capabilities of irritation, sensation, volition, and association; and also with some acquired habits or propensities peculiar to the parent: the former of these are in common with other animals; the latter seem to distinguish or produce the kind of animal, whether man or quadruped, with the familiarity of feature or form of the parent.
Erasmus Darwin has here adapted Hartley's argument and employed it as the basis for a theory of evolution. First, he has taken
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principles which Hartley had used to refer to the afterlife; -he has secularized them and treated inheritance as an extended form of learning. In so doing, he treats the offspring, its inherited habits, and its bodily features as a prolongation of the acquired experiences of the parent. Associationist psychology, suitably extrapolated, becomes evolution. The other examples I shall cite are similar in using psychological theories as the basis for other sorts of theories, although there is space only to mention them.
Joseph Priestley also drew on Hartley's psychological theories in support of his necessitarianism and abrogated Hartley's vestigial mind-body dualism in support of his Unitarian materialist progressive philosophy of nature. This served as the foundation for his work in such diverse fields as theology, chemistry, and politics. In the sphere of social theory, William Godwin, one of the founders of modern anarchism, based his theory of inevitable and indefinite human progress on Hartleyan psychological mechanisms. The writings of James and J. S. Mill, and the logical, educational, social, and political theories which they espoused, were also based on associationist principles.
Looking across the Channel, the epistemological and psychological writings of Condillac also employed a sensationalist epistemology and an associationist mechanism. These were taken up by Condorcet as the basis for his theory of human progress in the Sketch for a Historical Picture of the Progress ofthe Human Mind (1795) in a way that parallels Godwin's use of associationism in England. Paralleling Erasmus Darwin's evolutionism, one finds one aspect of Lamarck's evolutionary theory also dependent on the inheritance of characteristics that were acquired through the repeated strivings of individuals. This aspect was secondary in his theory to an inherent tendency to progress, but, as we shall see, some of his interpreters made it the primary factor.
I have provided these examples of the influence of the psychological writings in the period before the nineteenth-century debate to show their fecundity in generating biological and social theories. It is an important task - one to which historians of psychology and of the other sciences have not begun to address themselves - to consider how many fundamental aspects of the so-called Scientific Revolution can be reinterpreted from the point of view of psychological theories. After all, the fundamental ontological, epistemological, and methodological shifts during the
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sixteenth and seventeenth centuries were, in large measure, concerned with problems of perception, purposiveness, and objectivity - topics that are central concerns of current psychology.
But our main concern is with the nineteenth-century debate, and I want to address myself to the writings of the three main evolutionary theorists in Britain: Darwin, Wallace, and Spencer. In the crucial period in which he was formulating his theory, Charles Darwin tells us that he needed a basis for making an analogy from the artificial selection of breeders to a natural process whose directionality did not depend on the intentions of a conscious selecting agent. How, to put it crudely, could nature select? In providing an answer to this, Darwin drew on a theory which was rooted in associationist psychology but which was at two removes from the basic Hartleyan doctrine. As a social doctrine, Utilitarianism depended on the associationist pleasure-pain theory of learning. In its economic form it required that men act in their rational self-interest, seeking the pleasures that flow from employment and avoiding the pains of poverty. The equilibrium and wealth of society depended on this mechanism. Pleasure and pain became the rewards and punishments of rational social and economic behavior. The system worked if there was enough to go around or if enough wealth could be created - if nature was bountiful enough and man industrious enough. Adam Smith tended to feel that they were. Twenty years later, T. R. Malthus took the opposite view, putting a different face on social equilibrium and pointing out the checks on progress which, you will recall, were being advocated on the basis of parallel extrapolations from sensationalism and associationism by Godwin and Condorcet. Malthus pointed out that nature was not bountiful enough, human industry was not inventive enough, and the sexual appetite was too strong. The conflict between the limits of nature and industry, on the one hand, and population growth, on the other, produced laws of struggle. He interpreted struggle as a benevolently designed cosmic learning theory:
I should be inclined ... to consider the world and this life as the mighty process of God, not for the trial, but for the creation and formation of mind, a process necessary to awaken inert, chaotic matter into spirit, to sublimate the dust of the earth into soul, to elicit an ethereal spark from the clod of clay. And in this view of the subject the various impressions and excitements which man receives through life may be considered as the forming hand of his Creator, acting by general laws, and awakening
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his sluggish existence, by the animated touches of the Divinity, into a capacity of superior enjoyment. The original sin of man is the torpor and corruption of the chaotic matter in which he may be said to be born.
He continues:
The first great awakeners of the mind seem to be the wants of the body. They are the first stimulants that rouse the brain of infant man into sentient activity, and such seems to be the sluggishness of original matter that unless by a peculiar course of excitements other wants, equally powerful, are generated, these stimulants seem, even afterwards, to be necessary to continue that activity which was first awakened. . . . From all that experience has taught us concerning the structure of the human mind, if those stimulants to exertion, which arise from the wants of the body, were removed from the mass of mankind, we have much more reason to think that they would be sunk to the level of brutes, from a deficiency of excitements, than that they would be raised to the rank of philosophers by the possession of leisure....... Necessity has been with great truth called the mother of invention.......
To furnish the most unremitting excitements of this kind, and to urge man to further the gracious designs of Providence, by the full cultivation of the earth, it has been ordained that population should increase much faster than food. . . . Strong and constantly operative as this stimulus is on man to urge him to the cultivation of the earth, if we still see that cultivation proceeds very slowly, we may fairly conclude that a less stimulus would have been insufficient. . . . Had population and food increased in the same ratio, it is probable that man might never have emerged from the savage state.
The mechanism had produced progress, but the means were painful. The only hope of mitigating the resulting suffering was "moral restraint" from premature marriage, and we have seen that Malthus did not put much faith in this partial palliative. I have quoted the rationale for his mechanism at length in order to offer convincing evidence that his explanations of progress and the restraints on it were generalizations of the pleasure-pain theory of learning: it caused progress, just as the survival or death of individuals constituted the ultimate sanctions of the law of population. As I said above, Darwin read Malthus' Essay on Population (in the sixth edition, where the arguments I have quoted are not offered in a summary form) at the crucial time when he tells us he was looking for a basis for an analogy between artificial and natural selection. Both his working notebooks and his retrospective accounts make it clear that the Malthusian population theory,
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when applied to plants and animals (and, secondarily, to man), provided the concepts of law and of natural pressure which Darwin required in order to formulate the theory of evolution by natural selection.
The case of A. R. Wallace, the co-discoverer of the theory of evolution by natural selection, was different in important respects. I only want to make a few observations about it. He did not reach the theory by analogy to artificial selection. Indeed, he denied the analogy. However, as was shown in Chapter 2, Malthus' conception of struggle also provided him with the key to the theory of natural selection. In the cases of both Darwin and Wallace, the concepts of species survival and extinction were explicit generalizations of the Malthusian concepts of population survival and death, and these were based on utilitarian concepts which, in turn, were derived from the association psychology. It is ironic that Wallace later claimed that the principle of utility was a corollary of the concept of natural selection: "The utilitarian hypothesis . . . is the theory of natural selection applied to the mind. . . ." I should perhaps add that in addition to the influence of Malthus and Lyell on him, Wallace's naturalistic approach to man was derived from three main sources: Robert Owen's socialism, Robert Chambers' Vestiges of Creation, and George Combe's Constitution of Man. All three of these drew on the principles of phrenology to support their biological approach to human nature.
If we turn to the writings of the third main evolutionist, Herbert Spencer, we find a complicated situation which begins, for our purposes, with his first book, Social Statics (1851). His central purpose in that book was to rebut moral and social theories based on Utilitarianism, theories which, of course, depend on associationism. Spencer considered the psychology of the Utilitarians to be too abstract, thereby paying insufficient attention to individual differences. Individualism was a central belief of Spencer's, and in answering the Utilitarians he turned to a theory which at once provided a sufficient number of variables to account for individual differences and made the context for the study of man that of biological adaptations rather than mind in general. That theory was phrenology. But Spencer's individualism was coupled with another basic belief in social progress, and the faculty psychology of phrenology was a static one that allowed for only partial modifications as a result of experience. After all, phrenology had been
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derived by Gall in explicit reaction against naive sensationalism, and Gall had postulated innately given instincts as the basis for his faculties. Thus, Spencer's adaptive view of man and his organic view of society gave no promise of social progress. In search of this he turned to another psychological theory in biological form: Lamarckian evolution. Lamarck's theory, you will recall, had two aspects: an inherent tendency to progress in life, and perturbations of this due to the recalcitrance of the environment. The secondary factor led organisms to acquire structural modifications as a result of striving, and these were passed on to the next generation. I want to stress these two aspects because what most of us mean by "Lamarckian" evolution is the version of the theory which became popular once Spencer got through with it. He conflated the two aspects of Lamarck's doctrine and made the inheritance of acquired characteristics the mechanism of inevitable biological and human progress.
Notice that the "Lamarckian" aspect of Lamarckianism was derived from continental expressions of the associationist psychology - the tradition inspired by Condillac and united with biology and physiology by the French ldéologues. Spencer set aside his former belief in the faculty psychology of phrenology and adopted the associationist psychology as expounded by J. S. Mill in his Logic. He had developed a renewed interest in psychology through his friendship with G. H. Lewes, and when he decided to write a book on the subject, he drew on Mill's expressions of the Hartlean doctrine. The heart of Spencer's Principles of Psychology (1855) was Part III, in which he extended learning by association from the experience of the individual to that of the race, and made this the basis for biological evolution. Two years later he presented a general theory of progress based on evolution, which was extrapolation from the inheritance of functionally produced modifications according to the mechanisms of associationist psychology. After publishing this essay, entitled "Progress: Its Law and Cause," he further generalized his theory in First Principles (1862), and this contained the foundations for his synthetic philosophy as applied to psychology, education, sociology, and ethics. It also provided the basis for much of later functionalist theory in psychology, sociology, and anthropology as well as for so-called Social Darwinism in political theory. (It is worth adding parenthetically that it had important direct influences on neurology
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through the work of John Hughlings Jackson who, in turn, had an important influence on certain of the assumptions of Freud's psychoanalytic theory.) My reason for reiterating the history of Spencer's intellectual development and some aspects of his influence is to draw attention to its roots in two psychological theories: phrenology and associationism, placed in an evolutionary context and then reapplied to society in the form of the organic analogies which have been central to functionalist thought in the behavioral and social sciences. If there were space to pursue these issues further, we might explore the role of psychological theories in political and social thought - for example, in Walter Bagehot's conservative Physics and Politics and in John Dewey's liberal theories of industrial democracy. But instead of pursuing the influence of psychological conceptions further outward into society, I would like to look briefly at a still deeper level of scientific thought.
VI
There is still another way in which psychological conceptions played an important part in the nineteenth-century debate. Once again, the issue is not straightforward. The domain of this influence was the philosophy of nature, with particular effect on the concepts of "cause" and "force." This aspect of the debate is very elusive, and most scholars have only seen one bit of it in the epistemological debate between William Whewell and J. S. Mill on induction. This controversy, however, was only the tip of a very large iceberg that has been investigated by Roger Smith. In an extremely interesting doctoral dissertation on "Physiological Psychology and the Philosophy of Nature in Mid-Nineteenth Century Britain," he discusses a network of ideas and influences which involved debates on the role of touch in learning (going back to Berkeley), the organic sense (or "muscle sense"), the principle of the conservation of energy, and the concept of force itself. I am not competent to summarize his very illuminating findings, but it is clear from his research that a number of ideas were exploited in psychology, physiology, epistemology, and the philosophy of nature in an effort to overcome the problems raised by Cartesian mind-body dualism in the course of the period of the evolutionary debate. Putting the issues very crudely, there seem to have been two camps, one of which was phenomenalist in its approach and
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used a Humean conception of the association of ideas to argue that science can only be concerned with the constant conjunctions of phenomena. Phenomenalists argued that the concepts of cause and force were, as far as science was concerned, not amenable to further analysis. The other group, represented by some of the arguments of the Scottish School, by William Whewell, and by the later thought of A. R. Wallace, wanted to be anthropomorphic about nature and to project a dynamic view. Thus, they argued that the concept of cause referred to a power behind the phenomena, while the concept of force was not only derived by analogy from the concept of human intention but also implied will in nature. As Wallace said, "All Force is probably Will-Force." Proponents of this view were very much in sympathy with spiritualism and other manifestations of alleged forces behind the phenomena of nature which might bridge the gaps between mind and body, human will and mechanism, dynamic nature and dead nature. I do not want to pursue this issue further except to say that Dr. Smith seems to me to have opened up a whole new dimension of research which promises to help to show the real connections among psychological, philosophical, scientific, social, and popular theories in the period. He has shown that below the surface of the histories of psychology, biology, and related disciplines, as hitherto written, lies a much more potentially illuminating field of research in which psychological ideas were fundamental.
I have tried to shed light on three roles for mind in the evolutionary debate. My first pass at the problem produced a puzzling set of negative findings. Issues that appear central from the point of view of hindsight play a surprisingly small role in the great debate on man's place in nature. The opponents of scientific naturalism about man were not prepared to discuss in detail what they were not prepared to concede in principle, while the proponents were working with a set of overlapping conceptions which only came into focus after evolutionism had gained the center of the debate, and the burden of proof had shifted to the opponents. A second view of the same debate reveals that psychological conceptions played a central role in social theory and in the theoretical assumptions of the evolutionists and those who influenced them most. Thirdly, I briefly reported that at the level of the philosophies of nature which underlay the scientific ideas, not only of psychologists but also of physiologists, evolutionists, and
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philosophers, psychological conceptions appear to be fundamental. It seems clear that in the nineteenth-century debate there was an intimate mixture of psychological, social-philosophical, biological, and theological issues. These were linked with basic beliefs about man, nature, and society which were themselves playing an important role in the period. Those of us who find ourselves cut off as professional psychologists or historians of psychology from the contemporary mainstream of social and political issues can perhaps learn something from the earlier debate. It is only by taking a narrow and superficial view of that debate that the isolation of psychology can be made to appear real. It wasn't actually so isolated. It was engaging in scientific, philosophical, theological, political, and ideological work.
It seems to me that the task of a critical history of psychology is to use historical research to help us to consider the work that our own research and theoretical conceptions are doing, to evaluate that work, and then to debate what work we think we ought to be doing. That, of course, is a political question, but if we ponder both the negative and positive roles of psychology in the evolutionary debate, we may begin to see that it has always been political. Conceptions of psychology lie at the center of debates on man's place in nature. Such debates, however, are at the same time fundamentally concerned with a person's place in society and - overtly or covertly - with the putative desirability and possibility of alternative social structures.
Psychology is never sequestered. It is only that its students, teachers, and researchers are more or less self-conscious and critical about the actual roles which their theoretical and applied scientific activities are playing in the maintenance or transformation of conceptions of nature, human nature, and society.