Chapter III: Introduction: §1 (1)

No one who is familiar with contemporary thought can have failed to recognize two characteristics which have emerged into prominence during the past two decades. With increasing elaboration of its logical technique, science has been brought into apparently irreconcilable conflict with common sense. The result is that scientists, uneasy in the realization of this conflict, are seeking to establish a new working relation between science and philosophy. This _rapprochement_ has been brought about especially through recent progress in physics. It will not be possible to predict its outcome so long as the physicist claims to speak for science as a whole. In this introductory essay I propose to discuss in a somewhat discursive and preliminary way how far the conflict between science and common sense is apparent rather than real, and to indicate the special need for reviewing the progress of modern biology in its philosophical bearings.

At the present time few biologists are anxious to court publicity in the field of philosophic controversy. Those who do so are rarely numbered among the ranks of those who are still actively contributing to contemporary progress in biological enquiry. Those who are actively contributing to the advancement of biological knowledge show little disposition to commit themselves to far-reaching generalizations. There has emerged from the morass of speculation associated with the rise of the evolutionary hypothesis a recognition of the paramount importance of painstaking quantitative study of limited aspects of vital phenomena. This attitude is a salutary one. It does not signify that biology is passing through a phase of stagnation. On the contrary current biological discoveries contain the germ of philosophical issues which may prove to be as revolutionary as Relativity and as repugnant to common sense. In the essays which follow I shall confine myself to accredited experimental data. I do not pretend that all or even a majority of biologists will agree with my interpretation of their philosophic significance.

There is no novelty in asserting the need for incorporating the contribution of biological science in a modern philosophical outlook. Herbert Spencer and the Evolutionists prepared the ground fifty years ago; but they failed to lay emphasis on the methodological aspect of biological enquiry. The methods and not the results of biological science are specially significant to philosophical discussion. In putting forward my own views upon the nature of life, it is not the results of biological enquiry, but the methods which I propose to discuss in the first series of essays in this volume. In contrasting the methods and concepts of physical and biological science, I shall sometimes draw inferences which will not commend themselves to the judgment of biologists for whose contributions I entertain a lively respect. I shall not be surprised to be told that my forecast of the outcome of biological enquiry is pretentious, and that my philosophical conclusions are in conflict with common sense.

At an early age I abandoned the conviction that scientific hypotheses must conform to the requirements of common sense. When I was a boy, there used to be in Portsmouth, the town of my nativity, a public figure by name Ebenezer Breach. Mr. Breach was a philosopher. To be precise he described himself as “Natural Astronomer and Poet.” In that he belittled his gifts. Of his poetry I shall say nothing, save that he stated the qualification “poet by Royal Patronage” in his fascinating brochure _Twenty Reasons against Newtonianism or The Universal Challenge to Unnatural Science_. This was sold for the modest price of twopence sterling. As his contribution to modern thought may be unfamiliar to many cultivated people who were not born in Portsmouth, I propose to quote the first of his twenty reasons as representative of the system he develops:

“Because the earth has no axis, therefore nothing on which to
revolve, an imaginary mathematical line is substituted. But no
solid body could revolve on an imaginary axis or line. It is an
imaginary cause which can only produce an imaginary effect, so all
that follows the cause must be imaginary. If anything be placed on
the top of a revolving body it will fly off at a tangent.”

From this you might infer, wrongly it happens, that Mr. Ebenezer Breach earned a comfortable livelihood as Regius Professor of Moral Philosophy in an authentic University. He had in fact chosen to bear witness to the hope that was in him by the only alternative which a harsher economic destiny had imposed. Every Saturday night he addressed a handful of half-intoxicated seamen, tired commercial travellers, adventurous nursery maids and irreverent pupil teachers foregathered on the sea-front. There he occasionally succeeded in selling a copy of the _Twenty Reasons_, and beyond this obtained, as far as I am aware, no reward in the life that now is. In spite of his erudition and distinction of person, Mr. Breach, the prophet of common sense, did not make many converts. He was less successful in his popular appeal than an evangelical competitor who used to minister to Portsmouth beach before a banner whose legend stated, “the wages of sin is death.” This banner I can still recall as, in its way, a work of art. On the foreground were displayed the theatre, race-course, public-house, dancing saloon and gaming tables along the edge of a precipice over which poor folk in a semi-incandescent condition were tumbling into a lake of brimstone and fire. It invariably drew a large crowd. I had early imbibed the notion that science like Sunday travelling, whist and dramatic entertainment is worldly, so that the gospel of Mr. Breach, who condemned science on account of its essential unworldliness, presented a new and arresting point of view. On the whole the inhabitants of Portsmouth were more interested in their souls and what would become of them after death. Mr. Breach had another competitor with more peculiar views about the soul and about life. As far as I can remember he held that the brain secretes consciousness in much the same way as the liver secretes bile, and he asserted that the soul was the shadow cast by the machine. My nurse held very definite views about his domestic life. He was a materialist, and in all probability a polygamist, if not worse. Mr. Breach who was a bachelor, the evangelist who was certainly not a polygamist, and the Secularist who was undoubtedly a bad man all agreed in one particular. Each believed that the gospel he proclaimed was common sense.

Of the Flat Earth faith Mr. Ebenezer Breach is the only Confessor and, financially speaking, Martyr I have been privileged to encounter. I cherish the recollection of his secular ministrations for a reason which is eminently relevant to everything which I propose to say about the bearing of current biological concepts on philosophical discussion. At an age when, to my way of thinking, Punch and Judy were the only serious rivals to the magnetism of his stupendous intellectual gifts Mr. Breach stands out in the sharp relief of retrospect as the Forerunner of the coming conflict between science and common sense. I have already remarked that the uneasy recognition that science conflicts with common sense has been the keynote of philosophical controversy during the past decade. Curiously enough some scientists seem to regard this as a grave disability on the part of science. They feel compelled in consequence to adopt an apologetic attitude to the claims of traditional philosophy. Perhaps this is because the protagonists of science in the nineteenth century made it their proud boast that science is nothing more than organized common sense. They therefore felt that they had the man in the crowd on their side. Even Herbert Spencer, prophet of evolution, when evolution was still a subversive doctrine, could soberly declare that “the ultimate truth of a proposition is the inconceivableness of its negation.”

Neitzsche includes this quotation in the _Will to Power_ as one of his “inscriptions over the porch of a modern lunatic asylum.” It is only necessary to mention the word Relativity to indicate how impossible it would be for a natural philosopher to express himself in similar terms to-day. The situation which has been created by progress in modern physics is not without parallel in human history. It is true that the new theories have employed an immensely elaborate and difficult logical technique. How far they can be simplified it is at present impossible to predict. Newton’s fluxions were unfamiliar to his contemporaries. The author of the _Principia_ devoted a good deal of time to a geometrical presentation of his ideas, in order to make them accessible to his generation. For more than a century after Newton’s death the calculus remained a preserve for mathematical specialists. To-day a knowledge of the calculus requisite to an elementary understanding of the theory of elliptical orbits lies within the scope of the first year’s work at a university, if it has not been acquired in the higher forms of a good school. It is conceivable that the mathematical development of modern physical theories will be simplified in the course of time. In that sense the esoteric stage through which physics is now passing may be a temporary phase. The essential feature of the conflict between common sense and physical science in this generation lies in the unfamiliarity of the new concepts. The conflict between common sense and the new biological concepts shares the same characteristic.

In Bernard Shaw’s _St. Joan_, La Tremouille asks: “Who the deuce was Pythagoras?” “A sage,” replies the Archbishop, “who held that the earth is round and that it moves round the sun.” “What an utter fool,” says La Tremouille, “couldn’t he use his eyes?” La Tremouille here calls attention to a fact that was overlooked by Herbert Spencer, by Mr. Ebenezer Breach and by those Relativist philosophers, who, being unable to convince the man in the crowd, indulge in the luxury of wondering whether the claims of scientific method have been pushed too far. Common sense is another name for what good citizens are prepared to accept without argument. Scientific ideas only conflict with common sense so long as they are still new and unfamiliar. Mr. Breach was in advance of his time in daring to criticize the Newtonian system. He was behind his time in thinking that Newton’s position could be assailed successfully with the weapons of common sense. The essential rightness of the Newtonian system had already become incorporated in British middle-class respectability. To the rising generation suckled on Mr. Wells’ _Outlines_ evolution is common sense. Two generations have elapsed since, as La Tremouille would say, any fool who used his eyes could see that a bishop was a product of special creation. The man in the crowd has no clearer notion of the logical status of the doctrine of descent than had his grandfathers who implicitly accepted the story of the Fall.

The phenomenal success of those who set out to popularize the Theory of Evolution makes it easy to overlook the circumstance that evolution was wholly repugnant to common sense within the memory of those who are still living. The outburst of public controversy which greeted its announcement has no parallel in this generation. In consequence its impact upon traditional philosophy has been far less apparent than its influence upon religious dogma and social theory. The younger generation of biologists cannot recapture the first fine raptures of enthusiasm which their elders experienced. The prevailing attitude is to welcome a return to the complacent dualism of pre-Darwinian days, when scientists did not meddle with philosophy and metaphysicians conceded to scientists the right to go to the devil in their own way. Although this view is widely held, I do not believe that the philosophical implications of evolution have ever been thoroughly explored; or that it was possible to do so, while the study of animal behaviour was still dominated by the language of introspective psychology. By explaining the secular origin of philosophers Darwin bequeathed to us the task of elucidating the anatomy of philosophy.

In the opening years of the present century, science had already lost that truculence which one associates with the generation of Huxley and Tyndall. It had surrendered its tradition of fearlessness and candour. Academic philosophy, liberal theology and utilitarian science went their placid ways without mutual interference. Bergson, a philosopher more widely known than Mr. Ebenezer Breach, had cast a pebble of _belles lettres_ into the mill-pond of compromise. The indifference with which it was greeted by those engaged in the task of placing the evolutionary problem upon a secure foundation of experimental data is a measure of the esteem which they entertained for it. It has been interpreted as assent by some contemporary writers who are not themselves biologists. In _Science and the Modern World_ Dr. Whitehead even speaks of Bergson’s “instinctive grasp of modern biology.” A modern biologist engaged in the study of behaviour would refer with greater caution to Madame Blavatsky’s instinctive grasp of modern astronomy or Mahatma Gandhi’s instinctive grasp of modern economics. He would regard the instinctive grasp of any branch of scientific knowledge with more suspicion than approval. No biologist has undertaken the task of examining the philosophical implications of Darwin’s doctrine in the light of contemporary progress in the experimental analysis of living matter.

§2

Under the influence of Hegel, academic philosophy left the scientist to his own devices. To-day the physicist has again driven the idealist philosopher out of his retreat. He has compelled him to take account of a conceptual world which we all recognize whenever we consult a railway time-table or book a passage in an ocean liner. Secure in the prospect of fresh philosophical victories, the astronomer surveys the world with a blind eye to the microscope, and magnanimously dictates the new territorial frontiers of science and moral philosophy to the advantage of the latter. It has been customary in the past, and therefore common sense, to assume that the issues with which moral philosophy deals are more fundamental than those which fall within the scope of natural science. It is an assumption which, whatever its meaning, does not hamper the advance of pure physics; but the biologist is not bound to accept this convention when it restricts his own field of enquiry. A philosopher is a particular kind of organism. Philosophy itself might therefore be regarded as an aspect of the behaviour of a piece of living matter. The study of the properties of living matter is the province of the biologist. From this point of view the study of biology is more fundamental than the pursuit of moral philosophy.

The physicist brings to the discussion of philosophy the discipline of an older branch of enquiry with a more elaborate logical technique than that of biology. His claim to speak for the whole field of science should be scrutinized with a critical eye. I am sure that Professor Eddington will agree with me, when I say that the biologist has a specific contribution to make to what he has aptly called the “world symposium.” I am also confident that many biologists will agree with me, when I state that the contributions of the Relativist philosophers rarely display a profound understanding of the kind of problems biologists are now attempting to solve, and the way in which the modern biologist sets about his task. A quotation from Mr. Sullivan’s _Bases of Modern Science_, a stimulating and provocative book, will illustrate my meaning. Mr. Sullivan, whose physics I do not venture to criticize, states: “The primary concepts in terms of which the science of physics is constructed... have to be supplemented by others in the science of chemistry, and for the sciences of life and mind, are so far from being sufficient, that they have hardly yet been found to be relevant.” Half a century has passed since the concept of chemical affinity was annexed by thermodynamics, and the most conservative physiologist could hardly refrain from ridiculing the latter part of this quotation. Professor Eddington himself has adopted the “Principle of Indeterminacy” as an _ad hoc_ hypothesis in a limited field of enquiry. From it he proceeds to draw conclusions about human responsibility and the doctrine of free will. These are topics which lie nearer to the province of biology than physics. It would be well to await the verdict of biological science before accepting inferences of so far reaching a character as those which Professor Eddington has advanced.

By emphasizing the conflict between science and common sense Relativity has engendered a new interest in the relation of science to moral philosophy. To view that relation in its proper perspective the concepts of modern biology must supplement the concepts of modern physics. I am not suggesting that this need is overlooked by those who are not biologists. Dr. Whitehead has gone so far as to advocate replacing the traditional physical idea of matter by the biological concept of organism, or as a modern biologist might prefer to say, behaviour. When he expresses the hope that this will assist to “end the divorce of science from the affirmations of æsthetic and ethical experiences,” it is clear that his conception of the nature of biological enquiry dates from Herbert Spencer and differs from that which contemporary biologists would generally be willing to accept. Owing to the separation of descriptive from experimental biology, a separation for which the evolutionists were pre-eminently to blame, a well-informed interest in the study of living matter is more rare among physicists of our period than it was in the days of Robert Hooke and Boyle or of Euler, Lavoisier, and Laplace. I am convinced that very few scientists who are not biologists--perhaps no professional philosophers--possess a clear notion of the way in which the modern experimental biologist approaches the study of the organism and the results at which he aims.

I have already suggested that there are special reasons why the concepts of biology stand in a more intimate relation to the scope of moral philosophy than do those of physical science in the restricted sense. It is difficult to define the meaning of philosophy without implying a particular point of view about the limitations of human knowledge. There are as many different definitions of philosophy as there are different schools of philosophical opinion. From the point of view of the materialist a Hegelian is a sea lawyer. From the point of view of the subjective idealist a materialist is not a philosopher at all. If there is anything which all the two and seventy jarring sects would agree to regard as a problem of philosophy, it is the Nature of Life. If we are to avoid making any unjustifiable assumptions about the nature of knowledge, we must for the present define a philosophical discussion of the Nature of Life as the most comprehensive treatment of the problem. It does not necessarily follow that there is any essential difference between a scientific and a philosophic enquiry in this sense.

When people first hear their own voices recorded by a gramophone, it is well known that they are often--like myself--a little humiliated, and generally somewhat surprised. I once had occasion to witness an instructive incident which occurred in the phonetics department of the University of Cape Town. A gramophone record of three men engaged in a conversation was prepared. None of the three participants had previously listened to a record of his own voice. When the record was completed each man agreed that the voices of the other two were faithfully recorded. Each man denied that his own voice had any semblance to its representation by the recording instrument. This simple experiment in human behaviour illustrates what I shall later call the distinction between the _private worlds_ and the _public world_. It also illustrates a fundamental divergence of outlook which distinguishes two tendencies in philosophical discussion, and makes it difficult to give any definition of philosophy satisfactory to all parties. One school of philosophers defines a good record as a record which on the whole faithfully conveys the impression of human voices. The philosopher of the opposing school feels that it ought to be possible to manufacture a record which will faithfully represent the voice of his opponent, while at the same time registering his own voice as he hears it himself, when he is speaking, and would prefer other people to hear it.

This distinction has an interesting history which will be discussed in the third series of essays in this volume. Greek speculative philosophy had its first beginnings in a secular curiosity about Nature. Science and philosophy were thus one and the same thing to Thales, to Empedocles or to Democritus. In Greek thought speculation was not sufficiently disciplined by sustained observation of Nature. For that reason it gave birth to innumerable conflicting hypotheses which could never be made the subject of decisive tests. Out of this confusion of conflicting ideas was born a reaction against science. Philosophy turned from the slow and tedious task of examining the actual world to the more facile and pretentious pursuit of an ideal world. In the person of Plato it forfeited its secular temper. Science was introduced into modern Europe by the Arabs, who assimilated the secular curiosity of the Greeks. Ecclesiasticism seized upon the speculations of the later Greek philosophers to provide a rational basis for theological dogma. Since mediæval times scientists have submitted to an arrangement which gives to those who have not studied Nature the right to supervise the logical status of their conclusions. The stability of this arrangement has been maintained by the circumstance that human beings are far more interested in themselves than in any other material objects. Greek materialism declined, because it could not satisfy man’s curiosity about himself. The success of its rival was not due to its ability to settle the problems of human nature and social conduct. It succeeded because human nature demands a forum for the ventilation of its grievances. Science has been most successful in the past in dealing with inanimate things. Only in comparatively recent times has the phenomenal success of scientific method, fortified by the secular influence of Darwin’s teaching, encouraged the belief that it might be applied to the study of man’s behaviour and social organization. The belief that a philosophical discussion of the Nature of Life lies beyond the province of the biologist is due to centuries of subservience to a tradition which has identified philosophy with the interests of statesmanship and ecclesiasticism. If the method of science is applicable to the study of how statesmen and theologians behave, it is legitimate to undertake a discussion of the nature of life without assuming that the biological standpoint must be reinforced by the discipline of scholastic philosophy.

There is a further assumption which we need not make in our enquiries into the Nature of Life. We need not presume like Socrates that all questions about life are permissible. A proper respect for our own limitations is as essential to philosophy as to sanity and modesty in everyday life. It is only possible to formulate questions in the right way when we already have at our disposal a good deal of information relevant to the correct answer. This was not recognized by the materialists of the nineteenth century when they attempted to give a common-sense solution of the Riddle of Life. To-day it is customary to refer to materialism as an exploded fallacy. If instead of looking at the way in which the materialist attempted to answer the man in the crowd, we examine the way in which he attempted to answer the questions which he himself propounded, the explosion of the fallacy is not so encouraging to traditional beliefs. The term materialism, when it is not employed like Bolshevism as a term of abuse, is loosely applied to a constellation of beliefs, some of which concern the Nature of Life and some of which concern the Nature of Knowledge. In the latter sense materialism implies the conviction that the only genuine knowledge is that which can be gained by pursuing the method devised by scientists for the study of what are ordinarily called material objects. If this conviction is carried to its logical conclusion, a discussion of the Nature of Life in language which is intelligible to the audience of Mr. Breach or his Secularist competitor is impossible. The materialist who attempts a common-sense solution of the Riddle of Life is inconsistent with his materialism. It is his inconsistency and not his materialism which is an exploded fallacy. Common-sense materialism, the materialism which is an exploded fallacy to-day, was based on the belief that a plain answer to a plain question is the inalienable birthright of the plain man. Secularist rationalism was the offspring of Protestant democracy. Protestant democracy is suspicious of the expert, who is the person who knows that there is a technique of asking questions in the right way as well as a technique of answering them in the right way. Perhaps Xanthippe, who has become the symbol of a nagging wife, realized this profound truth more clearly than Socrates. Perhaps her short way with introspective philosophers was based on a considered recognition of human frailty, and experience of children.

An intelligent child of three once asked me to tell her the colour of Wednesday. To the more sophisticated adult the question is ridiculous, though I suppose the theosophist would regard it as permissible. Metaphorically speaking, the habit of asking the colour of Wednesday is not exclusively confined to children. Thousands of years ago human beings began to associate particular sounds with objects around them, so that these sounds became signals for activities. These activities became increasingly more complex as articulate speech became more elaborate. Gradually human beings ceased to employ a separate symbol for every object around them. They began to condense and economize, abstracting separate properties. It became no longer necessary to have separate words for white cow, black cow, white horse and black horse. In effecting this economy it was inevitable that new words with no clear relation to experience were often invented. Common language the world over is burdened with words which effect no economy of discourse. Anyone who has not realized this may perform the simple experiment of asking six educated people to define in writing on a folded slip of paper the meaning of the word _sincerity_. With the coming of civilization man invented a new form of symbolism, the language of science. In spite of immense social inertia this symbolism has become more and more important, because of the tremendous power for controlling nature which it has given us. In the invention of this new language not only sustained observation of nature, but active interference with nature, or experiment, is enlisted in the process of abstraction.

Because common language and the language of science are not the same thing, there never can be a plain answer for the plain question of the man in the crowd. There can only be a familiar one. In any restricted field of scientific enquiry confusion of thought is avoided by the introduction of new symbols to denote new experience, or a preliminary re-definition of old symbols, if these are employed. So long as the chemist is only concerned with the reducing power of a particular sugar, it is sufficient for him to describe it as dextrose. When he directs his attention to the optical properties of the sugars he finds this symbol no longer adequate to define a homogeneous class, and distinguishes between α dextrose, β dextrose and so forth. When scientific hypothesis so broadens its channels as to merge into the general current of human thought, the scientist finds himself dealing with matters for which there already exists a vocabulary, but one that has none of the precision of scientific nomenclature, one called into being by an approach to experience which has none of the disciplined restraint which scientific method imposes. That is why the practising scientist is sometimes compelled to treat the conundrums of humanistic philosophers like the question of the child who wanted to know the colour of Wednesday. Concerning those things about which we talk most our language is apt to be least definite.

§3

One of the things about which we talk most is life itself. A discussion of the Nature of Life presupposes that we mean something quite definite, when we use the term life. The familiar lines of Mr. Belloc suggest a helpful analogy to illustrate the nature of a scientific definition:

“Here you may put with critical felicity
The following question, ‘What is Electricity?’
‘Molecular activity,’ say some.
Others remain silent or are dumb.”

What is electricity?--is a plain question. It is only possible to give it an intelligible answer when we translate it into the form, what conditions determine electrical phenomena? A scientific concept is a label for a class of properties which can be investigated scientifically. Though this happens to be a cardinal doctrine of modern logicians, it is also a commonplace of scientific thought, when undisturbed by ulterior considerations. It is a commonplace which is constantly overlooked by biologists as well as laymen in a discussion concerning the nature of life. The temptation to overlook it is assisted by the custom of spelling nature and life with capital letters, a practice to which what the Melanesians call _mana_ adheres. The only intelligible significance of the word Life in scientific discussion is to denote collectively the properties of living[1] things.

The word life is variously employed in common language. To Mr. Mantalini life is one demmed {sic} thing after another. Every biological student is familiar with the experiment of removing a frog’s heart from its body, maintaining its beat by perfusing it with a suitable saline medium, arresting its rhythm and restarting it by changing the constituents of the medium. This can be performed repeatedly for many hours after the owner of the heart is, legally speaking, dead. The layman confronted with this commonplace of the laboratory invariably asks with some show of bewilderment, “Is it alive?” It is extremely difficult to answer him in words he will understand. He has been accustomed to think of an organism as a whole, just as we think of solid matter as a whole. Unaided common sense does not easily grasp the notion that the frog’s heart displays the characteristic properties of living matter, after the frog, considered as a whole, has ceased to display those characteristics of living matter which we associate with whole frogs, when we say that they are alive.

In biological discussion the nature of life can only be understood to mean the characteristic properties of living things, how they are related to one another and to the properties of non-living matter, how they have come into being. To those who are accustomed to thinking in abstract nouns and capital letters this way of defining life will seem rather like the well-known definition of an archdeacon as a man who discharges archidiaconal functions; but if life is only a convenient label for the properties of living matter, we have foreshadowed an important conclusion. Those who declare that materialism is an exploded fallacy are usually those who deplore the judicial separation of science and moral philosophy. If they entertain the hope that biology is likely to effect a restitution of conjugal rights, they evidently imply that life to the biologist means something more than the properties of living matter. They assume that a biological concept of life contains other implications of its use in common language.

The source of this confusion is easy to understand. The biologist can no more avoid using the word life than the physicist can avoid using the word matter in a loose and arbitrary sense in everyday conversation. Whatever meaning the biologist may attach to the term life, when he is exercising his domestic and political activities, there is only one legitimate manner in which he can employ it in his capacity as a scientist. Much discussion between the opposing schools of vitalists and mechanists is utterly barren, because this fundamental issue is not clearly defined at the outset. The vitalist can legitimately attack the mechanist by pointing out that living things have characteristic properties other than those which the mechanist attempts to analyse. If he does so, he must specify what such properties are. In the laboratory the biologist carries out his work on the same lines, whether he calls himself a vitalist or a mechanist. On the platform he may, and frequently does, overlook this. The layman may thus acquire a disproportionate estimate of the extent to which biologists differ among themselves about fundamental issues.

That biologists are still less unanimous than chemists in the hope of resolving, in more universal terms, concepts traditionally restricted to their own fields of enquiry, may be attributed to the complexity of their subject matter. Biology is a younger science, and a vast amount of purely descriptive work was necessary, before it was possible to formulate the mechanical problems which living matter presents. This task requiring considerable specialization in the descriptive study of the exclusively geometrical aspects of the configuration of living systems unhappily became divorced from the more fundamental issue of biological enquiry. The physical analysis of the properties of living matter is a problem necessarily spatio-temporal in its extension, experimental in its method, and quantitative in its grammar. The spectacular success of evolutionary speculation during the nineteenth century preceded the birth of quantitative and experimental researches on inheritance and variation, giving descriptive biology a reflected glory on account of the far-reaching cosmological consequences of the doctrine of descent.

By encouraging the hope of reconstructing the pedigree of mankind, Natural Selection widened the gulf between descriptive and experimental enquiry; and provided a satisfactory modus vivendi for two diverging and independent schools of research. Anatomy claimed the relation of one type of living being to another. Physiology concerned itself with the relation of living matter to inanimate objects. During the present generation evolutionary problems have emerged to the forefront of experimental enquiry. Heredity and variation are no longer axioms with which the taxidermist and the osteologist can conjure unchallenged. Experimental biologists are grateful to those who have compiled the Who’s Who of the Animal Kingdom. They refuse to concede that the execution of this task implies a profound understanding of the principles of political economy. Naturally the anatomist and the field naturalist view the change with a jealous and suspicious eye.

Biologists agree among themselves in recognizing that the approach to the organism as a physical object has led to many valuable discoveries; and that the application of physical methods to the study of the organism permits us to make many predictions about the behaviour of living systems with as much confidence as we have in predicting other secular events. In so far as recent investigation has probed into phenomena which it has been customary to place beyond the limit of applicability of physical methods and concepts to the analysis of the properties of living matter, it is not surprising that many biologists have failed to take stock of the situation. They may simply deny that certain aspects of the behaviour of organisms can be treated successfully by the traditional methods of experimental physiology. If they do, it should be sufficient to set forth the new evidence at our disposal. When they go further and assert that certain characteristics of living things properly belong to the sphere of traditional philosophy, it is permissible to entertain the suspicion that they share the all too human desire to be _certain_ rather than to _know_.

The chief source of disagreement between different schools of opinion in any discussion of the Nature of Life arises from the difficulty of defining another concept which is intimately connected, but not necessarily co-extensive with, that of life itself. It has been customary in the past to assume that the concept of _consciousness_ defines a field in which the methods of experimental physiology break down and require to be supplemented by the method of introspection. In so far as it bears on the Nature of Life this implies the possibility of identifying and specifying in living systems characteristics to which the term consciousness directs attention. It is impossible to avoid disagreement in connexion with this concept without recognizing a fruitful source of confusion. The statement “I (N or M) am a conscious being” has a formal relation to the statement “All men are conscious beings” like the analogous statement “Mr. Bertrand Russell is a conscious being,” so long as it is understood that I and Mr. Bertrand Russell are both single valued and members of the class “men.” From this it follows that any implication of the first proposition which is not implicit in the second defies logical analysis and therefore eludes philosophical enquiry. For the purpose of philosophical discussion “I am a conscious being” contains nothing that is not implied by saying that “all men are conscious beings.” I shall use the term _public_ to signify this way of looking at the concept of consciousness. Any residuum of the first proposition which cannot be formally identified with the third and shown like it to be included in the second and more general proposition is a _private_ affair of the individual. If we find that modern physiology has undertaken to investigate those characteristics of the behaviour of living systems associated with the term consciousness in its public sense, a new horizon of philosophical discussion is unfolded. If physiology is more successful than introspective philosophy in defining predictable conclusions about living behaviour, we have no need to go outside the data of physiology for the materials of a comprehensive discussion of the Nature of Life. A philosophical discussion of the Nature of Life will only be more comprehensive than a biological discussion of the Nature of Life in the sense that more attention will be paid to the methods of enquiry adopted.

Between two extreme schools of opinion existing at the present day the issue, in so far as it is a tangible one to the practising biologist, is thus defined by Dr. Haldane in his recent Gifford Lectures.

“We can of course leave the characteristic peculiarities of
conscious behaviour out of account, and regard persons from a
purely physical and chemical point, as weighing so much, as
yielding certain amounts of various proteins and other chemical
substances, distributed in a certain way, and as in various ways
continually converting potential into kinetic energy. This mode
of regarding persons is of great practical use for engineering
and other purposes, _but tells us nothing, however far we may
extend it, regarding the distinctive_ characters of conscious
behaviour...” (italics inserted).

In this passage Dr. Haldane is perfectly definite in stating where, as he believes, the methods of traditional physiology cease to be applicable. It is peculiarly felicitous that he uses the term conscious behaviour rather than consciousness in this connexion. If we find reason to believe that “conscious behaviour” can be analysed with reference to a space-time framework by the methods of physical science, Dr. Haldane’s attack on the mechanistic position falls to the ground except in so far as he can refuse to capitulate until the problem has been reduced to a question of pure physical chemistry. In the succeeding essay on The Mechanization of Consciousness I shall endeavour to show that in our generation the work of Pavlov’s school has successfully tackled, for the first time in history, the problem of what Dr. Haldane calls “conscious behaviour” in non-teleological terms. It has reduced it to the investigation of the conditions under which new reflex systems are brought into being.

In _Science and the Modern World_ Professor Whitehead states that the “effect of physiology” on philosophical discussion has been “to put mind back into nature.” I presume that he is referring to the traditional distinction between reflex activity and voluntary behaviour. It is true that physiology has accepted this distinction which it inherited from the dualism of Descartes; but traditional physiology never attempted to probe deeply into the nature of voluntary behaviour. It was content to investigate reflex activity, and concede the prerogative of discussing the characteristics of conscious behaviour to moral philosophy. _Experimental physiology like experimental physics is an ethically neutral science._ If Pavlov has reduced the problem of conscious behaviour to the same level of discussion as the problems of reflex behaviour, the traditional distinction between reflex and voluntary activity has ceased to define the boundary at which physiology ends and moral philosophy begins. If the investigation of the characteristics of conscious behaviour can be brought within the scope of an ethically neutral method, we must abandon any hope that biology can assist to end “the divorce of science from the affirmations of æsthetic and ethical experiences.” If the Relativists can say that modern physics has given materialism its death blow by referring solid matter to an atomic nexus of conceptual fields of force which only exist in our consciousness, the physiologist can add that modern biological enquiry is disintegrating consciousness into an atomic nexus of reflex arcs. If modern physics has shown that we can no longer think profitably of solid matter as existing in the way in which it presents itself to common sense, modern biology is showing that for the purpose of profitable discourse mind itself does not exist as the essential unity which it assumes to common sense. If the advance of science has disposed of the older forms of materialism, it is also disposing of the traditional forms of idealism and dualism at the same time.

Biological science no less than physics is opening up new fields for exploration in philosophy. The new approach to the problem of “conscious behaviour” involves an intellectual effort no less repugnant than the non-Euclidean space of the relativist. The new, in preference to the traditional biological standpoint, owes its sanction to the same test as that by which relativistic theories must in the last resort be assayed. A disinclination to discuss “conscious behaviour” and a tendency to assert dogmatically the possibility of reducing it to purely chemical concepts has been characteristic of the mechanistic standpoint in the past. It would seem that to emphasize the applicability of physical methods to living matter in all its aspects, a new term, free from this taint, is now needed. _Behaviourist_ has already acquired certain restricted implications, and for reasons which will be set forth in a succeeding essay I shall sometimes speak of the _publicist_ in preference to the mechanistic standpoint. Unlike the Flat Earth doctrine of Mr. Breach the publicist standpoint in philosophy is not based on an appeal to common sense.

I began these introductory remarks by calling attention to two characteristic features of contemporary thought, the uneasy recognition of the opposition of science to common sense and the renewed search for a working agreement between the claims of science and of moral philosophy. In concluding, I would add a third to which I have not explicitly referred. The scientist brought into collision with common sense has for the time being lost his former air of self-confidence. We are told that science does not deal with reality, that the external world of physics is a shadow world, that the laws of physics are only statistical generalizations, that scientific hypotheses are no more than convenient devices to aid us in the practical business of living. I cannot but feel that the solemnity of these assertions is out of all proportion to their novelty. I cannot discover why recent developments in physics constitute a specially cogent reason for reiterating them at the present moment. I am disposed to believe that some of the younger generation who have been familiar with the writings of Mach, of Pearson, of William James and of Bergson, since they first began to think about the nature of scientific knowledge, must share with me a sentiment of surprise, when told that living scientists ever seriously put forward those extravagant claims which, as we are now assured, received their death blow from the theory of a relativity and the new quantum mechanics. The apologetic attitude so prevalent in science to-day is not a logical outcome of the introduction of new concepts. It is based upon the hope of reinstating traditional beliefs with which science was at one time in open conflict. This hope is not a by-product of scientific discovery. It has its roots in the social temper of the period. For half a decade the nations of Europe abandoned the exercise of reason in their relations with one another. Intellectual detachment was disloyalty. Criticism of traditional belief was treason. Philosophers and men of science bowed to the inexorable decree of herd suggestion. Compromise to traditional belief became the hall-mark of good citizenship. Contemporary philosophy has yet to find a way out of the intellectual discouragement which is the heritage of a World War.

The physicist has abandoned teleology in his own field. He has banished the spiritual values from the domain of his enquiries. He now looks to the biologist to shoulder the task of proving that the universe is consonant with our notions of ethical propriety. I shall endeavour to show that the progress of modern biology gives no justification for the belief that such a compromise is possible. In approaching this task my aim is not primarily to advocate the mechanistic conception of life or to criticise the vitalistic standpoint. Controversy between writers of the mechanistic and vitalistic schools has too often focused attention on whether a complete solution of the Nature of Life can be found within the mechanistic framework. The more significant question is whether any solution can be obtained outside the mechanistic framework. It may be interesting to know how far the biologist has progressed in his enquiry into the Nature of Life. Philosophically it is more significant to understand what methods of investigation have permitted him to advance towards an admittedly partial solution of his problem. To show that the mechanistic conception of life is inadequate is one thing. To show that any alternative and more comprehensive view can be gained by pursuing methods other than the traditional methods of experimental biology is a more difficult task. It appears to me that the mechanist can admit every criticism which the vitalist brings to bear upon his case without weakening its essential strength. If we commence our enquiries with the assumption that it is possible to know everything, we shall be disappointed to find that the mechanistic conception of life does not--and probably never will--find an answer to every question which we may be tempted to propound. In that disappointment lies the false security of the vitalistic standpoint. It was the peculiar merit of Hume’s philosophy that he rejected the necessity of making this assumption.

In assessing the respective contributions of the biological and physical sciences to the construction of a Public World, we are investigating the existence of certain characteristics common to all branches of natural science. The method of science is not static. It is ever growing and expanding, incorporating new territories within its empire. For this reason formal definitions unfortified by an examination of the historic past tend to be superficial and barren. The origins of even the most exact sciences are deeply rooted in the soil of magic. At any stage in the progress of human knowledge particular features may be evident in more than one branch of enquiry. As time goes on fresh similarities present themselves. The exact line of demarcation between the already scientific and what is not as yet scientific is therefore somewhat arbitrary. No definition of scientific method is adequate unless it implies the recognition of a developmental sequence in which new characteristics emerge successively into prominence.

In the natural sciences, as customarily defined, it is essential that the data shall be publicly accredited by the testimony of independent observers. The observation and recording of publicly accredited data is not in itself regarded as an adequate criterion of scientific study, unless the data are arranged or classified in a particular way. Such classification makes it possible to draw inferences which extend beyond the range of the original data. The validity of the relations implied in a particular classification is referred to their capacity to permit us to predict verifiable conclusions. In practice it is necessary to classify the data of a problem in a variety of ways before it is possible to arrive at the type of classification which yields relations satisfying this criterion of validity. This circumstance assists us to draw a rough distinction between a type of enquiry which is maturely scientific and one which is in process of becoming scientific. In the older and more firmly established branches of science, it is evident that severe economy in the initial assumptions promotes the construction of hypotheses which are valid in the sense defined. Ethical values have been eliminated altogether. The same characteristics are increasingly recognized in newer departments of scientific investigation.

When every criticism of the limitations of scientific method has been accepted, the belief that philosophy can provide a means of solving the problems which lie outside the realm of scientific enquiry still remains to be proved. In the essays which form the third series of this volume, I shall endeavour to discuss whether an enquiry into the nature of reality has any intelligible meaning. With Hume I doubt whether it is possible to attach any significance to deciding whether scientific beliefs are a faithful representation of “reality.” Scientific beliefs are specially characterized by their communicability, or, to use the term which I shall employ more frequently, their _publicity_. The fundamental problem of a philosophy which does not presuppose what it sets out to establish is to find what characteristics of beliefs make them communicable. It is by examining these characteristics that we can hope to decide whether the discussion of our ethical and æsthetic predilections can yield conclusions which have the same kind of communicability as scientific beliefs, and, if that is possible, in what manner such discussion must be conducted. I shall endeavour to show that there is a confusion of meaning involved in discussing whether the experiences with which science deals are more or less real than the experiences which moral philosophy has claimed for its parish. The more modest task of deciding whether the conclusions of science have more or less communicability than ethical and æsthetic beliefs is not a problem which necessarily eludes unprejudiced investigation.

I have indicated that an enquiry into the nature of life and the nature of consciousness presupposes the necessity of formulating the problem in the right way. This task is a necessary preliminary to the analogous question, what is philosophy? The firefly emits light. When we say that we understand what animal light is, we mean that we understand what processes are involved in the production of animal light. The method of science can lay bare the structures in which luminescent materials are secreted and the physical transformation of their chemical energy into visible radiation. Animal light is an unusual characteristic of a species of insect known as the firefly. The light of reason is a peculiar characteristic of certain human beings known as philosophers. We can only say that we truly understand philosophy or the light of reason, if we understand the processes which confer upon philosophers their unusual characteristics. A philosopher brought into being by the process of natural generation develops in an environment which includes inanimate objects and other human beings. He reacts to his physical environment by growth and to his social environment by learning. If the method of science can assist us to elucidate the processes of growth, learning and natural generation, science can assist us to understand what philosophy is. The anatomy of philosophy and the physiology of philosophers are inseparable. We need not be discouraged in pursuing this line of enquiry, because the answer which science can give us at present is incomplete. It is the chief glory of science that its answers are always incomplete. The pitiful failure of introspective philosophy resides in the finality of its answers. Perhaps the most permanent influence of Relativity in the history of philosophy will prove to be the challenge it issued to the finality with which Kant enunciated the concepts of space and time.

I. THE MECHANIZATION OF CONSCIOUSNESS

“Now, in conclusion, the Method which teaches adherence to the
true order and an exact enumeration of the conditions of the
thing sought includes all that gives certitude to the rules of
arithmetic.”--Descartes, _Discourse on Method_

§1

The onus of proving that all the properties of living matter can be reduced eventually to problems in physical chemistry or, on the other hand, of denying that such will ever be accomplished, may be laid on the shoulders of those who commit themselves to rash affirmations and denials. If this were the only matter to decide, a discussion of the merits of the mechanistic conception of life could reveal nothing more than a temperamental difference between the disputants. A temperamental difference does exist. The mechanist has a cheerful attitude to knowledge and refuses to capitulate to the fear of the Unknown: the vitalist, a sadder but not necessarily wiser type, finds balm in the limitations and failures of human effort. The average biologist, who has little sympathy either for the heroic or the desperate point of view, maintains a detached scepticism.