First , scientific research in physics and chemistry is not a process whereby the mind explores a world of matter existing independently of itself .sx Scientific thought is an activity which substantially affects the nature of that which it studies .sx It abstracts , classifies , analyses , takes to bits , and , in so doing , it modifies , if it does not actually destroy , the concrete reality with which it purports to deal .sx Secondly , physics is , therefore , to some extent subjective .sx It used to be urged that psychology , regarded as the study of mind , was not and never could be scientific , for the reason that the only mind to which the psychologist had access was his own .sx By introspection , it was thought , he could acquaint himself with its contents .sx But the mind which he introspected was the same as the mind by means of which the introspecting was being performed ; it was , therefore , necessarily affected by the fact that it was being made the object of inquiry , with the result that it was extraordinarily difficult for the psychologist to avoid finding what he expected to find .sx It now appears that physics is in much the same plight .sx For the subject-matter of physics , like that of psychology , is modified and moulded by the mental activity involved in its exploration .sx The inference is , as Mr. Joseph Needham puts it , that `the world as seen by science is not the world as it really is' .sx It used to be thought that physics was a process of discovery or exploration , whereby the external world was by a sort of revelation revealed to the mind of the enquiring .sx physicist .sx But , to quote again from Mr. Needham , 'The concept of Revelation has been removed from science' .sx Hence , the suggestion now made in many quarters that science is essentially a form of art .sx It is an imaginative picture constructed by the human mind of the workings of the universe , not , as it used to be thought , a photographic representation .sx And , inevitably , the picture will bear upon it the imprint of the personality of the artist .sx This is the view of their activities which many eminent scientists seem increasingly disposed to take .sx `I found that not only Einstein , but also Planck and Schrodinger fully recognised the subjective element in science .sx Planck in particular .sx .. regards science as a constructed work of art , expressing a certain side of man's nature .sx ' Thirdly , science does not tell us the whole truth about things .sx It only provides us with partial truths about those aspects of things which it has selected for treatment because they are amenable to its methods .sx It used to be customary to divide subjects into those with which science was competent to deal , and those , such as music , or religion , with which it was not .sx This division is misleading .sx Science is competent to tell us something about everything ; but it cannot tell us the whole truth about anything .sx Moreover , in regard to many things the information which it has to offer is not the kind of information which matters .sx Hence , the mechanist theory of the world , although it may give us important information about the way in which things behave , is no longer regarded as containing the exclusive truth about the world .sx Fourthly , there are avenues for the exploration of the universe other than that of science , notably through the aesthetic , the moral and the religious consciousnesses .sx These avenues are not only as valid as the approach through science ; they may be even more important , since while , as we have seen , science does not give us information about the reality of things , or rather about the reality behind them , art and religion may do so .sx Some scientists indeed , for example , Schrodinger , seem to regard science as a comparatively unimportant means of access to reality .sx `In the new universe , it appears , our religious insight is granted as great validity as our scientific insight .sx Indeed , in the opinion of the greatest creator of them all ( Einstein ) our religious insight is the source and guide of our scientific insight' .sx This is not to say that science , which formerly was thought to disprove religion , now supports it ; merely that it no longer affords any reason for thinking it to be untrue .sx It may supplement but no longer contradicts the deliverances of the religious consciousness .sx Science in fact has cleared the boards of the universe for religion , but it has no contribution to make to the writing of the play .sx CHAPTER V .sx CURRENT THEORIES OF LIFE AND MATTER .sx Author's Bias .sx This chapter and the next must be prefaced with a note of warning .sx Of all the chapters in the book they most nearly represent the views of the writer .sx It may , therefore , well be the case that the standard of impartiality , which I have endeavoured to observe throughout this book , is not maintained ; that I have attributed importance to theories less because they are current than because they are mine , and suggested trains of argument which are invested with no greater authority than the approval of the writer and have no origin save in his own mind .sx It is well for all parties that this warning should be borne in mind ; it testifies to frankness in the author and induces caution in the reader .sx We have seen in the last chapter how materialism has broken down in physics .sx We have now to consider how it has fared in the realm of biology .sx Here , too , the history of recent thought has been largely the history of its supersession ; in fact , the nineteenth-century view has been largely abandoned , but the abandonment has been less spectacular than in physics , and the evidence which has been responsible for it is neither so positive nor so unassailable as that which was considered in the last chapter .sx There has been a growing realisation that something more than the materialist hypothesis is required to account for the development and evolution of life and the difference in behaviour between living organisms and non-living matter .sx This realisation has in its turn generated a number of theories which , seeking to interpret the peculiar character and behaviour of life , and originating , therefore , in the realm of biology , tend to take on a philosophical sweep and scope , so that from being theories of evolution they develop into theories of the universe .sx I will first consider very briefly the nature of the evidence which has led to the gradual supersession of the view of evolution as a purely mechanical process , and , secondly , outline some contemporary views with regard to the nature of the universe as a whole , which have been chiefly inspired by biology .sx I .sx CRITICISMS OF MECHANISM IN BIOLOGY .sx Characteristic Behaviour of Living Organisms .sx `Though the physico-chemical , or mechanistic conception of life is still very much alive in the minds of popular writers , I think it is now far from being so among serious students of biology .sx ' This statement appears at the beginning of professor J. S. Haldane's series of Donnellan lectures delivered in the University of Dublin in the spring of 1930 .sx He proceeds to cite as one of the grounds for this assertion the fact that `from the standpoint of the physical sciences the maintenance and reproduction of a living organism is nothing less than a standing miracle , and for the reason that coordinated .sx maintenance of structure and activity is inconsistent with the physical conception of self-existent matter and energy' .sx Two rather different conceptions are emphasised in the succeeding lectures .sx In the first place , living organisms exhibit what can only be represented as an inner drive to reach their appropriate form and structure , and , when it is reached , to maintain it .sx In the second , they .sx exhibit a similar drive to reach and maintain the environment appropriate to their proper functioning .sx An obvious illustration of the first conception is the behaviour of a crab who , when its Ieg is knocked off , proceeds to grow another .sx Inventors have yet to fashion a machine which will spontaneously replace a lost or damaged part with a new one .sx A more striking example is afforded by the experiments of the German biologist Driesch .sx In Driesch's experiments an embryo which has reached the stage in which it is a hollow sphere of undifferentiated cells without top or bottom , right or left , was divided into two or more sections by sharp cuts .sx Driesch found that each section developed into a complete embryo .sx Since the cuts might have been made along an almost infinite number of planes , any one part of the embryo must , it would seem , be prepared to assume any function and to develop any characteristics ; it must also be credited with an unconscious knowledge of how the other parts are developing .sx Thus any one cell can become a liver cell , a blood corpuscle , or a piece of bone tissue , according to the needs of the organism as a whole .sx `A very strange sort of machine , indeed' , says Driesch , `which is the same in all its parts' .sx `It is not possible' , he continues , `to conceive of a machine being divided in any direction and still remaining a machine .sx ' Driesch was led to the conclusion that there is a spontaneous tendency or drive in the organism to reach its appropriate form-structure and perform its appropriate function , in spite of interference , provided that the interference is not too great .sx The suggestion follows that it is only by considering the organism as a unity , a unity which can be regarded as the vehicle of this drive or force , even , it may be , of something analogous to an intention , that facts of this kind can be interpreted .sx Quest of appropriate environment .sx As an example of the second conception , the drive to achieve and to maintain the environment appropriate to the creature's activities , take the case of the salmon proceeding up stream , leaping obstacles and breasting the current in order to deposit her spawn in a particular environment .sx To suggest that the salmon is the vehicle of an unconscious purpose to reach this appropriate environment , a purpose which impels it to go on acting in a particular way until it succeeds , since it is to postulate more than can be observed , is also to postulate more than can be proved and more than a materialist would be prepared to allow .sx Yet it is extraordinarily difficult to explain the salmon's behaviour on any other assumption .sx It acts exactly as if it were so impelled .sx Under the influence of what is apparently an unconscious purpose to reach and maintain the environments which are appropriate to them , organisms will alter not only their behaviour but their structure .sx Thus , if you take the hydroid plant antennularia and remove it from the flat surface to which it is accustomed to adhere , it will immediately begin to change its structure , proliferating long waving roots or fibres in the vain effort to find something to grip .sx So , too , with the hyacinth bulbs which are commonly placed in jars .sx There is , in other words , in these cases a definite attempt on the part of the organism to adapt itself , if necessary by altering its structure , to an abnormal environment .sx Examples could , of course , be multiplied indefinitely .sx Professor Haldane arrived at similar conclusions from an examination of the delicately adjusted responses of the living organism to variations in oxygen supply .sx The Active Response of the Living Organism .sx On the basis of these and similar considerations two .sx principles emerge , each of which is incompatible with strictly mechanist interpretation .sx ( i ) In the first place , the behaviour of an organism cannot in all cases be adequately interpreted in terms of response to the stimulus of the environment .sx It is in this respect that its difference from a machine is most manifest .sx The responses of machines to their environment are automatic .sx Wind the spring and the watch goes ; turn the handle and the engine starts .sx But the response of a living organism to a stimulus , if response it can be called , is active .sx In this activity of response biologists and psychologists have traditionally distinguished three phases .sx