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XIX; Natural Science and General Thought

Natural Science and General Thought

I have now completed my survey of the methods and implications of Natural Science as exhibited in its various departments. Necessarily incomplete as this survey has been I venture to hope that it may serve as a basis for the formation of an estimate of any bearings which Natural Science as a special domain of Thought may have upon our more general views of the world and especially upon the spiritual aspects of experience. In the earlier lectures of the course I stated and discussed in some detail the main conclusions relating to the true characteristics and the limitations of scope of Natural Science which I conceive to be borne out and illustrated in the course of the survey of special departments of Science which is made in the later lectures. It seems clear that the position of Natural Science in relation to the more general conceptions of existence which fall within the province of Philosophy and Religion will be largely affected by the nature of our conceptions of the basic characteristics of Natural Science and of its scope. The nature of any ontological assumptions which may be regarded as necessary for the existence of Natural Science as a systematic scheme of thought or which may be held to be implicit in that scheme will be of the highest importance in this regard. The view which I have maintained and illustrated that the life of Natural Science consists essentially when it is rightly understood of an organized attempt or rather a series of efforts continued through the centuries to provide conceptual representations of our physical percepts will if it be accepted have a marked effect upon the external relations of this department of thought. This view tends to limit and circumscribe the influence which Natural Science will have upon the wider views of the world with which Philosophy and Religion concern themselves. If it be admitted that Natural Science when reduced to its essential elements is independent of any opinions which may be held as regards a reality behind phenomena and if the notions of final causes and of efficiency be regarded as extraneous to it it would seem to follow that the existence and the special results of Natural Science cannot be employed in any very direct manner for the purpose of throwing light upon the nature of an assumed reality or of exercising any decisive influence in the contest between rival views as to the nature of reality.

By adopting phenomenalism as a methodological assumption independently of any dogmatic assumption that it represents an ultimate philosophical view of existence on its physical side Natural Science cuts itself off from the possibility of providing criteria which shall be logically effective in relation to metaphysical theories of the nature of the “real” or of “existence.” This question of the character of any assumptions about reality which Natural Science may be thought to need is of practical importance because the fact that Natural Science has achieved successes of a kind and degree which cannot be ignored will lead to a presumption of irresistible weight for many minds in favour of any existential proposition which Natural Science can show to be really necessary as a foundation for the structure which it has reared. Such existential propositions if accepted on the authority of Natural Science and apparently evidenced by its successes would have a far-reaching and vital effect upon all conceptions philosophical or religious of the nature of reality. As an illustration we may take the influence outside Science itself of physical realism frequently supposed to be a necessary assumption for Natural Science.
In one of my earlier lectures I have emphasized the advantages which accrue to Natural Science by taking up a position of complete independence in relation to Philosophical theories as to the origin of the perceptual complex with which Natural Science has to do. These advantages entail the restriction that Natural Science cannot exercise so important an influence in relation to our general attitude towards the world as has sometimes been assigned to it especially by those who have attempted so to extend its scope that it was developed into a complete and dominant World Philosophy. If the view of the character and scope of Natural Science which I have maintained be correct Natural Science is circumscribed in its aim and restricted by its method. No doubt the majority of men of Science in all ages have believed that their aim was to penetrate to what they regarded as the reality behind phenomena and that successful scientific investigations might be expected to give them some detailed information as to the inner relations within that reality. Certainly many and probably most men of Science in recent times have been dominated by the conception known as physical realism in accordance with which the material world not only comes under the category of the real but is articulated in a manner corresponding closely to the distinctions and constructions which the mind makes by abstraction and idealization in the process of analysing and symbolizing its physical percepts. However the reflections of many of those who have studied the general characteristics of scientific procedure and theories some of them active investigators in some special department of Science have led them to the conviction that the adoption of physical realism is an otiose opinion which whatever its merits as a philosophical theory may be is essentially unnecessary as a presupposition of scientific method. I think there is evidence that this emancipatory movement is gaining ground and is likely in the future to progress much further in the minds of those who find leisure to devote some thought to the underlying assumptions and implications relating to the methodology of Natural Science.
We possess other kinds of knowledge besides that with which Natural Science is prima facie alone concerned. There exists a body of conceptual knowledge of the mode of working of the human mind represented by the results of Psychology and Logic. One of the functions of Psychology is to investigate the process of perception and to trace out the relations between perception and conception the bare recognition of which elements in separation due to abstraction is sufficient for the purposes of Natural Science which does not utilize the light thrown by Psychology upon their relations within the fundamental unity of the mind. Psychological investigations appear to fall into two distinct departments. On the one hand the subject is a purely psychical science in which the various functions and processes in the mind are analysed and the relations between them investigated. In the other branch on the border line between Mental Science and Physiology the functions of the mind are studied by means of their physical manifestations subject to assumptions as to the correlation of psychical and physical events and processes. On this latter side Psychology must be regarded as a mixed Science in the sense in which for the sake of distinction I have already employed the term. Pure logic the study of the formal side of thought may be regarded as closely connected with the more abstract side of Psychology. By analogy Logic may be described as the Grammar of Thought.
Such a Science as Sociology in its various departments including Anthropology Politics and Economics may be regarded as a mixed Science depending as these departments do upon investigations and classifications which involve both physical and psychical categories. Psychology and the Sciences of the sociological group have one point in common with Natural Science. They are all concerned not with the individual as such but with classes of individuals. To all of them the individual is of concern only so far as it is a member of some more or less extensive class; and only those features of the individual which it has in common with all the members of such a class are relevant to these branches of knowledge. This transcendence of the purely individual is characteristic of all knowledge which in the widest sense of the term can be designated as scientific knowledge. Of an individual object taking the term object in a wide sense we may have knowledge which when sufficiently extensive always differentiates that object from all others and may be considered collectively as knowledge of the history of that individual object. The history of a particular object including its present characteristics is unique so far as elements in that history are not referred to a system of classification in which the individual is for a specific purpose merged in a class. That history is never identical in all respects with the history of any other object. So far as the individual object is unique our knowledge of it fails to be subsumed under scientific knowledge in however general a sense we understand that term; it remains as historical not as scientific knowledge. That element in the genesis of an object or complex in its relations during its existence with its environment and in its past and present states which eludes all scientific classification and subsumption under scientific laws and theories may vary enormously in importance and amount in different cases. No two stones are ever found upon close examination to be absolutely indistinguishable from one another in respect of shape size and structure. The stories of the past bufferings of the two stones if it were possible or worth while to obtain knowledge of them would be full of details unlike in the two cases; this divergence being held to account for their present dissimilarities. The scientific interest in the stones is usually confined to an interest in the heap to which they belong the individuals being regarded only as samples of that heap; and their irresoluble individual differences are for scientific purposes neglected unless some specially distinctive features are observed in them which may give rise to some additional scientific inquiry.
When we turn to the case of living organisms and especially to the case of a particular man as an historical being the same considerations hold good with greatly increased force and import. At each juncture in the life of a man physical and psychical Science can be applied to give some partial accounts of the physiological processes in his body and nervous system of his reactions to external stimuli and of the psychical processes in his mind which are related to the determinations of his will; but these accounts are never complete in all details and they cannot be welded together into a single coherent whole. Not only his past history but also the individual peculiarities which distinguish him from every other being of his kind have some greater or less significance at every juncture of his life. Neither his history nor his character are identical with those of any other being. I have emphasized this fact of the ubiquity of the element of individuality in the perceptual world because it is one of which the bias of the man of Science who for his special purpose does not and cannot concern himself with the purely individual except so far as it is assumed to be an instance of the general tends to minimize the importance in relation to a general view of the world. For the struggles of the man of Science are in the direction of a constant attempt to diminish the importance of the purely individual element by showing that it is but an instance of the general and it is in doing this that his successes consist. There remains however in the world the irresoluble element of individuality of the complete removal of which there is no prospect. The principle of order in the world requires to be supplemented if not limited by the principle of individuality. The fact that the history and characteristics of a human being are unique does not however make it impossible for other persons to have a knowledge of that individual sufficient for the purpose of predicting with some greater or less degree of assurance and precision what the actions of that individual will be in given circumstances. This implies the assumption that the determinations of his will are not so wholly irregular and incalculable but that his conduct in a given situation is predictable in some considerable degree. In other words it is possible to have a knowledge of his character based upon knowledge of his past history and subject to the assumption that his character has a functional relation with the elements of his past behaviour. The difficult questions how far what is called self-determination goes and whether indeed it is an ultimately valid conception including the question of the validity of what is known as psychological determinism lie quite outside the scope of these lectures and accordingly cannot be here discussed. The kind of knowledge that we may have of a particular man is essentially knowledge of an individual not of a class although a very considerable part of it has no doubt reference to our knowledge of classes to which the individual belongs and so far is equivalent in kind to scientific knowledge.
Science has however made much use in quite recent times of one method of eliminating the effects of what I have called the principle of individuality. That method is the statistical by means of which valuable scientific knowledge may be obtained as to the behaviour of groups of individuals; it consists of a process of elimination of the effects of the purely individual characteristics of the individuals of which the groups are composed. By this method upon the basis of measured facts of observation relating to a large group of individuals tabulated in numerical form it is possible to correlate the behaviour of the members of the group with certain kinds of motives not necessarily conscious relating to that behaviour in such wise that by statistical analysis a knowledge can be obtained of the average effect of the motive upon the members of the group. I have used the term “motive” in a very general sense to denote any circumstance or set of circumstances which can be correlated with a particular kind of behaviour. Sometimes the statistical method has been applied to detect the existence of such correlation without previous assumption that a particular set of circumstances was a relevant motive. This method is of special value in the case of a motive of which the intensity is variable; it may then be shown by statistical analysis that the average behaviour of the particular kind of the members of a group has a functional relationship with the intensity of the motive. By this method a considerable amount of knowledge may be obtained of how a large group of individuals will behave in certain circumstances and especially as to the variability of behaviour when those circumstances change in a known manner. If for example it has been shown that there is in a given community and for a considerable period a correlation between the number of marriages in a year and the average price of corn in that year a definite piece of information has been obtained depending for its establishment upon a process of elimination of most of the many individual characteristics of members of the community which in any single instance will be factors in deciding for or against marriage. The effect of all other motives has been eliminated in the statement of the fact of correlation between the number of marriages and the one particular kind of circumstance the price of corn. A large amount of knowledge of partial correlations obtained by this method may afford scientific information about the average behaviour of the members of a community; and this knowledge may have value as a means of forecasting the future. But its value as enabling us to predict the behaviour of a particular individual in assigned circumstances is evanescent because no particular person is the average individual; neither has he in all respects a close resemblance to the average. For predictions of any value as to the behaviour of a particular person recourse must be had to the purely individual knowledge of those who have sufficient acquaintance with his past history and his present character and circumstances to enable them to form an estimate; and such individual knowledge is not in the main scientific knowledge.
Both scientific knowledge and the individual knowledge of which I have spoken have in common the fact that they are of the discursive kind obtained by an analysis and subsequent synthesis of particular elements. The two are distinguished from one another by the large divergence in the degrees of systematization which they involve; the former is obtained by systematic schematization; the latter by a process of unsystematic synthesis although it may contain elements in which systematic schematization is not entirely absent. Both these kinds of knowledge are abstract in very different degrees. But besides these kinds of knowledge there exists a kind of apprehension which is more immediate and direct although it is often inextricably combined with knowledge of the other kinds. This is knowledge as given by direct intuition in which the object in the subject-object relation is apparently apprehended all at once as a whole and not by a conscious synthesis of its parts and their relations. This intuitive knowledge of which the highest example is to be found in the apprehension in some moments of the artist or of the mystic is transitory and fleeting; for a process of analysis into parts and relations and resolution into discursive knowledge is incipient in it. In its purity it is incommunicable; as soon as an attempt is made to describe it in language the stage of abstraction has already been reached and the description fails to represent with absolute completeness the unique individuality of the whole as given by the original intuitive apprehension. In the individual who has been the subject in the intuition the impression of the whole as grasped at once intuitively may remain more or less vividly in the memory after the inevitable process of dissection has commenced but only that process gives him the power to communicate what he has experienced to others and in the act of communication the object as a unique indivisible whole becomes merged in systems of classification in which those aspects of it which constitute its uniqueness are largely lost. An exceptional power of obtaining an intuitional grasp of a complex as a whole is an essential element in the mental outfit of a man of Science of the highest order. Such intuitional and imaginative apprehension precedes and conditions any striking success in the process of discovery of the inner relations within the complex.
That element of human experience and life which may be summed up in the word cognition includes common knowledge which becomes in its developed form scientific knowledge and also what I have spoken of as individual knowledge and immediate or intuitional knowledge. But when we have taken all these not completely separable kinds of knowledge into account we have still to remember the fact that cognition however generally the term is understood is but one among other elements which make up the whole of human experience and life. It would not be necessary for my purpose to give a rigorous analysis of the elements of human experience such as might satisfy the psychologist or philosopher even if I were competent to attempt such a task. It is sufficient to refer to the elements of feeling and desire which include the fundamental springs of will and activity. These take explicit form in the apprehension of values spiritual moral intellectual aesthetic and material. In actual experience these elements with the cognitive element enter as components separable from one another only by abstraction; the fundamental unity of the stream of experience is such that it is not merely a sum of such elements. The qualitative difference between various kinds of experience may be to some extent represented by differences as regards prominence or intensity in these abstractly separable elements.
The main characteristics of the great departments of thought and activity Religion Philosophy Science and Art rest upon distinctions in the emphasis which they place in their aims and procedure upon the various elements of mental experience to which I have alluded. It may be said that the interests of Philosophy and of Pure Science are cognitive or as is often said intellectual; that the object of Philosophy is to obtain systematic knowledge and understanding of experience as a whole and that the object of Science is to represent certain kinds of experience conceptually. It may also be said that the interests of Religion and of Art are in the main connected with values spiritual and moral values in the one case and aesthetic values in the other. But such statements however correct they may be if they are understood as applying to ultimate aims and results cannot be applied without qualification to the processes and activities by means of which the aims are realized and the results obtained. That the aims of Philosophy and of Science are to attain to truth independently of the specific character of the valuations of that truth when obtained is doubtless correct; their direct concern is with cognition and not with valuation. But for a Philosopher or a man of Science truth is itself a value of the highest kind even if the truth contain unpleasant features; a recognition of its immediate ideal value or in some cases of its mediate value as a means for the attainment of practical ends is an essential spring of action in the mind of the genuine Philosopher or man of Science. The sustained emotion which we call the love of truth as a value is essential to the pursuit of Philosophical and of Scientific knowledge. At every stage in the age-long struggle to reach philosophical or scientific truth the combatants have been animated and sustained by a consciousness of the value of their goal. It is however true that the feeling for values or rather for specific values is one which has to be kept in severe restraint by the investigator in subordination to the cognitive side of his mind for otherwise it may distort his vision in a manner which may be very detrimental to the attainment of his aims.
That for the domains of religion and morality the apprehension of values is the fundamental factor can hardly be denied. In relation to religion this has been formulated by Höffding in the thesis that the fundamental axiom of religion is the conservation of values. But it must nevertheless be recognized that to found religion exclusively on the basis of feelings involving apprehension of specific values and their conservation and without any elements of cognition that is of knowledge actual or speculative is an impossibility. Conservation of values implies the existence of forms and modes in which they are conserved; and this fact necessarily brings values and their conservation into connection with conceptions of existence and reality. All valuations arise originally in close connection with ordinary experience of the physical and psychical world; and even in their most clarified form as they appear in the religious and moral consciousness they are dependent for their imagery their concrete expression and their concepts upon elements derived from that experience. Thus the domains of value and of existence are ultimately inseparable. All historical religions have been in close connection with the cognitive side of human experience and in some periods they have exercised an almost complete domination over that side. In the middle ages Religion represented the unity in which all conceptions not only of the spiritual world but also of the physical world were embraced; in which Art and in fact all forms of spiritual activity were contained and by which all their activities were regulated. All values and all conceptions of existence and reality were bound together in a unified system which only at the time of the Renaissance began to dissolve when Science Art and Philosophy set up claims to independence and development on their own lines unfettered by restrictions imposed upon them by the supposed necessities of the unified system in which they had previously been combined. The advent of this separation of different forms of spiritual life and activity led to the state of tension manifested in the contest lasting into our own time between the conceptions of Natural Science and those older conceptions of the physical world which were for a long time considered to be essentially connected with Religion. The complete cessation of this contest is dependent upon a full recognition of the validity of the claims both of Religion and of Science to independent life and activity each in its own sphere; and this requires as its condition a more precise formulation of the boundaries of their respective spheres than had formerly been made.
A somewhat similar remark may be made as regards the relations between Religion and Philosophy but as I venture to think the difficulties in this case are essentially greater than in the case of the relations between Religion and Natural Science. Philosophy and Religion are both of them in different senses concerned with the whole of human experience. The interests of Philosophy are mainly intellectual being concerned with the cognitive side of experience; those of Religion are more concerned with the practical side of experience with the spiritual needs of man with his hopes and fears his moral values and his emotional attitude towards existence. Philosophy in its eclectic view of human experience does not and cannot leave out of account the nature and specific character of values and especially of that species of values which we call moral; and here it has a specially close plane of contact with Religion. The fact to which I have already alluded that Religion which is primarily concerned with values cannot wholly divorce itself from conceptions of existents in which those values are realized brings it also in this regard into close contact with Philosophical Thought. In point of fact Religion has at all times found itself impelled at all events in the minds of more cultivated persons to ally itself with some form of Philosophy in which it might find the existential elements which might warrant an ascription of objectivity and of permanence to the carriers of its primary elements of value. The difficulty of combining religious conceptions with a coherent Philosophical scheme has been increased by the historical fact to which Professor Sorley has recently drawn attention in an emphatic manner that in the development of Philosophical systems the cognitive side of experience has formed almost exclusively the material out of which the systems have been built up; these systems have then been under the necessity of adapting themselves ex post facto to include that element of experience which we call the apprehension of values. Although it has been recognized at least in some quarters that Religion does not supply a World-Philosophy and that it should not be expected to fulfil that function and further that it is not in essence bound up with any philosophical theory of the nature of existence it remains nevertheless true that in so far as Religion seeks to relate its concepts of spiritual value with existential forms in which those values are realized it is impossible to treat Religion as completely independent of philosophical implications. Nearly all actual forms of Religion have been theistic whether monotheistic or polytheistic and even Buddhism which in its esoteric form is regarded as an exception is not solely a Religion but is also a most pronounced form of World-Philosophy. All forms of theism involve ideas differing widely in their nature mode of formulation and degree of precision which are concerned with the relations between God and the world. Thus the assertion of the existence of God does not simply and solely express a religious belief or an attitude of faith but takes also the form of a philosophical proposition or hypothesis of an ontological character. This brings with it a series of philosophical questions some of which at least are of so urgent a character not merely from a purely cognitive point of view but in relation to the needs of the religious consciousness that some answers to them more or less precise are an imperative necessity. This is so not merely or mainly on account of the inherent philosophical importance of these questions but because the whole character of Religion and its efficiency in providing for the primary spiritual needs which Religion is to satisfy are very fundamentally affected by the nature of the answers given to those questions.
Theism has been the fundamental basis of the most multifarious forms of Religion; and these have exhibited in different ages and in different countries and even among different groups of persons in one and the same age and country the most diverse ideas as to the conception of God and of the place which theism should fill in a general view of existence and life. In fact the particular kind of theism in a religious system is of most fundamental importance in relation to the actual functioning of the creed as an expression of the spiritual character of its adherents and as influencing all their activities. There exist and have always existed many persons who whilst dominated in their innermost being by theistic belief do not feel any need for the kind of support which may be afforded to their belief by philosophical conceptions. Many others whilst employing such conceptions as an adjunct to their belief do not feel the need of evidential support of their faith from the side of reasoned Philosophy. To such persons their theistic belief appears to them in the form of direct intuitive knowledge obtained in the course of actual experience and having the character of a certainty which can dispense with any proofs of the sort which reasoned Philosophy can be expected to furnish. Such persons may employ some kind of philosophical or rational scheme more or less consciously as a kind of framework into which their faith resting as it does on intuitive knowledge may be fitted. This framework is usually supplied by the traditional conceptions of the society in which they live or of the particular group in which they have been educated or by which they have been most effectively influenced. The most highly developed form of this attitude of mind towards theistic belief is to be found amongst the mystics of all periods many of whom may be regarded as specialists in relation to religious experience of the directly intuitional kind. The accounts of this kind of experience given in such a work as William James' Varieties of Religions Experience are of extreme interest. It is there shown that mystical phenomena are to be found amongst the adherents of the most diverse creeds and yet present in all such cases an essential similarity of general character. The accounts given of experiences of this order by those who have been their subjects take forms which are coloured in a high degree by their preconceived views; and this appears to indicate the presence of a large element of subjectivity in the interpretation of the actual experience. It is accordingly difficult to assess highly the value of such experience as evidence of the truth of any special cognitive views which may be held by persons who have such experience and who interpret it in terms of their personal and traditional beliefs. It seems clear that all attempts that may be made to base theistic or more general religious belief upon intuitional knowledge obtained directly in actual experience either of the mystical order or of a more ordinary kind will ultimately prove insufficient as a basis for such belief amongst a very large number and probably the majority of men. The history of religion shows that this is the case. Belief based upon direct intuition will for those who have it remain unaffected by discursive thought in relation to Philosophy and Science; and it is not for the sake of such persons that it is necessary to treat of the relations which theistic belief may have with philosophical or scientific views. For the more thoughtful members of the community these relations have in our time an inestimable importance; and the influence of the views formed of their specific character has an ultimate effect upon the attitude towards theistic belief of multitudes of men who do not consciously concern themselves with such relations on the more theoretical side. Accordingly the nature and extent of any influence which Natural Science exerts or ought to exert upon theistic belief both in its general and its more specific characters presents a problem the importance of which can hardly be overestimated in view of the effect which solutions of it may have directly upon the cognitive side and indirectly upon other sides of the religious consciousness.
Speaking broadly the main concern of Religion is with values and with existence as embodying values whilst Natural Science in its results has no concern with values. On the other hand Philosophy is concerned with cognition related both to values and to existence. It would then appear that the relation of Natural Science with Theism so far as such relation exists is in a sense indirect as it is through the mediation of Philosophy that it becomes effective. The influence which Natural Science may have upon Theism may be taken to depend first upon any assumptions of a metaphysical kind which may be held to be necessary for Natural Science to make for its own purposes; and secondly upon the amount and nature of the support which the existence and success of Natural Science may afford to particular theories of a philosophical or metaphysical character. As regards the influence of the first kind the acceptance of that view of the essential character of Natural Science which I have advocated and which view I have attempted to establish as correct leads I think to the inference that subject to one limiting condition of which I shall speak presently Natural Science taken by itself does not directly affect the theistic position either positively by providing support or negatively by giving rise to objections. In fact if no philosophical assumptions are made which lie outside the necessities of Natural Science the position of Natural Science in relation to theism as in relation to ontological theses generally is one of neutrality or independence. It is important to emphasize the fact that this position of independence only appertains to Natural Science when all conceptions not strictly necessary for its existence as a schematization of physical percepts are excluded. When Natural Science is taken in combination with metaphysical views which are in accordance with the opinion here adopted extraneous to it its position in relation to theistic or other ultimate ideas relating to the nature of reality becomes very different and its influence upon such conceptions may become of great importance.
It may perhaps seem to be the case that the position of independence here assigned to Natural Science is too absolute; that such a position of apparent isolation in the more general domain of thought and existence is untenable. It may be objected that the fact that it has been found possible to develop such a system as Natural Science which undoubtedly possesses a certain kind and amount of efficiency in relation to life and activity must lead to some inferences which show their effect in introducing limitations upon the characteristics of a general philosophy of the world and in particular upon any theistic or other mode in which ultimate reality is conceived. Such an objection would be valid were it not for one important limitation which the existence of Natural Science as we know and possess it places upon any theistic or other view of the world. Stated shortly that limitation consists in the fact that any acceptable view of the world whether theistic or other must be such as not to be incompatible with the existence of Natural Science. Any such general Philosophy must provide within itself a place which Natural Science may occupy as an autonomous system. The principle of order in physical phenomena with the limiting principle of individuality in these phenomena provide principles with which any Philosophy and any theistic view must not be incompatible if direct contest between Natural Science and Philosophical or Theistic thought is not to arise. Subject to completely adequate satisfaction of this condition Natural Science offers no obstacle to the free development of Theistic or other Philosophies on their own lines in the sense that no other purely logical consequences follow from the acceptance of Natural Science which are effective in the wider domains of Thought. I have already observed that any further influence which Natural Science may have upon general views of the world depends upon the nature of any ontological hypotheses or postulations which may be made in attempts to explore the nature of reality but which go beyond any assumptions which Natural Science itself needs.
Before discussing the nature of the bearings which Natural Science may have upon theories of reality and in particular upon theistic theories when it is supplemented by ontological postulations which go beyond its own special requirements I propose to make a few remarks upon what I take to be an essential characteristic of all Philosophical systems. Metaphysical Philosophy is not constructed upon a basis deduced by the canons of pure Logic from any set of axioms assumptions or presuppositions which are accepted by all human minds as possessing self-evidence or even definiteness of meaning. To the constructor of and to the adherents of a particular kind of Philosophy the assumptions and presuppositions of the system when indeed they are all explicitly recognized usually appear to possess apodictic certainty to be woven in the very web of the mind. To the adherents of a rival system and to critics in general these same assumptions or presuppositions may appear to lack this quality of self-evidence to be only probable in some degree or in no degree and often to be either meaningless or to have only a hazy and ill-defined meaning. In this region of thought what seems obvious and certain to some minds appears to be neither obvious nor true at least without much qualification to other minds at the same epoch or in a different age. If Philosophers were not only logic-machines working in accordance with a single logical canon but also in possession of a single universally accepted set of premisses or postulations to be employed in the logical processes the state of philosophical thought would be very different from what it actually is and always has been. We might then at least hope to attain to a Philosophy which would receive general assent from all those persons who made a sufficient amount of effort and were possessed of sufficient mental grasp to enable them to understand it; but this is very far from being the case. The presuppositions which commend themselves to different minds diverge in the widest manner from one another. These presuppositions which serve as premisses necessary before deductive logic can function depend upon the widely varying characteristics of particular minds and groups of minds. The causes which make a particular premiss appear to a particular mind or to a particular class of minds to have either irresistible cogency or at least a high degree of probability are not in their nature purely intellectual. They depend upon the education traditions and idiosyncrasies of such individuals or classes; upon irreducible peculiarities of particular minds. The reaction of the individual as an inseparable whole to his experience is involved in their selection. In this whole understanding feelings desires and tradition are only in abstraction separable from one another. It is the undifferentiated individuality that is really effective in determining the choice of the axioms and premisses which commend themselves to the individual as the fundamental elements in his Philosophy. The reasoning faculty we distinguish as a separate faculty by abstraction only; its function is coordinative and it is operative upon data which it does not and cannot alone originate.
When an explanation is offered of the fact that there has always existed a large degree of divergence between different philosophical views and creeds emphasis is often laid upon misunderstandings as to the terminology in which philosophical ideas are expressed. No doubt this factor is a real one in this connection; as language was originally developed chiefly to serve much more purely practical purposes than to provide the means of expressing subtle philosophical distinctions. The process of adaptation of language for the latter purpose is certainly far from complete and leaves ample scope for shades of variation in the precise meaning that can be attached to the terms employed; and this naturally leads to controversies in which these differences in the interpretation of language are far from negligible. Nevertheless the reason I have before given to account for the extreme divergences in philosophical opinions is I think more fundamental than what is due to the imperfect functioning of language. The particular axioms and postulations performing the function of premisses of a particular system of Philosophy are the true characteristics of that system; they form the essential element which distinguishes it from rival views. It is in differences of these characteristic premisses that the everlasting divergence of philosophical views which flourish in the same age or have been prevalent in different ages is to be found.
An important consequence of the a-logical character of such a premiss that is of the fact that it is not a purely logical deduction from other premisses of which the validity is admitted by all normal minds is that an absolute denial of its truth cannot be refuted by any process of reasoning which rests upon a basis recognized by all men or even by all Philosophers. Every such presupposition rests in reality upon a judgment of probability ranging from faith of various degrees up to moral certainty. Some presuppositions of this class are of such a character that they do actually receive the assent of all or nearly all men. An example of this is the belief in the existence of other selves besides our own selves. If however a person chooses to take up the position of a solipsist it would appear that his view cannot be refuted by any process which would show that his opinion leads to logical contradiction. His view appears to us however absurd and almost insane because we all have an irresistible belief that seems to us consonant with our whole experience that his view is wrong. Although I have described scientific knowledge as essentially public knowledge it is not necessarily absolutely impossible for a solipsist if there be such a person to set up an account of the world regarded exclusively as a series of psychical happenings in his own consciousness. As regards other ontological hypotheses there is no such practical unanimity of opinion as in the case of the hypothesis of the existence of other persons with a psychical being resembling our own; and this lack of unanimity exhibits itself in the presence of all the manifold realistic and idealistic species of Philosophy with which the history of Philosophy is conversant.
I have emphasized the fact that the influence of Natural Science upon our general views of the world depends upon the nature of ontological postulations which go beyond any assumptions which Natural Science needs for its own purposes. The complex of physical percepts taken as an appearance into the ground of which Natural Science does not need to inquire cannot be regarded simply as a product of the individual mind although the activities of the individual are clearly a factor in determining physical presentations. As the fact of the existence of Science as public knowledge testifies the physical complex contains a large element which appears to be independent of any particular percipient and in this the objectivity of the physical world for collective mankind consists. For individual minds this given element can only be taken as a datum which is accepted in perception. The relations between sensations and perception form a domain which the psychologist seeks to describe conceptually but he like the worker in Natural Science accepts as a datum the fact that we have a stream of sensations which we do not appear to originate. The fact that there is in the complex of percepts an element independent of any individual mind of a character consistent with its description and symbolization by rational schemes to an extent of which we do not know the limits is the fundamental fact which emerges from the results and history of Natural Science. Scientific laws and theories are the product or creation of mental activity but are dependent for the raw material from which they are constructed upon given characteristics of the perceptual complex. These characteristics are not free creations of the mind but data without which Science could not even begin to exist. Thus Natural Science exists only in virtue of the fact that the physical domain the perceptual complex is of such a character as to render possible to the extent which we find by experience is actually the case its conceptual representation by laws and schemes.
When a metaphysical theory or hypothesis is set up as to the fundamental character of this element of the physical complex that is apparently not dependent on the individual mind; that is when some ontological assumption is made having reference to it there is then provided a bridge by means of which Natural Science is connected with general Philosophy. The precise nature of such an ontological assumption varies widely in different species of metaphysical Philosophy. All forms of realistic Philosophy agree in making the assumption that the element in the physical domain which appears to be independent of the individual mind has a real and independent existence which does not wholly depend upon its being a co-factor in the subject-object relation. The assumption is that there exists a real complex which is not as it were exhausted in the subject-object relation but can be separated out of that relation not merely in abstraction so that it has an existence independent of that relation. Different forms of realism vary widely in the conceptions they adopt as to the nature of that reality. In some forms of realism this element is taken to be psychical in its nature and thus in some degree akin to the human mind; and some systems of thought assume it to consist of a multitude of psychical individuals or monads. The realism of common sense conceives this element as materialistic and articulated in the same way as it appears to be in our perceptions although a distinction between primary and secondary qualities of material objects receives some recognition; the independent real element being more closely related with the former. The ordinary realism of Science physical realism regards the real complex as articulated in accordance with the distinctions introduced by scientific theories and of a non-psychical character; atoms electrons etc. are regarded as real. Neither scientific realism nor that of common sense is necessarily materialistic in the sense of assuming the psychical to be reducible to or entirely subordinate to the non-psychical although as we have seen this assumption has been made by various influential exponents of Natural Science. Some forms of realism have been agnostic in the sense that although they have recognized the existence of this real element in the world they have regarded any precise characterization of it as outside the domain of possible knowledge. All forms of what may be called critical realism to distinguish it both from physical realism and naive realism assume the existence of a reality which in some sense manifests itself in our sense-perceptions. But critical realism refrains from identifying the real with any of the conceptual constructions of Natural Science. In particular Monadism refuses to identify Monads with atoms or electrons or biophors. Idealism even when it does not stop short at purely subjective idealism does not take the step of separating the object out of the subject-object relation and regarding it as existing independent of that relation. Whilst holding fast to that relation without which it regards objectivity as meaningless it usually regards the postulation of a Universal Mind for which the world is a realm of objectivity as essential for a Philosophy which shall suffice to give any adequate account of human experience.
In the next lecture I propose to discuss the bearings which Natural Science may have upon the Philosophy of Theism when some ontological hypothesis is made which will suffice to establish the nexus of which I have spoken with an outlook on existence wider than that which Natural Science need adopt for its own special purpose. Such a discussion can naturally deal with but a small part of the whole subject of Theism but it is concerned with an aspect of the problem of Religion which is of great importance in relation to contemporary thought on the subject.