Spencer's Philosophy of Science Part 1

Spencer's Philosophy of Science.

by C. Lloyd Morgan.

SPENCER'S PHILOSOPHY OF SCIENCE

Towards the close of 1870, while I was still in my teens, my youthful enthusiasm was fired by reading Tyndall's Discourse on _The Scientific Use of the Imagination_. The vision of the conquest of nature by physical science--a vision which had but lately begun to open up to my wondering gaze--was rendered clearer and more extensive. Of the theory of evolution I knew but little; but I none the less felt a.s.sured that it had come to stay and to prevail. Was it not accepted by all of _us_--the enlightened and emanc.i.p.ated men of science whose ranks I had joined as a raw recruit? Believing that I was independently breaking free of all authority, to the authority that appealed to my fancy, and to a new loyalty, I was a willing slave. And here in one glowing sentence the inner core of evolution lay revealed.

'Strip it naked and you stand face to face with the notion that not alone the more ign.o.ble forms of animalcular and animal life, not alone the n.o.bler forms of the horse and the lion, not alone the exquisite and wonderful mechanism of the human body, but that the human mind itself--emotion, intellect and all their phenomena--were once latent in a fiery cloud.'[1]

With sparkling eyes I quoted these brave words to a friend of my father's, whose comments were often as caustic as his sympathy in my interests was kindly. With a grave smile he asked whether the notion was not perhaps stripped too naked to preserve the decencies of modest thought; he inquired whether I had not learnt from _Sartor Resartus_ that the philosophy of nature is a Philosophy of Clothes; and he bade me devote a little time to quiet and careful consideration of what Tyndall really meant--meant in terms of the exact science he professed--by the phrase 'latent in a fiery cloud'. I dimly suspected that the old gentleman--old in the sense of being my father's contemporary--was ignorant of those recent developments of modern science with which I had been acquainted for weeks, nay more for months. Perhaps he had never even heard of the nebular hypothesis! But I felt that I had done him an injustice when, next morning, he sent round a volume of the _Westminster Review_ with a slip of paper indicating an article on 'Progress: its Law and Cause'.

Such was my introduction to Herbert Spencer, some of whose works I read with admiration during the next few years.

I have no very distinct recollection of the impression produced on my mind by the germinal essay of 1857, save that it served to quicken that craving, which is, I suppose, characteristic of those who have some natural bent towards philosophy--the imperative craving to seek and, if it may be, to find the one in the many. In any case Tyndall's suggestive sentence was here amplified and the underlying law was disclosed.

'Whether it be in the development of the Earth, in the development of Life upon its surface, in the development of Society, of Government, of Manufacture, of Commerce, of Language, Literature, Science, Art, the same evolution of the simple into the complex, through successive differentiations, holds throughout. From the earliest traceable cosmical changes down to the latest results of civilisation, we shall find that the transformation of the h.o.m.ogeneous into the heterogeneous, is that in which Progress essentially consists.'[2]

Here was just what I wanted--on the one hand the whole wide universe of existence; and on the other hand a brief formula with which to label its potted essence. How breathlessly one was led on, with only such breaches of continuity as separate paragraphs inevitably impose, right away from the primitive fire-mist to one of Bach's fugues or the critical doctrines of Mr. Ruskin, guided throughout by the magic of differentiation. What if the modes of existence, dealt with in successive sections, were somewhat startlingly diverse! Was not this itself a supreme example of the evolution of that diversity which the formula enables us to interpret? For if there were a pa.s.sage from the h.o.m.ogeneous to the heterogeneous, the more heterogeneous the products--inorganic, organic, and superorganic, as I learnt to call them--the stronger the evidence for the law. Only by shutting one's eyes to the light that had been shed on the world by evolution could one fail to see how simple and yet how inevitable was the whole business.

If then differentiation be the cardinal law of evolution--for the correlative concept of integration receives no emphasis in this early essay--does not the universality of the law imply a universal cause?

Just as gravitation was a.s.signable as a _cause_ of each of the groups of phenomena which Kepler formulated; so might some equally simple attribute of things be a.s.signable as the cause of each of the groups of phenomena formulated in terms of differentiation. Now the only obvious respect in which all kinds of Progress are alike, is, that they are modes of change; and hence in some characteristic of changes in general, the desired solution must be found. Thus we are led up to the statement of the all-pervading principle which determines the all-pervading process of differentiation. It is this: _Every active force produces more than one change--every cause produces more than one effect._[3]

In the first part of the Essay many and varied facts are adduced to show that every kind of progress is from the simple to the complex. The aim of the second part is to show why this is so: it is 'because each change is followed by many changes'. From the beginning, the decomposition of every expended force into several forces has been perpetually producing a higher complication, and thus Progress is not an accident but a beneficent necessity. In a brief third part we are bidden to remember that

'after all that has been said the ultimate mystery remains just as it was. The explanation of that which is explicable does but bring out into greater clearness the inexplicableness of that which remains behind.... The sincere man of science, content to follow wherever the evidence leads him becomes by each new enquiry more profoundly convinced that the Universe is an insoluble problem....

In all directions his investigations bring him face to face with the unknowable; and he ever more clearly perceives it to be the unknowable'.[4]

There is I think a growing consensus of opinion that the first of these three parts, subsequently expanded and ill.u.s.trated with astonis.h.i.+ng wealth of detail in the volumes of the _Synthetic Philosophy_, contains the germ of all that is best in the teaching of Herbert Spencer; and that it was amid phenomena which admitted of interpretation from the biological, or quasi-biological, point of view that he found his most congenial sphere of work and the one in which his method was most effectively employed. The story of evolution is the story of inter-related changes. In any organic whole there are certain salient features of the historical sequence.[5] The parts get more different from each other, and they also get more effectively connected with each other; the individual whole gets more different from its environment, and it also preserves and extends its connexion with the environment; the several individuals get more different from others, while their connexion with others is retained and new connexions are established. Nowadays these central ideas may seem familiar enough; but that is just because Spencer's thought has been so completely a.s.similated. And then we must remember that these main principles are supplemented by a great number of ancillary generalizations, many of which have been incorporated in the scientific doctrine which is current to-day. We must bear in mind that of the _Biology_ Charles Darwin wrote:[6] 'I am astonished at its prodigality of original thought.' Of the _Psychology_ William James says[7] that of the systematic treatises it will rank as the most original. These are the opinions of experts. No discussion of sociology or ethics is complete if it ignores Spencer's contributions to these subjects. The _Ethics_, says James[8] is a most vital and original piece of att.i.tude-taking in the world of ideals. It was his firm and often inflexible 'att.i.tude' which was a source of strength in Spencer, though it was the strength of rigidity rather than that of sinewy suppleness. This was part of a certain 'narrowness of intent and vastness of extent' which characterized his mental vision. He was so obsessed with the paramount importance of biological relations.h.i.+ps that in his _Sociology_, his _Ethics_, his _Psychology_, he failed to do justice to, or even to realize the presence of, other and higher relations.h.i.+ps--higher, that is, in the evolutionary scale.

But it was his signal merit to work biological interpretation for all, and perhaps more than, it was worth. It was on these lines that he was led to find a clue to those social and political developments, the discussion of which, in the _Nonconformist_ of 1842, const.i.tuted the first step from the life of an engineer to that other kind of life which led to the elaboration of the _Synthetic Philosophy_.[9] In his later years he was saddened to see that many of the social and political doctrines, for the establishment of which he had striven so strenuously, were not accepted by a newer generation of thinkers. Still, to have taken a definite and, for all his detractors may say, an honoured position in the line of those who make history in the philosophy of life and mind--that could never be taken away from him.

It will perhaps be said that this emphasis on the philosophy of life and mind does scant justice to the range and sweep of Spencer's philosophy as a whole; and no doubt others will contend that the emphasis should be laid elsewhere; on the mechanical foundations; on evolution as a universal principle. It will be urged that Spencer widened to men's view the scope of scientific explanation. He proclaimed 'the gradual growth of all things by natural processes out of natural antecedents'.[10] Even in the _Nonconformist_ letters 'there is', he himself says,[11] 'definitely expressed a belief in the universality of law--law in the realm of mind as in that of matter--law throughout the life of society as throughout the individual life. So, too, is it with the correlative idea of universal causation.' And if there be law it must at bottom be one law. Thus in _First Principles_ Spencer propounded a sweeping and sonorous formula, which every disciple knows by heart, embodying the fundamental traits of that unceasing redistribution of matter and motion which characterizes evolution as contrasted with dissolution. Was it not this that he himself regarded as his main contribution to philosophy? Did he not himself provide a summary, setting forth the sixteen articles of the Spencerian creed; and is not this summary given a prominent position in the Preface he wrote to Howard Collins's _Epitome of the Synthetic Philosophy_? Do not these fundamental articles of his faith deal with ubiquitous causes, with the instability of the h.o.m.ogeneous and the multiplication of effects, with segregation and equilibration, and with the basal conception of the persistence of force? There is here, it may be said, no special reference to the organic and the superorganic. And why? Just because Spencer's interpretation is all-inclusive; because biology, psychology, sociology, ethics are, broadly considered, concerned only with incidents of the later scenes of the great mechanical drama of evolution. Are we not again and again bidden, now in forecast, now in retrospect, to look below the surface, and constantly to bear in mind that the aim of philosophy, as completely unified knowledge, is 'the interpretation of all phenomena in terms of Matter, Motion, and Force'?[12] It is true that the affairs of the mind give pause and seem to present something of a difficulty. But even here 'specifically stated, the problem is to interpret mental evolution in terms of the redistribution of matter and motion'.[13] An adequate explanation of nervous evolution involves an adequate explanation of the concomitant evolution of mind. It is true that the ant.i.thesis of subject and object is never to be transcended 'while consciousness lasts'.[14] But if all existence, distinguishable as subjective, is resolvable into units of consciousness, which in their obverse or objective aspect are oscillations of molecules,[15] what more is required to round off the explanation of every thing, save the Unknowable--save the Ultimate Reality in which subject and object are united? In the end we are baffled by mystery; let us, therefore, make the best of it and rejoice.

'We can think of Matter only in terms of Mind. We can think of Mind only in terms of Matter. When we have pushed our explorations of the first to its uttermost limit we are referred to the second for a final answer; and when we have got the final answer to the second we are referred back to the first for an interpretation of it.'[14]

And so neither answer is final. Finality is only reached when both are swallowed up, not in victory, but in defeat. Shall we not then glory in defeat and sing its praises often?

I must leave to some future Herbert Spencer lecturer the discussion of his doctrine of the Unknowable and the critical consideration of its place and value in philosophy. I would fain leave it altogether on one side; but that is impossible. Although the _First Principles_ is divided into two Parts, dealing respectively with the Unknowable and the Knowable, we have not by any means done with the former when we turn from the First Part to the Second. With Spencer we have never done with the Unknowable, the Unconditioned Reality and the other aliases by which it goes. His persistence of force is the persistence of Unknowable Force. In a leading pa.s.sage, at any rate, it is avowedly 'the persistence of some Cause which transcends our knowledge and conception.

In a.s.serting it we a.s.sert an Unconditioned Reality without beginning or end'.[16] There must, he holds, be something at the back of the evolutionary drama which we study--something that is both a principle of activity and a permanent _nexus_.[17] The pity of it is that we know not, and can never know, what on earth (or in heaven!) it is. We only know that it exists, and somehow produces the whole show. Now it would much conduce to clearness of thought and of statement if we could agree to eliminate those terribly ambiguous words 'force' and 'cause' when we are dealing with the fundamental postulate (if such it be) that there must be something at the back of evolution to make it what it is; and the word Source seems ready to our hand and might well be given this special significance. But Spencer uses Agency, Power, Cause, Force, in this connexion. In how many senses he uses the word 'force' I am not prepared to say. It is often a synonym for cause; it stands alike for matter and energy;[18] it is the objective correlate of our subjective sense of effort.[19] There is a 'correlation and equivalence between external forces and the mental forces generated by them under the form of sensations'.[20] And when we pa.s.s to human life in society, whatever in any way facilitates or impedes social, political, or economic change, is spoken of in terms of force.[21] With an apparent vagueness and laxity almost unparalleled, force is used in wellnigh every conceivable sense of this ambiguous word--except, perhaps, that which is now sanctioned by definition in mathematical physics. I say apparent vagueness and laxity because, subtly underlying all this varied usage, is the unifying conception of Source as the ultimate basis of all enforcement. From this flows all necessity whether in things or thoughts or any combination of the two. Thus persistence of force is Spencer's favourite expression for uniform determinism at or near its Source.

Now, as I understand the position, science has nothing whatever to do with the Source or Sources of phenomena. By a wise self-denying ordinance it rules all questions of ultimate origin out of court. It regards them as beyond its special sphere of jurisdiction. It deals with phenomena in terms of connexion within an orderly scheme, and it does not profess to explain _why_ the connexions are such as they are found to be. In any discussion of this or that sequence of events which may fall under the wide and rather vague heading of evolution, it is just a consistent story of the events in their total relatedness that science endeavours to tell. The question: But what evolves the evolved? is for science (or should I say for those who accept this delimitation of the province of science?) not so much unanswerable in any terms, as unanswerable in scientific terms. For the terms in which an answer must be given are incommensurable with the concepts with which science has elected to carry on its business as interpreter of nature. To this question therefore the man of science, speaking for his order, simply replies: We do not know. Is this, then, Spencer's answer? Far from it.

The man of science here makes, or should make, no positive a.s.sertion, save in respect of the limits of his field of inquiry. If you beg him to tell you what that which he knows not is, or does, he regards such a question as meaningless. But Spencer's Unknowable, notwithstanding its negative prefix, is the Ultimate Reality, and does all that is in any way done. We may not know _what_ it is; but _that_ it is, is the most a.s.sured of all a.s.sured certainties. And when it comes to doing, what can be more dramatically positive than that which bears a name of negation?

Whatever it may not be, it is the Power that drives all the machinery in this workshop of a world; it is the Power which lies at the back of such wit as man has to interpret it, and, in some measure, to utilize its mechanism.

It seems plain enough that Spencer distinguishes, or seeks to distinguish, between those knowable effects which we call natural phenomena and their Unknowable Cause or Source. And this seems to be in line with the distinction which his critic, M. Bergson, draws between 'the evolved which is a result' and 'evolution itself, which is the act by which the result is obtained'.[22] An act implies an agent, and the agency of which the evolved is a manifestation is for M. Bergson Life, while for Spencer it is that very vigorous agency--the Unknowable. Now in criticizing Spencer, M. Bergson says:

'The usual device of the Spencerian method consists in reconstructing evolution with the fragments of the evolved.... It is not however by dividing the evolved that we shall reach the principle of that which evolves. It is not by recomposing the evolved with itself that we shall reproduce the evolution of which it is the term.'[23]

But does Spencer ever suggest that we shall thus reach the principle of that which evolves--by which, if I mistake not, M. Bergson means the Source of evolution? Does he not urge that we can neither reach it in this way, nor in any other way? For M. Bergson, as for Spencer, it is unknowable by the intellect--it can only be known by what M. Bergson calls intuition. For both thinkers, the intellect provides only a world of symbols; and Spencer's transfigured realism may be matched by what Dr. Wildon Carr calls M. Bergson's transformed realism.[24] So long as we are dealing with the evolved--which is that with which alone science attempts to deal--Spencer, M. Bergson, and the rest of us are in like case. We must stumble on intellectually with our symbols as best we may.

'Whether we posit the present structure of mind or the present subdivision of matter in either case we remain in the evolved: we are told nothing of what evolves, nothing of evolution.'[25] _Nothing of what evolves!_ Spencer might exclaim with a groan. Have I then written all those pages and pages on the Unknowable for nought? Is it not a fundamental tenet of my philosophy that there must be, and therefore is, a Source of the evolved--of the phenomenal world which is merely an expression in terms of intellectual symbolism, of that ultimate Power which, though its nature may baffle the intellect, is none the less the most real of all realities?

It would take us too far from the line of Spencer's thought to consider M. Bergson's doctrine that it is the intellect that portions the world into lots;[26] that cuts the facts out of the interpenetrating whole of reality, and renders them artificially distinct within the continuity of becoming. It suffices to note that on such a presupposition 'the cardinal error of Spencer is to take experience already allotted as given, whereas the true problem is to know how the allotment was worked'.[27] I am not prepared to give--indeed I have been unable to find--M. Bergson's own solution of the problem. I gather that it was Life itself that somehow allotted concepts and objects in such correspondence as should be practically useful though metaphysically false and illusory. But just how it was done I have still to learn. 'The original activity was', we are told, 'a simple thing which became diversified through the very construction of mechanisms such as those of the brain,'[28] which, as Life's tool, has facilitated the chopping up of a continuous interpenetrating reality into mince-meat for intellectual a.s.similation. Such a conception was foreign to Spencer's thought. But some of us may find it hard to distinguish M. Bergson's 'original activity' from Spencer's Unknowable, which, so far as one can make out, somehow produced precisely the same results. As a matter of fact, M. Bergson seems to put into Life, as Spencer put into the Unknowable, the potentiality of producing all that actually exists.

For Spencer, as for M. Bergson, we live in a world of change. But neither is content to accept changes as facts to be linked up within a scheme of scientific interpretation. Both must seek their Source. Now to inquire into the Source or Sources of phenomena is characteristic of man as thinker. And if, in common with those whom I follow, I regard this quest as beyond the limits of science, I am well aware that such delimitation of fields of inquiry is by no means universally accepted.

M. Bergson, for example, regards metaphysics as the _Science_[29] which claims to dispense with symbols, which turns its back on a.n.a.lysis, which eschews logic, which dispenses with relativity and pierces to the absolute, which, apparently, uses the intellect only to establish its utter incompetence in this department of 'science'. Merely saying that this, whatever else it may be, is not what I, for one, understand by science--and not, by the way, what M. Bergson in other pa.s.sages seems to mean by science[30]--I pa.s.s on to Spencer's treatment of the philosophy of science which, for him, is 'completely unified knowledge', 'the truths of philosophy bearing the same relation to the highest scientific truths that each of these bears to lower scientific truths.'

I suppose one of the basal truths in his philosophy of science is for Spencer the universality of connexion between cause and effect. Now let us eliminate Source as the Ultimate Cause (so far as that is possible in Spencer); let us restrict our attention to cause and effect in the realm of the knowable. When we try to do this we find his statements concerning them scarcely less puzzling than those that refer to force, with which cause is so often identified. Thus we are told[31] that 'motion set up in any direction is itself a cause of further motion in that direction since it is a manifestation of a surplus force in that direction'; and elsewhere[32] that 'the momentum of a body causes it to move in a straight line and at a uniform velocity'. A distinction is drawn between cause and conditions. But both produce effects, and only on these terms can there be that 'proportionality or equivalence between cause and effect' on which Spencer insists.[33] There is, however, scarcely a hint of what const.i.tutes the difference between cause and conditions, save in so far as he speaks[34] of 'those conspicuous antecedents which we call the causes' and 'those accompanying antecedents which we call the conditions'. Many of the details of his treatment I find most perplexing; but to recite examples would be wearisome. And then, in the ninth and tenth articles of the Spencerian creed, cause plays a somewhat different part. For, there, the instability of the h.o.m.ogeneous and the multiplication of effects are given as the chief causes which 'necessitate' that redistribution of matter and motion of which evolution is one phase. Similarly, as I have noted above, in 'Progress: its Law and Cause', the fundamental attribute of all modes of change--that every cause produces more than one effect--is itself spoken of as a cause, and likened to 'gravitation as the cause of each of the groups of phenomena which Kepler formulated'.

In these cases a generalization is regarded as the cause of the phenomena from which the generalization is drawn. But sometimes it is spoken of as the reason for the phenomena.[35] Here again, however, as throughout his work, reference to Source is close at hand. Hence, in place of the words cause and force, the word agency[36] sometimes stands for that which produces effects; or the word factor may be used. Thus we are told[37] of phenomena continually complicating under the influence of the same original factors'; and we meet with the argument (contra Huxley) that states of consciousness are factors, that is, they 'have the power of working changes in the nervous system and setting up motions'.[38] Always close at hand, constantly underlying Spencer's thought, is the notion of power which works changes. In his treatment of the philosophy of science we are never far from the noumenal Source of phenomena.

'For that interpretation of things which is alone possible for us this is all we require to know--that the force or energy manifested, now in one way now in another, persists or remains unchanged in amount. But when we ask what this energy is, there is no answer save that it is the noumenal Cause implied by the phenomenal effect.'[39]

Was it partly with Spencer in view that Mr. Bertrand Russell recently urged[40] that the word cause 'is so inextricably bound up with misleading a.s.sociations as to make its complete extrusion from the philosophical vocabulary desirable'? Professor Mach[41] had previously expressed the hope 'that the science of the future will discard the use of cause and effect as formally obscure'. And as long ago as 1870 W. K.

Clifford[42] tried to show in 'what sort of way an exact knowledge of the facts would supersede an enquiry after the causes of them'; and urged that the hypothesis of continuity 'involves such an interdependence of the facts of the universe as forbids us to speak of one fact or set of facts as the cause of another fact or set of facts'.

Such views may, perhaps, be regarded as extreme; and the word cause is not likely to be extruded from the vocabulary of current speech, of the less exact branches of science, or of general discussions of world-processes. Still, a philosophy of science must take note of this criticism of the use of a term which is, to say the least of it, ambiguous. We must at any rate try to get rid of ambiguity. Now we live in a world of what, in a very broad and inclusive sense, may be called things; and these things are in varied ways related to each other. (I must beg leave to a.s.sume, without discussion, that the relatedness of things is no less const.i.tutive of the world with which a philosophy of science has to deal than the things which are in relation.) And when things stand in certain kinds of relatedness to each other changes take place. The trouble is that the kinds of relatedness are so many and the kinds of change are also so many! Spencer tried to reduce all kinds of relatedness to one quasi-mechanical type; and he signally failed--or shall I say that he succeeded only by ignoring all the specific differences on the one hand, and, on the other hand, by so smudgy an extension of the meaning of mechanical and physical terms as to make them do duty in every conceivable connexion?

So long as we can deal with simple types of relatedness, such as that which we call gravitative, in any given system of things regarded as isolated, we can express in formulae not only the rate of change within the system, but also the rate at which the rate of change itself changes. And these formulae are found to be generally applicable where like things are in a like field of relatedness. So that Spencer's persistence of force (at least in one of its many meanings) is replaced in such cases by sameness of differential equations. And in such cases we have no need for the word cause. Of course the value of the constants in any such formula depends upon the nature of the field of relatedness and of the things therein; and only certain systems, in which the relations are simple, or are susceptible of simplification, can be dealt with, at present, in this manner. It is imperative to remember that not only the rate of change but the kind of change differs in different relational fields--a fact of which Spencer took too little cognizance, so bent was he on some sort of unification at all hazards. Revert now to a field of gravitative relatedness, in which the motion of things is the kind of change, while the rate of change is expressible in a formula; may we not say that the co-presence of things in this relations.h.i.+p does imply certain motions and changes of motion within the system to which the term gravitative applies? There seems little room for ambiguity if we call what is thus implied the effect, and if we term those modes of relatedness which carry this kind of implication, effective. It may, however, be said that it sounds somewhat strange to speak of relations as effective. How can mere relatedness as such _do_ anything? What is implied by the effect is surely, it will be urged, a cause in the full and rich sense of the word--a cause which produces the effect. For what is here suggested is nothing more than a generalized statement of the truth that the relational const.i.tution of the system being what it is, the changes are what they are! And so we come back to the conception of an agency which in some way produces the observable change--of a power which is active behind the phenomenal scene--of force and cause in the Spencerian sense. But, so far as scientific interpretation is concerned, this reference to Source--for such it really is--is useless. The gravitative system can be dealt with scientifically just as well without it as with it.

What, then, becomes of the scientific conception of energy? Is not energy that which produces observable change? Is it not active in the sense required? And can we say that this conception is useless for scientific interpretation? I suppose most of us, in our student days, have pa.s.sed through the phase of regarding energy as an active demon which plays a notorious part in the physical drama. Spencer loved it dearly. But some of us, under what we consider wiser guidance, hold that what we should understand by kinetic energy is nothing of this sort. It is a constant ratio of variables, conveniently expressed as 1/2_mv_^{2}.

That, however, it may be said, is absurd. Energy is not merely a ratio or a formula; it is something much more real; perhaps the most real of all the realities the being of which has been disclosed by physical science. Granted in a sense, and a very true sense. But what is this reality? It is the reality of the changes themselves in those fields of relatedness to which the formula has reference. There is nothing, I conceive, in the modern treatment of energy that affords any scientific justification of the Spencerian view[43] that energy is an agent through the activity of which the constant ratio of variables is maintained in the physical world.

I feel sure that it will still be said that change must inevitably imply that which produces change, and that, even if energy be only a ratio of variables within a changing field, there is still the implication of Force as the real Cause of which the change itself, however formulated, is the effect. No doubt this is one of the meanings which the ambiguous words force and cause may carry. It is to remove this ambiguity that I have suggested that the word Source should be subst.i.tuted for cause in this sense. And what about force? In one of its meanings it now generally stands for a measure of change. For those who accept Source as a scientific concept it may well stand for the measure or degree of its activity gauged by the phenomenal effect; for those who do not accept it, the measure or degree of the change itself[44]--to be dealt with in mechanics in terms of ma.s.s and acceleration. This leaves outstanding, however, the use of the word force in the phrase--the forces of nature--gravitative force, cohesive force, electromotive force, and so on. It was, I take it, with this usage in view that Spencer spoke of vital, mental, and social forces. Now the reference in each of these cases is to some specific mode of relatedness among the things concerned. We need to name it in some way; and this is the way that is, rather unfortunately, sanctioned by custom and long usage. When we say that a thing is in a field of electromotive force we mean (do we not?) that the relatedness is of that particular kind named electromotive, and not of another kind. When Spencer spoke of social forces he had in view changes which take place within a field of social relations.h.i.+ps. We do not really need the word force in this sense, since the term relatedness would suffice, and has no misleading a.s.sociations.

But there it is: our business should be to understand clearly what it means. It does not, or should not, I think, mean more, in this connexion, than a particular kind of relatedness in virtue of which an observable kind of change occurs.

We may now pa.s.s to cause and conditions. When Spencer distinguishes between those conspicuous antecedents which we call the causes and those accompanying antecedents which we call the conditions, he invites the question: What, then, is the essential difference between them? If the accompanying antecedents are distinguished as inconspicuous, we surely need some criterion of the distinction. Furthermore, inconspicuous conditions are, in science, every whit as important as those which are conspicuous. Now we all know that Mill regarded the cause as 'the sum total of the conditions positive and negative taken together.'[45] But he expressly distinguishes between _events_ and _states_.[46]

Discussing, for example, the case of a man who eats of a particular dish and dies in consequence, he says:

'The various conditions, except the single one of eating the food, were not events but states possessing more or less of permanency, and might therefore have preceded the effect by an indefinite length of duration, for want of that event which was requisite to complete the required concurrence of conditions.'

Again he says:

'When sulphur, charcoal, and nitre are put together in certain proportions and in a certain manner, the effect is, not an explosion, but that the mixture acquires a property by which in given circ.u.mstances it will explode. The ingredients of the gunpowder have been brought into a state of preparedness for exploding as soon as the other conditions of an explosion shall have occurred.'

And he tells us that physiological processes 'often have for the chief part of their operation to predispose the const.i.tution to some mode of action'.

This distinction may profitably be carried further and emphasized in our terminology. Take any thing, or any integrated group of things, regarded as that higher order of thing which we call a self-contained system. Process occurs therein, and process involves change. In so far as the system is self-contained its changes and states are inherent in its const.i.tution. We need a term by which to designate that which is thus inherent and const.i.tutional. The term _ground_ might be reserved for this purpose. The word ground has its natural home in logic. It is here extended (if it be an extension) to that to which the logic has reference in the existing world. One is here following Spencer, who claims[47] that 'Logic is a science pertaining to objective existence'.

On these terms the const.i.tution of any system is the ground of the properties, states, and happenings in that system regarded as isolated.

But the changes or properties will be also in relation to surrounding things or systems. _These_ changes, or modifications of change, in relation to external things or events, may properly be said to be conditioned; and we may well restrict the term conditions to influences _outside_ the const.i.tution as ground. Of course, if we accept this usage, we must not speak, with Mill, of the const.i.tution of any system as the condition of its inherent changes or properties. That is why we need some such word and concept as ground. Now we may fix our attention on any const.i.tuent part of some natural system and make that part the centre of our interest. That part may be changing in virtue of its const.i.tution; and the rest of the system, regarded as external to this selected part, must therefore be regarded as conditioning. It is a matter of convenience for purposes of scientific interpretation whether we select a larger or a smaller system-group and discuss its const.i.tutional character. Thus we may think of the const.i.tution of the solar system, or of that of the sun's corona; of the const.i.tution of an organism or of that of one of its cells; of the const.i.tution of a complex molecule or of that of an atom therein. We have here reached, or nearly reached, the limiting case in one direction--that of restricting our field of inquiry. The limiting case in the other direction is, I suppose, the universe. But could we so expand our thought as to embrace, if that were possible, the whole universe, then there are no conditions; for _ex hypothesi_ there is nothing for science outside the universe. We have reached the limiting concept. Hence, for science, the const.i.tution of nature is the ultimate ground of all that is or happens.

Let us now see how we stand. Consider the following statements:

1. The Unknowable is the cause of all the phenomena we observe.

2. The const.i.tution of gunpowder is the cause of its explosiveness.[48]

3. The fall of a spark was the cause of the actual explosion of the powder.[49]

Or these: