Part 9

It will not be amiss, before passing from this subject, to take note of and to ponder that certainty which, in trying to recollect something, we have of our possession of what we are thus striving to gain consciously, though we are not conscious what it is. We have the clearest conviction that, although we have forgotten it, we still have it and may recover it. How comes it to pass that we are so sure of the existence of that of which we are not conscious? In the first place, it would appear to supply an argument in support of the theory that something has been left behind in the nerve-circuit ministering to the forgotten idea, in other words, retained by it, which differentiates it from other nerve-circuits, disposes it to a repetition of its former activity, and produces the conviction of a latent possession, even when it is not active, or at any rate not active enough to awaken consciousness. In the second place, it must be remembered that the forgotten idea had associations with other ideas, which are really part of its meaning; it may well be, therefore, that when these are active and occupy the attention, while it remains inactive and below the horizon of consciousness, there is a tendency or sort of effort to reopen the former paths of association, in order to their completeness--to make the circuit, so to speak; and that it is the consciousness of this tendency or effort which gives rise to the certainty which we have of something forgotten. Certain it is, that when a stimulus excites one of two movements which have taken place together or in succession on former occasions, there is a tendency, when the stimulus is powerful or continued, to the reproduction of the associated movement; there is a diffusion of the stimulus along the accustomed path to the associated motor centres, and a union of movements is the result. A piece of poetry which has been thoroughly learnt may be repeated mechanically, as a tune may be whistled, when the proper verbal movements have been once started; indeed, the repetition in such case is most successful when consciousness is not too much occupied with it; for it frequently happens, if we think about the words which we are repeating, we become uncertain and forget, and are obliged, in order to succeed, to begin again and allow the succession of movements to go on automatically. We impede the operation of the spontaneous memory, upon which we really depend, when, by maintaining the activity of a word in consciousness as attention, we hinder the propagation thereof to the associated nerve-circuits.

When a person who is conscious of an idea is striving to revive a related idea which he has forgotten, he presents an example of memory in the making; for he is striving to revive the yet incomplete organic union between them, which was the result of the original apprehension of their relations, and which, when complete, will cause the one idea to recall the other instantly and without the least effort, just as a single sensation of an object at once revives the cluster of sensations which are combined in the perception of it. The process of intellectual development consists in the mental organization of related ideas, as internal representatives of external relations in nature, and in making this organization so complete that a number of associated ideas shall act like a single idea, being combined into a complex product and recalled instantly and without conscious effort, just as a complex movement is. Then the memory is so complete that we must cease to call it memory, because it is unconscious. In fact, spontaneous recollection is at an end when involuntary memory begins, and involuntary memory merges gradually into a reproduction of former mental experiences which is as completely automatic as the habitual movements of our daily life. And well it may be; for the same organic property of nerve element--indeed, I might say, the same fundamental property of organization--is at the bottom of both.

Thus much concerning the nature and function of memory. Upon its basis rests the possibility of mental development, in which there are, as we have already seen, the organic registration of the _simple_ ideas of the senses; the assimilation of the like in ideas which takes place in the production or evolution of _general_ ideas; the assimilation, of the properties common to two or more general ideas into an _abstract_ idea; the special organization or differentiation, or discrimination, of unlike ideas; the organic combination of the ideas derived from the different senses into one _complex_ idea, with the further manifold combinations of complex ideas into what Hartley called _duplex_ ideas. In fact, no limit is assignable to the complexity of combinations which may go to the formation of a compound idea. Take, for example, the idea of the universe. But how comes it to pass that a new imaginative creation of the mind, to which nothing in nature answers, is effected? By the same process fundamentally as that by which our general and abstract ideas are formed. For when we consider the matter, it appears that there are no actual outside existences answering to our most abstract ideas, which are, therefore, so far new creations of the mind; in their formation there is a blending or coalescence of the like relations in two concrete ideas--the development of a _concept_, there is, as it were, an extraction of the essential out of the particular, a sublimation of the concrete; and, by the creation of a new world in which these essential ideas supersede the concrete ideas, the power of the mind is most largely extended. Now, although there are no concrete objects in nature answering to these abstract ideas, yet these are none the less, when rightly formed, valid and real subjective existences expressing or signifying the essential relations of things, as the flower which crowns development expresses the essential nature of the plant. Thus it is that we rise from the idea of a particular man to the general idea of man, and from that to the abstract idea of virtue as a quality of man; so that for the future we can make use of the abstract idea in all our reasoning, without being compelled to make continual reference to the concrete. Herein, be it remembered again, we have a process corresponding with that which ministers to the production of our motor intuitions; the acquired faculty of certain co-ordinate movements by means of which complicated acts are automatically performed, and we are able to do, almost in the twinkling of an eye, what would cost hours of labour were we compelled on each occasion to go deliberately through the process of special adaptation, is the equivalent, on the motor side, of the general idea by which so much time and labour are saved in reasoning: in both cases there is an internal development in accordance with fundamental laws, and the organized result is, as every new phase of development is, a new creation. Creation is not by fits and starts, but it is continuous in nature.

COMMON SENSE

WILLIAM BOYD CARPENTER, M.D.

[Dr. Carpenter was one of the leading men of science in the generation which has recently passed away. He was a physician and psychologist of mark, and withal a geographer of erudition and extensive travel. His famous work, "Principles of Mental Physiology," is published by D. Appleton & Co., New York. Its eleventh chapter, minus a few paragraphs, is here presented.]

There are two principal forms of common sense which it is desirable clearly to distinguish. The first is what the philosopher means by common sense, when he attributes to it the formation of those original convictions or ultimate beliefs, which cannot be resolved into simpler elements, and which are accepted by every normally constituted human being as direct cognitions of his own mental states. It might, indeed, be maintained that this necessary acceptance of propositions which only need to be intelligibly stated to command unhesitating and universal assent, cannot rightly be termed an act of judgment. But just as sense-perceptions, which are intuitive in the lower animals, have been acquired in man by a process of self-education in the earliest stages, in which acts of judgment are continually called for, so may we regard the autocratic deliverances of the universal common sense of mankind as really having, in the first instance, the characters of true judgments, each expressing the general resultant of uniform experience,--which may be partly of the individual, and partly that of the race embodied in the constitution of each member of it.

The second or popular acceptance of the term common sense, on the other hand, is that of an attribute which judges of things whose self-evidence is not equally apparent to every individual, but presents itself to different individuals in very different degrees, according in part to the original constitution of each, and in part to the range of his experience and degree in which he has profited by it. This is the form of common sense by which we are mainly guided in the ordinary affairs of life: but inasmuch as we no longer find its deliverances in uniform accordance, but encounter continual divergences of judgment as to what things are self-evident,--some being so to A whilst they are not so to B, and others being self-evident to B which are not so to A,--it cannot be trusted as an autocratic or infallible authority. And yet, as Dr. Reid truly says, "disputes very often terminate in an appeal to common sense;" this being especially the case, when to doubt its judgment would be ridiculous.

If the view here taken be correct, these two forms--which may be designated respectively as elementary and as ordinary common sense--have fundamentally the same basis; and we may further connect with them as having a similar genesis, those special forms of common sense, which are the attributes of such as have applied themselves in a scientific spirit to any particular course of inquiry,--things coming to be perfectly self-evident to men of such special culture, which ordinary men, or men whose special culture has lain in a different direction, do not apprehend as such.

The judgment of common sense as to any self-evident truth, may be defined as the immediate or instinctive response that is given (in psychological language) by the automatic action of the mind, or (in physiological language) by the reflex-action of the brain to any question which can be answered by such a direct appeal. The nature and value of that response will depend upon the acquired condition of the mind, or of the brain, at the time it is given; that condition being the general resultant of the whole psychical activity of the individual. The particular form of that activity is determined, as we have seen, in the first place, by his original constitution; secondly, by the influences which have been early brought to bear upon it from without; and thirdly, by his own power of self-direction. And it may be said that while the elementary form of common sense depends mainly upon the first of these factors, its ordinary form chiefly arises out of the first and second, and its special forms almost exclusively out of the third;--the response being given, in each case, by a nervous mechanism, in the organization of which the generalized results of the past experiences of consciousness (whether of the race or of the individual) have become embodied.

The parallel between the cerebral action which furnishes the mechanism of thought now under consideration, and the action of the sensori-motor apparatus which furnishes the mechanism of sense and motion, is extremely close. We have seen that there are certain sense-perceptions, which, although not absolutely intuitive, very early come to possess--in every normally constituted human being--the immediateness and perfection of those corresponding perceptions which are intuitive in the lower animals; and that with these are associated certain respondent motions, which, though acquired by practice in the first instance, ultimately come to be performed as by a second nature. Certain of these motions, such as walking erect, are universally acquired; and thus obviously come to be the expressions of the original endowments of the mechanism, trained by an experience very similar in the uniformity of its character to that which educates the elementary form of common sense. For it must be clear to any one who compares the erect progression of a child who has just learned to walk, with that of a dancing dog or even of a chimpanzee, that while experience makes its acquirement possible in each case, only an organism which is at the same time structurally adapted for erect progression and possessed of a special co-ordinating faculty, can turn such experience to full account. The balancing the body in the erect position at starting, the maintenance of that balance by a new adjustment of the centre of gravity as the base of support is shifted from side to side and from behind forwards, and the alternate lifting and advance of the legs, involve the harmonious co-operation of almost all the muscles in the body. Although this co-operation is brought about in the first instance by the purposive direction of our efforts towards a given end, under the guidance of our visual and muscular sensations, yet when we have once learned to walk erect, we find ourselves able to maintain our balance without any exertion of which we are conscious; all that is necessary for the performance of this movement being that a certain stimulus (volitional, or some other) shall call the mechanism into activity.--But further, we have seen that special powers of sense-perception can be acquired by the habitual direction of the attention to particular classes of objects; and that special movements come to be the secondarily automatic expression of them. How nearly related these are to the preceding, we may assure ourselves by attending to the process by which an adult learns to walk on a narrow base, such as a rope or the edge of a plank. For the co-ordinating action has here to be gone through afresh under altered and more special conditions, so as to give a greater development to the balancing power; yet when this has been fully acquired, it is exerted automatically with such an immediateness and perfection, that a Blondin can cross Niagara on his rope with no more danger of falling into the torrent beneath, than any ordinary man would experience if walking without side-rails along the broad platform of the suspension bridge which spans it. Now since in those cases in which man acquires powers that are original or intuitive in the lower animals, there is the strongest reason for believing that a mechanism forms itself in him which is equivalent to that congenitally possessed by them, we seem fully justified in the belief that in those more special forms of activity which are the result of prolonged training, the sensori-motor apparatus grows to the mode in which it is habitually exercised, so as to become fit for the immediate execution of the mandate it receives: it being often found to act not only without intelligent direction, but without any consciousness of exertion, in immediate response to some particular kind of stimulus,--just as an automaton that executes one motion when a certain spring is touched, will execute a very different one when set going in some other way.

There is strong analogical ground, then, for the belief that the higher part of the nervous mechanism which is concerned in psychical action, will follow the same law; embodying the generalized result of its experiences, so as to become able to evolve, by a direct response, a result of which the attainment originally required the intervention of the conscious mind at several intermediate stages of the process. What there is strong ground for believing in regard to the perceptional consciousness, may fairly be extended to the ideational, which is so intimately connected to it, the unconscious co-ordinating action, which in the former case brings the whole experience to bear upon the question, whilst the decisions of the latter are based upon a limited, and therefore one-sided, view of it,--the defect of judgment being due either to an original want of the co-ordinating power, or to disuse of the exercise of it through the limitation of the attention to special fields of study. It may often be noticed that children display a power of bringing common sense to bear upon the ordinary affairs of life, which seems much beyond that of their elders; and yet a very sensible child will often grow into a much less sensible man. Now the reason of this seems to be, that the child perceives the application of self-evident considerations to the case at issue, without being embarrassed by a number of other considerations (perhaps of a trivial or conventional nature) which distract the attention and unduly influence the judgment of the adult. And the deliverances of a child's common sense thus often resemble those of the old court fools, or jesters, whose function seems to have been to speak out home truths which timid courtiers would not venture to utter. Moreover, as has been well remarked, "it is quite possible for minds of limited power to manage a small range of experience much better than a large, to get confused (as it were) with resources on too great a scale, and therefore to show far more common sense within the comparatively limited field of childish experience, than in the greater world of society or public life. This is probably the explanation of a thing often seen,--how very sagacious people instinctively shrink from a field which their tact tells them is too large for them to manage, and keep to one where they are really supreme."

Now, in so far as our conscious mental activity is under the direction of our will, we can improve this form of common sense, as to both its range and the trustworthiness of its judgments, by appropriate training. Such training, as regards the purely intellectual aspect of common sense, will consist in the determinate culture of the habit of honestly seeking for truth,--dismissing prejudice, setting aside self-interest, searching out all that can be urged on each side of the question at issue, endeavouring to assign to every fact and argument its real value, and then weighing the two aggregates against each other with judicial impartiality. For in proportion to the steadiness with which this course is volitionally pursued, must be its effectiveness in shaping the mechanism whose automatic action constitutes the unconscious thinking, of which the results express themselves in our common-sense judgments.

The ordinary common sense of mankind, disciplined and enlarged by an appropriate culture, becomes one of the most valuable instruments of scientific inquiry; affording in many instances the best and sometimes the only basis for a rational conclusion. A typical case, in which no special knowledge is required, is afforded by the flint implements of the Abbeville and Amiens gravel beds. No logical proof can be adduced that the peculiar shapes of these flints were given to them by human hands; but no unprejudiced person who has examined them now doubts it.

The evidence of design to which, after an examination of one or two such specimens, we should only be justified in attaching a probable value, derives an irresistible cogency from accumulation. On the other hand, the improbability that these flints acquired their peculiar shape by accident, becomes to our minds greater and greater as more and more such specimens are found; until at last this hypothesis, although it cannot be directly disproved, is felt to be almost inconceivable, except by minds previously possessed by the dominant idea of the modern origin of man. And thus what was in the first instance a matter of discussion, has now become one of those self-evident propositions, which claim the unhesitating assent of all whose opinion on the subject is entitled to the least weight.

We proceed upwards, however, from such questions as the common sense of mankind generally is competent to decide, to those in which special knowledge is required to give value to the judgment; and here we must distinguish between those departments of inquiry in which scientific conclusions are arrived at by a process of strict reasoning, and those in which they partake of the nature of common sense judgments.

Of the former class we have a typical example in mathematics, and in those exact sciences which make use of mathematics as their instrument of proof; but even in these, it is common sense which affords not only the basis, but the materials of the fabric. For while the axioms of geometry are self-evident truths which not only do not require proof, but are not capable of being proved in all their universality, every step of a demonstration is an assertion of which our acceptance depends on our incapability of conceiving either the contrary or anything else than the thing asserted. And thus the certain assurance of the proof felt by every person capable of understanding a mathematical demonstration, depends upon the conclusive self-evidence of each step of it. But we not unfrequently meet with individuals, not deficient in ordinary common sense, who cannot be brought to see this self-evidence; whilst, on the other hand, the advanced mathematician, when adventuring into new paths of inquiry, is able to take a great deal for granted as self-evident, which at an earlier stage of his researches would not have so presented itself to his mind. The deliverances of this acquired intuition can in most cases be readily justified by the reasoning process which they have anticipated. But the genius of a mathematician--that is, his special aptitude developed by special culture--will occasionally enable him to divine a truth, of which, though he may be able to prove it experientially, neither he nor any other can at the time furnish a logical demonstration. In this divining power we have clear evidence of the existence of a capacity which cannot be accounted for by the mere co-ordination of antecedent experiences, whether of the individual or of the race; and yet, as already shown, such co-ordination has furnished the stimulus to its development.

Of those departments of science, on the other hand, in which our conclusions rest (like those of ordinary common sense) not on any one set of experiences, but upon our unconscious co-ordination of the whole aggregate of our experiences,--not on the conclusiveness of any one train of reasoning, but on the convergence of all our lines of thought towards one centre,--geology may be taken as a typical example. For this inquiry brings (as it were) into one focus, the light afforded by a great variety of studies,--physical and chemical, geographical and biological; and throws it on the pages of that great stone book in which the past history of our globe is recorded. And its real progress dates from the time when that common sense method of interpretation came to be generally adopted, which consists in seeking the explanation of past changes in the forces at present in operation, instead of invoking (as the older geologists were wont to do) the aid of extraordinary and mysterious agencies.