Illusions - James Sully (online e reader .txt) 📗

roughly describe all illusion as abnormal. Just as hallucination, the most signal instance of illusion, is distinctly on the border-land of healthy and unhealthy mental life; just as dreams are in the direction of such unhealthy mental action; so the lesser illusions of memory and so on are abnormal in the sense that they imply a departure from a common typical mode of intellectual action.

It is plain, indeed, that this is the position we have been, taking up throughout our discussion of illusion. We have assumed that what is common and normal is true, or answers to what is objectively real. Thus, in dealing with errors of perception, we took for granted that the common percept—meaning by this what is permanent in the individual and the general experience—is at the same time the true percept. So in discussing the illusions of memory we estimated objective time by the judgment of the average man, free from individual bias, and apart from special circumstances favourable to error. Similarly, in the case of belief, true belief was held to be that which men in general, or in the long run, or on the average, hold true, as distinguished from what the individual under variable and accidental influences holds true. And even in the case of introspection we found that true cognition resolved itself into a consensus or agreement as to certain psychical facts.

Criterion of Illusion.

Now, it behoves us here to examine this assumption, with the view of seeing how far it is perfectly sound. For it may be that what is commonly held true does not in all cases strictly answer to the real, in which case our idea of illusion would have to be extended so as to include certain common beliefs. This question was partly opened up at the close of the last chapter. It will be found that the full discussion of it carries us beyond the scientific point of view altogether. For the present, however, let us see what can be said about it from that standpoint of positive science to which we have hitherto been keeping.

Now, if by common be meant what has been shared by all minds or the majority of minds up to a particular time, a moment's inspection of the process of correcting illusion will show that science assumes the possibility of a common illusion. In the history of discovery, the first assault on an error was the setting up of the individual against the society. The men who first dared to say that the sun did not move round the earth found to their cost what it was to fly in the face of a common, though illusory, perception of the senses.[151]

If, however, by common be understood what is permanently and unshakably held true by men in proportion as their minds become enlightened, then science certainly does assume the truth of common perception and belief. Thus, the progress of the physical sciences may be described as a movement towards a new, higher, and more stable consensus of ideas and beliefs. In point of fact, the truths accepted by men of science already form a body of common belief for those who are supposed by all to have the means of testing the value of their convictions. And the same applies to the successive improvements in the conceptions of the moral sciences, for example, history and psychology. Indeed, the very meaning of science appears to be a body of common cognition to which all minds converge in proportion to their capabilities and opportunities of studying the particular subject-matter concerned.

Not only so, from a strictly scientific point of view it might seem possible to prove that common cognition, as defined above, must in general be true cognition. I refer here to the now familiar method of the evolutionist.

According to this doctrine, which is a scientific method in so far as it investigates the historical developments of mind or the order of mental phenomena in time, cognition may be viewed as a part of the result of the interaction of external agencies and the organism, as an incident of the great process of adaptation, physical and psychical, of organism to environment. In thus looking at cognition, the evolutionist is making the assumption which all science makes, namely, that correct views are correspondences between internal (mental) relations and external (physical) relations, incorrect views disagreements between these relations. From this point of view he may proceed to argue that the intellectual processes must tend to conform to external facts. All correspondence, he tells us, means fitness to external conditions and practical efficiency, all want of correspondence practical incompetence. Consequently, those individuals in whom the correspondence was more complete and exact would have an advantage in the struggle for existence and so tend to be preserved. In this way the process of natural selection, by separately adjusting individual representations to actualities, would make them converge towards a common meeting-point or social standard of true cognition. That is to say, by eliminating or at least greatly circumscribing the region of individual illusion, natural selection would exclude the possibility of a persistent common illusion.

Not only so, the evolutionist may say that this coincidence between common beliefs and true beliefs would be furthered by social as well as individual competition. A community has an advantage in the struggle with other communities when it is distinguished by the presence of the conditions of effective co-operation, such as mutual confidence. Among these conditions a body of true knowledge seems to be of the first importance, since conjoint action always presupposes common beliefs, and, to be effective action, implies that these beliefs are correct. Consequently, it may be argued, the forces at work in the action of man on man, of society on the individual, in the way of assimilating belief, must tend, in the long run, to bring about a coincidence between representations and facts. Thus, in another way, natural selection would help to adjust our ideas to realities, and to exclude the possibility of anything like a permanent common error.

Yet once more, according to Mr. Herbert Spencer, the tendency to agreement between our ideas and the environment would be aided by what he calls the direct process of adaptation. The exercise of a function tends to the development of that function. Thus, our acts of perception must become more exact by mere repetition. So, too, the representations and concepts growing out of perceptions must tend to approximate to external facts by the direct action of the environment on our physical and psychical organism; for external relations which are permanent will, in the long run, stamp themselves on our nervous and mental structure more deeply and indelibly than relations which are variable and accidental.

It would seem, from all this, that so long as we are keeping to the scientific point of view, that is to say, taking for granted that there is something objectively real answering to our perceptions and conceptions, the question of the possibility of a universal or (permanently) common illusion does not arise. Yet a little more reflection will show us that it may arise in a way. So far as the logical sufficiency of the social consensus or common belief is accepted as scientifically proved, it is open to suspicion on strictly scientific grounds. The evolutionist's proof involves one or two assumptions which are not exactly true.

In the first place, it is not strictly correct to say that all illusion involves a practical unfitness to circumstances. At the close of our investigation of particular groups of illusion, for example, those of perception and memory, it was pointed out that many of the errors reviewed were practically harmless, being either momentary and evanescent, or of such a character as not to lead to injurious action. And now, by glancing back over the field of illusion as a whole, we may see the same thing. The day-dreams in which some people are apt to indulge respecting the remote future have little effect on their conduct. So, too, a man's general view of the world is often unrelated to his daily habits of life. It seems to matter exceedingly little, in general, whether a person take up the geocentric or the heliocentric conception of the cosmic structure, or even whether he adopt an optimistic or pessimistic view of life and its capabilities.

So inadequate, indeed, does the agency of natural selection seem to be to eliminate illusion, that it may even be asked whether its tendency may not be sometimes to harden and fix rather than to dissolve and dissipate illusory ideas and beliefs. It will at once occur to the reader that the illusion of self-esteem, discussed in the last chapter, may have been highly useful as subserving individual self-preservation. In a similar way, it has been suggested by Schopenhauer that the illusion of the lover owes its force and historical persistence to its paramount utility for the preservation of the species. And to pass from a recurring individual to a permanently common belief, it is maintained by the same pessimist and his followers that what they regard as the illusion of optimism, namely, the idea that human life as a whole is good, grows out of the individual's irrational love of life, which is only the same instinctive impulse of self-preservation appearing as conscious desire. Once more, it has been suggested that the belief in free-will, even if illusory, would be preserved by the process of evolution, owing to its paramount utility in certain stages of moral development. All this seems to show at least the possibility of a kind of illusion which would tend to perpetuate itself, and to appear as a permanent common belief.

Now, so far as this is the case, so far as illusion is useful or only harmless, natural selection cannot, it is plain, be counted on to weed it out, keeping it within the narrow limits of the exceptional and individual. Natural selection gets rid of what is harmful only, and is indifferent to what is practically harmless.

It may, however, still be said that the process of direct adaptation must tend to establish such a consensus of true belief. Now, I do not wish for a moment to dispute that the growth of intelligence by the continual exercise of its functions tends to such a consensus: this is assumed to be the case by everybody. What I want to point out is that there is no scientific proof of this position.

The correspondence of internal to external relations is obviously limited by the modes of action of the environment on the organism, consequently by the structure of the organism itself. Scientific men are familiar with the idea that there may be forces in the environment which are practically inoperative on the organism, there being no corresponding mode of sensibility. And even if it be said that our present knowledge of the material world, including the doctrine of the conservation of energy, enables us to assert that there is no mode of force wholly unknown to us, it can still be contended that the environment may, for aught we know, be vastly more than the forces of which, owing to the nature of our organism, we know it to be composed. In short, since, on the evolution theory viewed as a scientific doctrine, the real external world does not directly mirror itself in our minds, but only indirectly brings our perceptions and representations into adjustment by bringing into adjustment the nervous organism with which they are somehow connected, it is plain that we cannot be certain of adequately apprehending the external reality which is here assumed to exist.

Science, then, cannot prove, but must assume the coincidence between permanent common intuitions and objective reality. To raise the question whether this coincidence is