Another thing to be observed with respect to these comprehensive beliefs is that where, as here, so many co-operant conditions are at work, the whole amount of common objective agreement is greatly reduced. In other words, individual peculiarities of intellectual conformation, emotional temperament, and experience have a far wider scope for their influence in these beliefs than they have in the case of presentative cognitions. At the same time, it is noteworthy that error much more rapidly propagates itself here than in the case of our perceptions or recollections. As we have seen, these beliefs all include much more than the results of the individual's own experience. They offer a large field for the influence of personal ascendency, of the contagion of sympathy, and of authority and tradition. As a consequence of this, the illusions of belief are likely to be far more persistent than those of perception or of memory; for not only do they lose that salutary process of correction which comparison with the experience of others affords, but they may even be strengthened and upheld to some extent by such social influences.
And here the question might seem to obtrude itself, whether, in relation to such a fluctuating mass of belief as that just reviewed, in which there appears to be so little common agreement, we can correctly speak of anything as objectively determinable. If illusion and error as a whole are defined by a reference to what is commonly held true and certain, what, it may be asked, becomes of the so-called illusions of belief?
This question will have to be fully dealt with in the following chapter. Here it may be sufficient to remark that amid all this apparent deviation of belief from a common standard of truth, there is a clear tendency to a rational consensus. Thought, by disengaging what is really matter of permanent and common cognition, both in the individual and still more in the class,[145] and fixing this quantum of common cognition in the shape of accurate definitions and universal propositions, is ever fighting against and restraining the impulses of individual imagination towards dissociation and isolation of belief. And this same process of scientific control of belief is ever tending to correct widespread traditional forms of error, and to erect a new and better standard of common cognition.
This scientific regulation of belief only fails where the experiences which underlie the conceptions are individual, variable, and subjective. Hence there is no definite common conception of the value of life and of the world, just because the estimate of this value must vary with individual circumstances, temperament, etc. All that can be looked for here in the way of a common standard or norm is a rough average estimate. And this common-sense judgment serves practically as a sufficient criterion of truth, at least in relation to such extreme one-sidedness of view as approaches the abnormal, that is to say, one of the two poles of irrational exaltation, or "joy-madness," and abject melancholy, which, appear among the phenomena of mental disease.[146]
CHAPTER XII.
RESULTS.
The foregoing study of illusions may not improbably have had a bewildering effect on the mind of the reader. To keep the mental eye, like the bodily eye, for any time intently fixed on one object is apt to produce a feeling of giddiness. And in the case of a subject like illusion, the effect is enormously increased by the disturbing character of the object looked at. Indeed, the first feeling produced by our survey of the wide field of illusory error might be expressed pretty accurately by the despondent cry of the poet—
"Alas! it is delusion all:
The future cheats us from afar,
Nor can we be what we recall,
Nor dare we think on what we are."
It must be confessed that our study has tended to bring home to the mind the wide range of the illusory and unreal in our intellectual life. In sense-perception, in the introspection of the mind's own feelings, in the reading of others' feelings, in memory, and finally in belief, we have found a large field for illusory cognition. And while illusion has thus so great a depth in the individual mind, it has a no less striking breadth or extent in the collective human mind. No doubt its grosser forms manifest themselves most conspicuously in the undisciplined mind of the savage and the rustic; yet even the cultivated mind is by no means free from its control. In truth, most of the illusions illustrated in this work are such as can be shared in by all classes of mind.