A statistical study of belief.

It is a matter of common experience that our beliefs are more or less graded in a scale of certainty.Some of them we cannot conceive of our ever changing; others, although practically certain, might, conceivably at least, be subject to revision or even reversal, whilst others yet command little authority and even vary momentarily with the play of our feelings.Nor are these three main ranks of certainty all that can be distinguished.The degree of one's belief, like the intensity of any mental state, admits of an almost indefinite gradation quantitatively.But, unfortunately for our present purpose, it shares with other mental states the property of defying accurate measurement.The practical test of belief is, of course, conduct.One can be truly said to believe only what one acts as if he believes, and the gauge of his conviction is the extent to which it is embodied in his actions.Thus, although beliefs defy exact measurement, and are even to a great extent incommensurate, one with the other, their relative strength finds a common standard in their motor results.But even this does not furnish a practicable yardstick to the psychologist.All those things of which we are practically ' sure' are in our daily life absolutely coercive upon conduct.There would be no degrees distinguishable.And this, although to introspection there might be appreciable differences in the intensity or vividness with which they presented themselves to consciousness.Hence, in the present experiments, I have had recourse to the method of introspection, although this is fraught with difficulties so great as perhaps to render the results of little value.