According to Hume, ' an opinion or belief is nothing but an idea that is different from a fiction, not in the nature or in the order of its parts, but in the manner of its being conceived. But when I would explain this manner, I scarce find any word that fully answers the case, but am obliged to have recourse to every one's feeling, in order to give him a perfect notion of this operation of the mind. An idea assented to feels different from a fictitious idea that the fancy presents to us ; and this feeling I endeavour to e-xplain by calling it a superior force, or vivacity, or solidity or firmness, or steadiness' (Hume's Wor/:s, i. 397 f.. Green's ed.). The description of belief given by Hume is distinguished by tlie absence of that 'objective control of subjective activity' which, according to Professor Stout, is the mark of all belief. A closer examination of Hume's state- ment enables us to see that the superior force or vivacity of a belief is due not merely to the manner of conceiving it, but to a certain coercive- ness which fact has and which a fancy has not. The feeling of belief is not a gratuitous addition made by the mind to the experience, it is dictated by the fact itself.
Without entering into the discussion in any detail, it is sufficient for the jDresent purpose to say that all belief in the first place is teleological, that it is the tendency of tlie mind to make itself at home in the world in which it has to live. This general description includes the naive uncritical belief of the child, and the reasoned critical belief of the mature man. In its simplicity it is a pos- tulate. It may be almost called an instinct, an expectation that the world will afford to man a place in which to live and grow and w'ork. Be the origin and character of instinct what they may, be they due to original endowment or to the accumu- lated and transmitted inheritance of the race, yet the instincts are there, and are of a kind to enable life to act before individual experience has had time to work. Our organic nature is related to its environment, and it jiostulates an environment with which it (viii intciart. Thus all our organic instincts w liich liml .'xprussion in appropriate acts, such as siickiii;:, ,;iiiiiL;, moving our limbs in re- sponse to a .Ntiiuulu.s, and so on, are called into action on the presentation of their appropriate objects. Action begets belief, and Ijelicf is again the mental situation which leads to further action. At the outset belief is dominated by our practical needs. In truth, the new school of Humanism holds that all aetiWties whatsoever are in the interest of the practical needs of man, and by
the emphasis it has laid on this aspect it has called attention to a factor of human experience which has been too much neglected. For there is no doubt that the character of belief is to be explained, in the first place at all events, from its function in relation to the practical needs of man. And all through the experience of man, belief is an expression of human need, and is the demand which a living creature makes on the Universe for a place to live in, to grow in, and to furnish itself witli what shall satisfy its need. Thus the initial postulate of belief is that it is in a world in whicli it may make itself at home, and the final demand of belief in developed liuuiuiiity is that it shall find itself in a rational, inhllivil'.lc woi Id, in which its ideals of unity, iiil'ili,-iliilit\ , lieauty, and worth may and will find thcii re;tliz:itiun.
Our beliefs, then, in their generality are our postulates. They set forth our expectations, our desires, our wishes. They proceed on the assump- tion that our needs are related to reality, and that reality has a way of satisfying our needs. In all belief there is, of course, a certain risk. We may mistake our real needs, and we may make mistakes as to the nature of reality. But the postulate is there notwithstanding. In fact, to believe that a thing exists is to act as if it existed. To believe that the properties of a thing are so and so, is to act on that supposition. Thus, apart from any theory, we all postulate a kind of uniformity of nature.
From this point of view all axioms are pos- tulates. They are unavoidable assumptions. Students of science are familiar with these. We do not at present raise the question whether the universal formulae of science are more than pos- tulates. They are postulates, and are demands which our nature makes on the Universe.
Our postulates, however, moi/ mislead ; they may be unwarrantable, and not unavoidable. Along, therefore, with the predisposition to believe in the reality and modes of being of the objects of experience, there goes the necessity of verification, criticism, and investigation. For postulates may be too readily made. Passing needs may be taken for permanent, and beliefs may be based on wrong impressions. Subjective hopes or fears may ob- jectify their objects, and attribute reality to objects which have nonp. Tliu=! wc Iiave beliefs which are irresistible an. I uii;i\ ni.l.iblr.. They are absolutely based in the icnstitutiiui ni the mind itself, and are the assnmi.tioiis without which experience is impossible. Students of Kant will readily recognize them. They lie at the basis of our life and activity, they are acted on before we are conscious of them, and when they arise into clear consciousness we recognize that they are unavoidable and inevitable. In like manner" there are other principles arising out of our intercourse with the external world which strike us as in- evitable and unavoidable. To enumerate these would lead us too far afield.