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 V. DISCUSSIONS. NOTE ON THE PHILOSOPHY OF A SUPPOSITION. SUPPOSITION may be defined, perhaps it would be more accurate to say it may be described, negatively, for the purposes of this paper, as a conception that is not taken to be true. The criterion of truth in the sense in which "truth " is used here is the ordinary one of agreement with facts. The phrase "not taken to be true" is in- tended to include not only conceptions that go beyond what is known, and in that sense are not taken to be true, but also con- ceptions that are at variance with what is known, that is conceptions that are known to be false, which obviously are not taken to be true : in other words, conceptions that are not known to be true, and conceptions that are known not to be true. The knowledge of opposites is one, and the opposite of supposition, as used here, is a conception that is taken to be true. The difference therefore between suppositions and other conceptions is the way in which they are viewed in relation to facts. Suppositions as here used may be divided into two classes : I. Suppositions made for their own sake suppositions that have their ends within themselves. II. Suppositions made for some other reason suppositions that are made for the sake of some extrinsic end, in relation to which they are means. Putting on one side for the moment the first division the sup- positions that are ends in themselves the second division the suppositions that are means may be subdivided teleologically, in relation to the ends they subserve. So divided, they fall into two classes : 1. Practical suppositions framed for the guidance of action, the end of which is the good. By the good in this connexion is meant not the ethically good, but the psychologically good, in other words not only what ought to be desired, but what can be desired. 2. Speculative or scientific suppositions framed to help in the attainment of truth, the end of which is, of course, the true. It would be unreal to insist on making these divisions quite mutually exclusive. In many cases a supposition may have more aspects than one, and in these cases it should be classed according to the aspect that predominates. The importance of regarding