ABSTRACT
These propositions are not the objects of knowledge, not because they are not true (for they well may be, and the theory is not concerned to deny that they are), but because they are contingent truths, which might conceivably be false. They carry no guarantee which provides 100 per cent insurance against their being false; and if they might conceivably be false, however remote the possibility may be, they cannot be the objects of knowledge, for knowledge cannot be wrong. Impressed with the uncertified character of contingent propositions, Descartes attempted by a systematic scrutiny to find some strict knowledge which would underwrite them, valiantly but signally failed, and by his failure led on to Hume's insistence on the uncertain character of all matter-of-fact beliefs, a form of scepticism which recent preoccupation with problems of perception has done much to perpetuate.
