Leibniz's critique of Locke's views concerning the limits and extent of human knowledge

Abstract

Knowledge, for Locke, consists in perceiving agreement between ideas, i.e., roughly either (a) the perception of necessary truth, or (b) the perception of certain facts about oneself. He subsequently includes sensitive knowledge concerning objects actually present to the senses. Leibniz holds a less strict position. There can be no knowledge without ideas and, for Locke, there can be no ideas without the appropriate experience. Leibniz, even after heavily qualifying Locke's view, still seems to disagree. Locke distinguishes "identical" from "non-identical" necessary truths and suggests that the former are all trifling. Leibniz holds that all necessary truths are identical but does not argue for the possibility of discovering necessary truth. Locke also suggests that the knowledge of identical necessary truths, and on occasion even of non-identical truths, consists simply in the knowledge of the uses of words. Leibniz rejects such nominalistic tendencies. For Locke, knowledge of existence is confined to that of oneself, God, and objects actually present to the senses. Leibniz holds a more liberal view, appealing to the reasonableness of the claim that there are external objects not actually present to the senses - a reasonableness which Locke recognises. Human knowledge of general truths in science and metaphysics is virtually impossible for Locke because one can perceive very few logical connections. Leibniz again objects on the grounds that Locke is demanding too much for knowledge, but also because he feels there are greater possibilities of knowledge here in Locke's sense - or at least that there is more a priori knowledge possible here than Locke allows. In view of points raised above, Leibniz remains chiefly a rationalist. Locke's case is not so clear. Aside from his position on the origin of ideas, and save for leanings towards empiricism, Locke is in certain respects even more of a rationalist than Leibniz.