194 ARTHUR O. LOVEJOY : it, but the passion for consistency and coherency in that conception. The greater philosophers have been distin- guished, not by a more insatiable lust for the synthesis of -abstruse ideas, but by a superior talent for the analysis of the common ideas used in all thinking. Philosophy begins, no doubt, in the case of a Thales or any similar pioneer, with a demand for completeness and ultimateness of explanation of given facts ; but if I may repeat what I have already remarked elsewhere philosophy once begun is kept going and endlessly changing by the continual fresh discovery of latent inconsistencies in the accepted interpretations of ex- perience. Every man is more or less disturbed at any intimations of the presence of such inconsistencies in his body of apparently settled opinions ; and the philosopher, as he is usually exemplified in history, is merely the man who is peculiarly alert to this situation, and peculiarly and, perhaps, unnecessarily uncomfortable at finding himself in it. Often enough, no doubt, it has been some religious or practical need that has .set him to looking for the contra- dictions in the current opinions ; but in so far as his revision of those opinions has been philosophical, the motive that shaped it has been the demand for consistency in the ex- plication of the conceptual necessities implicit in the facts of experience. We are not called upon here, however, to review the whole history of metaphysics ; and it is therefore not possible to point out in detail how, at nearly all the great steps of philosophical transition, the method, both of metaphysical criticism and of metaphysical construction, has consisted in some special application of the two logical maxims involved in the principle of contradiction, in its broader meaning : that which, after the completest analysis of the -ideas involved, implies the coinherence, in a single subject, of concepts that the mind is incapable of combining in thought, can- not be real, and that proposition of which the opposite is, in the sense just specified, inconceivable or self -contradictory, must be true. It suffices for our present purpose to recall the manifest fact that Kant's more immediate ' dogmatic ' predecessors, Leibniz, Wolff and Baumgarten, so far from constructing their metaphysical edifices without first examining the founda- tions, had been entirely explicit in naming the criterion of a priori knowledge, through the use of which metaphysics was to be possible ; a and had limited that criterion to the single 1 In his criticism of Kant Eberhard declared that " die Leibnitzische Philosophic ebensowohl eine Vernunftkritik enthalte, wie die Kantische ; denn sie griinde ihren Dogmatismus auf eine genaue Zergliederung der
