Chapter II.
Schopenhauer in this chapter traces historically the forms in which the principle had been stated by his predecessors, and their influence. He points out that in Greek philosophy it appeared in two aspects—that of the necessity of a ground for a logical judgment, and that of a cause for every physical change—and that these two aspects were systematically confounded. The Aristotelian division, not of the forms of the principle itself, but of one of its aspects, the causal, exemplified a confusion which continued throughout the Scholastic period. Descartes succeeds no better. His proof of the existence of God that the immensity of His nature is a cause or reason beyond which no cause is needed for His existence, simply illustrates the gross confusion between cause [pg 479] and ground of knowledge which underlies every form of this ontological proof. “That a miserable fellow like Hegel, whose entire philosophy is nothing but a monstrous amplification of the ontological proof, should dare to defend this proof against Kant's criticism of it is an alliance of which the ontological proof itself, little as it knows of shame, might well feel ashamed. It is not to be expected I should speak respectfully of people who have brought philosophy into disrespect.” Spinoza made the same confusion when he laid it down that the cause of existence was either contained in the nature and definition of the thing as it existed, or was to be found outside that thing. It was through this confusion of the ground of knowledge with the efficient cause that he succeeded in identifying God with the world. The true picture of Spinoza's “Causa sui” is Baron Munchhausen encircling his horse with his legs, and raising himself and the horse upwards by means of his pigtail, with the inscription “Causa sui” written below. Leibnitz was the first to place the principle of sufficient reason in the position of a first principle, and to indicate the difference between its two meanings. But it was Wolff who first completely distinguished them, and divided the doctrine into three kinds: principium fiendi (cause), principium essendi (possibility), and principium cognoscendi. Baumgarten, Reimarus, Lambert, and Platner added nothing to the work of Wolff, and the next great step was Hume's question as to the validity of the principle. Kant's distinction of the logical or formal principle of knowledge—Every proposition must have its ground; from the transcendental or material principle, Every thing must have its ground—was followed out by his immediate successors. But when we come to Schelling we find the proposition that gravitation is the reason and light the cause of things, a proposition which is quoted simply as a curiosity, for such a piece of nonsense deserves no place among the opinions of earnest and honest inquirers. The chapter concludes by pointing out the futility of the attempts to prove the principle. Every proof is the exhibition of the ground of a judgment which has been expressed, and of which, just because that ground is exhibited, we predicate truth. The principle of [pg 480] sufficient reason is just this expression of the demand for such a ground, and he who seeks a proof, i.e., the exhibition of a ground for this principle itself, presupposes it as true, and so falls into the circle of seeking a proof of the justification of the demand for proof.