Kant : Declaration concerning Fichte's Wissenschaftslehre , 7 Aug 1799.
. . . I hereby declare that I regard Fichte's Wissenschaftslehre as a totally indefensible system.
For pure theory of science is nothing more or less than mere logic, and the principles of logic CANNOT lead to any material knowledge, since logic, that is to say, pure logic, ABSTRACTS from the content of knowledge; he attempt to CULL ( 挑選出 ) a real object out of logic is a vain effort and therefore something that no one has ever achieved.
If transcendental philosophy is correct, such a task requires a passing over into metaphysics.
But I am so opposed to metaphysics, as defined according to Fichtean principles, that I have advised him, in a letter, to turn his fine literary gifts to the problem of applying the Critique of Pure Reason rather that SQUANDER ( 浪費, 揮霍 ) them in cultivating fruitless sophistries.
He, however, has replied politely by explaining that " he would not make light of scholasticism after all. " Thus the question whether I take the spirit of Fichtean philosophy to be a genuinely critical philosophy is already answered by Fichte himself, and it is unnecessary for me to express my opinion of its value or lack of value.
For the issue here does not concern an object that is being appraised but concerns rather the appraising subject, and so it is enough that I renounce any connection with that philosophy.
-- excerpted from Kant : Correspondence, tr. and ed. by Arnulf Zweig, p.559. CUP, 1999.