My logic deserves its proletarian qualification for the reason that it requires for its understanding the overcoming of all prejudices by which the c… - Joseph Dietzgen

Much of what I have to say for my case may sound wonderful, because it runs counter to the popular prejudice, but the only witness required to prove the truth of my statements is the clear brain of my pupil, who has only to examine his own experience without preconceived notions, in order to find proofs on every hand.

The materialist theory of knowledge amounts, then, to this statement, that the human organ of cognition radiates no metaphysical light, but is a piece of Nature which pictures other pieces of Nature whose essence is explained when we describe it and bring it in connection with the whole Universe as the one Reality and the real Unity. Such a description demands from the epistemologist or philosopher that he should treat his subject in the same precise way as the animal world is treated by the zoologist. Should I be reproached with not following this precept immediately, I would point to Rome which, too, was not built in one day.

Adherents of formal logic may be compared to a maker of porcelain dishes who would contend that he was simply paying attention to the form of his dishes, pots, and vases, but that he did not have anything to do with the raw material.