When brought to the proletariat from the capitalist class, science is invariably adapted to suit capitalist interests. What the proletariat needs is a scientific understanding of its own position in society. That kind of science a worker cannot obtain in the officially and socially approved manner. The proletarian himself must develop his own theory. For this reason he must be completely self-taught.

"The intellectuals and the workers," Die Neue Zeit, vol. 22, no. 4 (1903)