Mens ideas are the most direct emanations of their material state. – Karl Marx
The product of mental labor – science – always stands far below its value, because the labor-time necessary to reproduce it has no relation at all to the labor-time required for its original production. – Karl Marx
The ideas of the ruling class are in every epoch the ruling ideas, i.e., the class which is the ruling material force of society, is at the same time its ruling intellectual force. – Karl Marx
Capitalist production, therefore, develops technology, and the combining together of various processes into a social whole, only by sapping the original sources of all wealth – the soil and the labourer. – Karl Marx