Karl Marx on Ideas

“When people speak of ideas that revolutionize society, they do but express the fact that within the old society, the elements of a new one have been created, and that the dissolution of the old ideas keeps even pace with the dissolution of the old conditions of existence.”

“The ideas of the ruling class are, in every age, the ruling ideas. ... The class which is the dominant material force in society is at the same time its dominant intellectual force. The class which has the means of material production at its disposal has control over the means of mental production, so that in consequence the ideas of those who lack the means of mental production are, in general, subject to it.”