"The ideas of the ruling class are the ruling ideas in every epoch, i.e., the class which is the ruling material force of society is at the same time its ruling intellectual force. The class which has at its disposal the means of material production has at the same time at its disposal the means of intellectual production, so that, on average, the thoughts of those who lack the means of intellectual production are subject to it. The ruling ideas are nothing more than the ideal expression of the ruling material conditions, the ruling material conditions conceived as ideas; that is, the conditions that make one class the ruling class, the ideas of its rule."
Marx/Engels