Abstract
One of the primary propositions in Marxist philosophy is that thought is historical in nature. "The theoretical thought of each epoch," observed Engels, "is a historical product which takes on very different forms at different times, and also very different content" . Accordingly, any analysis of the nature of thought in general that does not consider its historical character is either incomplete or may result in false conclusions. Naturally, what we are talking about is substantive thought, i.e., thought that proceeds on a basis of elaboration and development of definite principles relating to the structure and evolution of material existence, and that is expressed in terms of knowledge concerning nature, society, and man