ans.: New ideas, theories and discoveries emanate from material conditions, and such conditions act upon individuals.
ans.: Great men were simply ideal expressions of the hopes of some class in society that was becoming economically powerful.
ans.: Chattel slavery, serfdom, or feudal slavery and wage slavery.
ans.: The effect is detrimental to the interests of the subject class as the different class interests conflict.
ans.: Because the process of economic evolution will not permit them to remain fixed.