Since the last quarter of the nineteenth century, philosophers and historians have been involved in the controversy as to whether history provides knowledge sui generis or is a branch of science. philosophers who support the latter alternative justify their view by a logical examination of the subject-matter and methods of history, which leads them to the conclusion that the reasons advanced for a sharp differentiation of history from science are untenable. This is also the view adopted by Marxist-Leninists but they reach it by a method of their own.