Professor Isaiah Berlin has written an extremely lively polemic against those metaphysical theories of history which by regarding all human actions as inevitable, make it morally improper to censure the actors. Such theories attempt to give a comprehensive explanation of historical change in terms of some abstraction such as The Masses, The Absolute Spirit, Tradition, etc. which is supposedly the real dynamism or determinant of human history. What he opposes in these theories is that they seem to entail that individuals are at the mercy of forces they are not aware of, much less understand; they have no choices or alternatives, for their actions are predetermined by the necessity of the fulfillment of some over-all Plan or Realization. Such a view if taken seriously would make it improper for the historian or anyone else to blame, say, Napoleon, or claim that he could have pursued a different policy.