I have reread parts of On War and I'm more deeply impressed after the first read. No wonder it is the most influential book in current military thought. New thoughts spring into your eyes everywhere. John Keegan sadly truly exposes his utter ignorance when criticizing it and seems to have never read it. Even for some "scholars" the philosophy of science is a hard beast to tackle, especially for Angloamericans with their sombre reliance on positivism.