Abstract
I was prompted to write a book by re-reading Republic, Leviathan, and The Communist Manifesto for the first time in half a century and wondering how well they would stand up in the light of what present-day sociologists can fairly claim to know that Plato, Hobbes, and Marx did not. None of them were doing social science as that term is nowadays understood. But all three advance conclusions derived from evidence for how human beings do, or would, or might, behave under different environmental and historical conditions. If these arguments are bad ones, this will presumably undermine the larger purposes which the three texts are intended to serve. Or will it?