Many years ago, when studying the Aristotelian rhetoric at Oxford, it struck us that, by whatever name Aristotle might describe the main purpose of rhetoric, practically, at least, in his own treatment of it, he threw the whole stress upon finding such arguments for any given thesis as, without positively proving or disproving it, gave it a colorable support. We could not persuade ourselves that it was by accident that the topics, or general heads of argument, were never in an absolute and unconditional sense true.