`...This then is the knowledge which Greek philosophy meant: not mere intellectthough, of course, there is always a danger of theoretical inquiry degenerating into abstract and formal dogma. But of the meaning there can be no serious doubt. It is a knowledge, says Plato, to which the method of mathematical sciencethe most perfect he can find acknowledgedis only an ouverture, or perhaps, only the preliminary tuning of the strings. It is a knowledge not eternally hypotheticala system of sequences which have no sure foundation. It is a knowledge which rests upon the conviction and belief of the "idea of good": a kind of knowledge which does not come by direct teaching, which is not mere theory, but implies a lively conviction, a personal apprehension, a crisis which is a kind of "conversion," or "inspiration." It is as it were the prize of a great contest, in which the sword that conquers is the sword of dialectic: a sword whereof the property is, like that of Ithuriel`s spear, to lay bare all deceptions and illusions of life...