'...This then is the knowledge which Greek philosophy meant: not mere intellect though 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 science the most perfect he can find acknowledged is only an ouverture or perhaps only the preliminary tuning of the strings. It is a knowledge not eternally hypothetical a 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...