everywhere is to distinguish knowledge from opinion, hence the precision of scientific language, hence the peculiar prominence of dialectics, which have no other object than the idea of science; things which were not comprehended even by the Eleatics in the same way as by the Socratic schools, since the former still make the idea of being their starting-point, rather than that of knowledge.
Now this waking of the idea of science, and its earliest manifestations, must have been, in the first instance, what constituted the philosophical basis in Socrates; and for this reason he is justly regarded as the founder of that later Greek philosophy,which in its whole essential form, together with its several variations, was determined by that idea. This is proved clearly enough by the historical statements in Plato, and this too is what must be supplied in Xenophon's conversations, in order to make them worthy of Socrates, and Socrates of his admirers. For if he went about in the service of the god, to justify the celebrated oracle, it was impossible that the utmost point he reached could have been simply to know that he knew nothing; there was a step beyond this which he must have taken, that of knowing what knowledge was. For by what other means could he have been enabled to declare that which others believed themselves to know, to be no knowledge, than by a more correct conception of knowledge, and by a more correct method founded upon that conception? And every where, when he is explaining the nature of non-science (ἀνεπιστημοσύνη), one sees that he sets out from two tests: one, that science is the same in all true thoughts, and consequently must manifest its peculiar form in every such thought: the other, that all science forms one whole. For his proofs always hinge on this assumption: that it is impossible to start from one true thought, and to be entangled in a contradiction with any other, and also that knowledge derived from any one point, and obtained by correct combination, cannot contradict that which has been deduced in like manner from any other point; and while he exposed such contradictions in the current conceptions of mankind, he strove to rouse those leading ideas in all who were capable of understanding, or even of divining his meaning. Most of what Xenophon has preserved for us may be referred to this object, and the same endeavour is indicated clearly
