To appreciate fully the drift of the Euthydemus, we should imagine a mental state in which not individuals only, but whole schools during more than one generation, were animated by the desire to exclude the conception of rest, and therefore the very word 'this' (Theaet.) from language; in which the ideas of space, time, matter, motion, were proved to be contradictory and imaginary; in which the nature of qualitative change was a puzzle, and even differences of degree, when applied to abstract notions, were not understood; in which there was no analysis of grammar, and mere puns or plays of words received serious attention; in which contradiction itself was denied, and, on the one hand, every predicate was affirmed to be true of every subject, and on the other, it was held that no predicate was true of any subject, and that nothing was, or was known, or could be spoken. Let us imagine disputes carried on with religious earnestness and more than scholastic subtlety, in which the catchwords of philosophy are completely detached from their context. (Compare Theaet.) To such disputes the humour, whether of Plato in the ancient, or of Pope and Swift in the modern world, is the natural enemy. Nor must we forget that in modern times also there is no fallacy so gross, no trick of language so transparent, no abstraction so barren and unmeaning, no form of thought so contradictory to experience, which has not been found to satisfy the minds of philosophical enquirers at a certain stage, or when regarded from a certain point of view only. The peculiarity of the fallacies of our own age is that we live within them, and are therefore generally unconscious of them.