[124] ALL true criticism of philosophic doctrine, as of every other product of human mind, must begin with an historic estimate of the conditions, antecedent and contemporary, which helped to make it precisely what it was. But a complete criticism does not end there. In the evolution of abstract doctrine as we find it written in the history of philosophy, if there is always, on one side, the fatal, irresistible, mechanic play of circumstance--the circumstances of a particular age, which may be analysed and explained; there is always also, as if acting from the opposite side, the comparatively inexplicable force of a personality, resistant to, while it is moulded by, them. It might even be said that the trial-task of criticism, in regard to literature and art no less than to philosophy, begins exactly where the estimate of general conditions, of the conditions common to all the products of this or that particular age--of the "environment"-- leaves off, and we touch what is unique in the individual genius [125] which contrived after all, by force of will, to have its own masterful way with that environment. If in reading Plato, for instance, the philosophic student has to re-construct for himself, as far as possible, the general character of an age, he must also, so far as he may, reproduce the portrait of a person. The Sophists, the Sophistical world, around him; his master, Socrates; the Pre-Socratic philosophies; the mechanic influence, that is to say, of past and present:--of course we can know nothing at all of the Platonic doctrine except so far as we see it in well-ascertained contact with all that; but there is also Plato himself in it. --A personality, we may notice at the outset, of a certain complication. The great masters of philosophy have been for the most part its noticeably single-minded servants. As if in emulation of Aristotle's simplicity of character, his absorbing intellectualism-- impressive certainly, heroic enough, in its way--they have served science, science in vacuo, as if nothing beside, faith, imagination, love, the bodily sense, could detach them from it for an hour. It is not merely that we know little of their lives (there was so little to tell!) but that we know nothing at all of their temperaments; of which, that one leading abstract or scientific force in them was in fact strictly exclusive. Little more than intellectual abstractions themselves, in them [126] philosophy was wholly faithful to its colours, or its colourlessness; rendering not grey only, as Hegel said of it, but all colours alike, in grey.