ONE:It is interesting to see how the most comprehensive systems of the present century, even when most opposed to the metaphysical spirit, are still constructed on the plan long ago sketched by Plato. Alike in his classification of the sciences, in his historical deductions, and in his plans for the reorganisation of society, Auguste Comte adopts a scheme of ascending or descending generality. The conception of differentiation and integration employed both by Hegel and by Mr. Herbert Spencer is also of Platonic origin; only, what with the ancient thinker was a statical law of order has become with his modern successors a dynamic law of progress; while, again, there is this distinction between the German and the English philosopher, that the former construes as successive moments of the Idea what the latter regards as simultaneous and interdependent processes of evolution.On the whole, I am afraid that my acquaintance with the modern literature of the subject will be found rather limited for an undertaking like the present. But I do not think that wider reading in that direction would have much furthered the object I had in view. That object has been to exhibit the principal ideas of Greek philosophy in the closest possible connexion with the characters of their authors, with each other, with their developments in modern speculation, with the parallel tendencies of literature and art, with the history of religion, of physical science, and of civilisation as a whole. To interpret all things by a system of universal references is the method of philosophy; when applied to a series of events this method is the philosophy of history; when the events are ideas, it is the philosophy of philosophy itself.