THREE:There still remained one last problem to solve, one point228 where the converging streams of ethical and metaphysical speculation met and mixed. Granted that knowledge is the souls highest energy, what is the object of this beatific vision? Granted that all particular energies co-operate for a common purpose, what is the end to which they are subordinated? Granted that dialectic leads us up through ascending gradations to one all-comprehensive idea, how is that idea to be defined? Plato only attempts to answer this last question by re-stating it under the form of an illustration. As the sun at once gives life to all Nature, and light to the eye by which Nature is perceived, so also the idea of Good is the cause of existence and of knowledge alike, but transcends them both as an absolute unity, of which we cannot even say that it is, for the distinction of subject and predicate would bring back relativity and plurality again. Here we seem to have the Socratic paradox reversed. Socrates identified virtue with knowledge, but, at the same time, entirely emptied the latter of its speculative content. Plato, inheriting the idea of knowledge in its artificially restricted significance, was irresistibly drawn back to the older philosophy whence it had been originally borrowed; then, just as his master had given an ethical application to science, so did he, travelling over the same ground in an opposite direction, extend the theory of ethics far beyond its legitimate range, until a principle which seemed to have no meaning, except in reference to human conduct, became the abstract bond of union between all reality and all thought.A distinct parallelism may be traced in the lines of evolution along which we have accompanied our two opposing schools. While the Academicians were coming over to the Stoic theory of cognition, the Stoics themselves were moving in the same general direction, and seeking for an external reality more in consonance with their notions of certainty than the philosophy of their first teachers could supply. For, as originally constituted, Stoicism included a large element of scepticism, which must often have laid its advocates open to the charge of inconsistency from those who accepted the same principle in a more undiluted form. The Heracleitean flux adopted by Zeno as the physical basis of his system, was164 much better suited to a sceptical than to a dogmatic philosophy, as the use to which it was put by Protagoras and Plato sufficiently proved; and this was probably the reason why Bothus and Panaetius partially discarded it in favour of a more stable cosmology. The dialectical studies of the school also tended to suggest more difficulties than they could remove. The comprehensive systematisation of Chrysippus, like that of Plato and Aristotle, had for its object the illustration of each topic from every point of view, and especially from the negative as well as from the positive side. The consequence was that his indefatigable erudition had collected a great number of logical puzzles which he had either neglected or found himself unable to solve. There would, therefore, be a growing inclination to substitute a literary and rhetorical for a logical training: and as we shall presently see, there was an extraneous influence acting in the same direction. Finally, the rigour of Stoic morality had been strained to such a pitch that its professors were driven to admit the complete ideality of virtue. Their sage had never shown himself on earth, at least within the historical period; and the whole world of human interests being, from the rational point of view, either a delusion or a failure, stood in permanent contradiction to their optimistic theory of Nature. The Sceptics were quite aware of this practical approximation to their own views, and sometimes took advantage of it to turn the tables on their opponents with telling effect. Thus, on the occasion of that philosophical embassy with an account of which the present chapter began, when a noble Roman playfully observed to Carneades, You must think that I am not a Praetor as I am not a sage, and that Rome is neither a city nor a state, the great Sceptic replied, turning to his colleague Diogenes, That is what my Stoic friend here would say.262 And Plutarch, in two sharp attacks on the Stoics, written from the Academic point of view, and probably165 compiled from documents of a much earlier period,263 charges them with outraging common sense by their wholesale practical negations, to at least as great an extent as the Sceptics outraged it by their suspense of judgment. How the ethical system of Stoicism was modified so as to meet these criticisms has been related in a former chapter; and we have just seen how Posidonius, by his partial return to the Platonic psychology, with its division between reason and impulse, contributed to a still further change in the same conciliatory sense.
