It was by that somewhat slow and circuitous process, the negation of a negation, that spiritualism was finally established. The shadows of doubt gathered still more thickly around futurity before another attempt could be made to remove them. For the scepticism of the Humanists and the ethical dialectic of Socrates, if they tended to weaken the dogmatic materialism of physical philosophy, were at first not more favourable to the new faith which that philosophy had suddenly eclipsed. For the one rejected every kind of supernaturalism; and the other did not attempt to go behind what had been directly revealed by the gods, or was discoverable from an examination of their handiwork. Nevertheless, the new enquiries, with their exclusively subjective direction, paved the way for a return to the religious development previously in progress. By leading men to think of mind as, above all, a principle of knowledge and deliberate action, they altogether freed it from those material associations which brought it under the laws of external Nature, where every finite existence was destined, sooner or later, to be reabsorbed and to disappear. The position was completely reversed when Nature was, as it were, brought up before the bar of Mind to have her constitution determined or her very existence denied by that supreme tribunal. If the subjective idealism of Protagoras and Gorgias made for spiritualism, so also did the teleological religion of Socrates. It was impossible to assert the priority and superiority of mind to matter more strongly than by teaching that a designing intelligence had created the whole visible universe for the exclusive enjoyment of man. The infinite without was in its turn absorbed by the infinite within. Finally, the logical method of Socrates contained in itself the germs of a still subtler spiritualism which Plato now proceeded to work out.