Still more unequivocal was the sceptical nihilism expressed by Gorgias: - (I) nothing exists; (2) if anything existed, it would be unknowable; (3) if anything existed and were knowable, the knowledge of it could not be communicated.
These are all knowable things, and yet there is not universal agreement on them.
The new method of definition which Socrates applied to problems of human conduct was extended by Plato to the whole universe of the knowable.
Religion may " feel," like Tennyson's " man in wrath, " and may expatiate in an undefined awe; science alone is to possess the " knowable."
It appears, therefore, that Spencer ultimately describes the Knowable in terms of the mechanical conceptions of matter and motion, and that this must give a materialistic colouring to his philosophy.