He is not unwilling to admit the sensible world into his scheme of truth.

Nor does he assert in the Republic the involuntariness of vice, which is maintained by him in the Timaeus, Sophist, and Laws (Protag., Apol., Gorg.).

Nor do the so-called Platonic ideas recovered from a former state of existence affect his theory of mental improvement.

Still we observe in him the remains of the old Socratic doctrine, that true knowledge must be elicited from within, and is to be sought for in ideas, not in particulars of sense.

Education, as he says, will implant a principle of intelligence which is better than ten thousand eyes.