Now whilst we readily grant that the instance given in the "_Meno_" does not sustain the inference of Plato that "the boy" had learnt these geometrical truths "in eternity," and that they had simply been brought forward into the view of his consciousness by the "questioning" of Socrates, yet it certainly does prove that _there are ideas or principles in the human reason which are not derived from without--which are anterior to all experience, and for the development of which, experience furnishes the occasion, but is not the origin and source_. By a kind of lofty inspiration, he caught sight of that most important doctrine of modern philosophy, so clearly and logically presented by Kant, _that the Reason is the source of a pure_ à priori _knowledge_--a knowledge native to, and potentially in the mind, antecedent to all experience, and which is simply brought out into the field of consciousness by experience conditions. Around this greatest of all metaphysical truths Plato threw a gorgeous mythic dress, and presented it under the most picturesque imagery.[560] But, when divested of the rich coloring which the glowing imagination of Plato threw over it, it is but a vivid presentation of the cardinal truth that _there are ideas in the mind which have not been derived from without_, and which, therefore, the mind brought with it into the present sphere of being. The validity and value of this fundamental doctrine, even as presented by Plato, is unaffected by any speculations in which he may have indulged, as to the pre-existence of the soul. He simply regarded this doctrine of pre-existence as highly probable--a plausible explanation of the facts. That there are ideas, innate and connatural to the human mind, he clung to as the most vital, most precious, most certain of all truths; and to lead man to the recognitions of these ideas, to bring them within the field of consciousness, was, in his judgment, the great business of philosophy. And this was the grand aim of his _Dialectic_--to elicit, to bring to light the truths which are already in the mind--"a μαίευσις" a kind of intellectual midwifery[561]--a delivering of the mind of the ideas with which it was pregnant. [Footnote 560: As in the "Phædo," §§ 48-57; "Phædrus," §§ 52-64; "Republic," bk. x.] [Footnote 561: "Theætetus," §§ 17-20.]