CHAPTER IV.
THE NEW PHILOSOPHY.
It is a common prejudice to treat Voltaire as if he had done nothing save write the Pucelle and mock at Habakkuk.

Every serious and instructed student knows better.

Voltaire's popularisation of the philosophy of Newton (1738) was a stimulus of the greatest importance to new thought in France.

In a chapter of this work he had explained with his usual matchless terseness and lucidity Berkeley's theory of vision.
The principle of this theory is, as every one knows, that figures, magnitudes, situations, distances, are not sensations but inferences; they are not the immediate revelations of sight, but the products of association and intellectual construction; they are not directly judged by vision, but by imagination and experience.

If this be so, neither situation, nor distance, nor magnitude, nor figure, would be at once discerned by one born blind, supposing him suddenly to receive sight.
Voltaire then describes the results of the operation performed by Cheselden (1728) on a lad who had been blind from his birth.