state of perfect assurance, step by step he saw it recede before him. He looked for certitude in the perceptions of the senses, with the result that he could no longer trust his senses. Sight, the most powerful of the faculties of sense, for example, led him to the perception of an immovable shadow on the sun and an hour afterwards this shadow was gone. Sight showed him a star which is very small, and geometry made him recognise it to be greater than the earth. Then he turned to the first principles of reason; but the perception of the senses took its revenge in saying to him: 'Previously you believed in me and you abandoned me when this judge reason presented itself. If this judge had remained hidden you would have continued to believe in me. Who can tell you that beyond the reason. there is no other judge, which if it made itself evident, would convict reason of falsehood? That is a movement of thought which is dramatic enough, though perhaps
