The Man of Forty Crowns: I have sometimes a great mind to laugh at all I have been told.

The Geometrician: And a very good mind it is. I advise you to doubt of everything, except that the three angles of a triangle are equal to two right ones, and that triangles which have the same bases and height are equal to one another; or like propositions, as, for example, that two and two make four.

The Man of Forty Crowns: Yes; I hold it very wise to doubt; but I am curious since I have made my fortune and have leisure. I could wish, when my will moves my arm or my leg, to discover the spring, for surely there is one, by which my will moves them. I wonder sometimes why I can lift or lower my eyes, yet cannot move my ears. I think—and I wish I could know a little how—I mean,—there, to have my thought palpable to me, to touch it, as it were. That would surely be very curious. I want to find out whether I think from myself, or whether it is God that gives me my ideas; whether my soul came into my body at six weeks, or at one day old; how it lodged itself in my brain; whether I think much when in a profound sleep, or in a lethargy. I torture my brains to know how one body impels another. My sensations are no less a wonder to me; I find something divine in them, and especially in pleasure. I have striven sometimes to imagine a new sense, but could never arrive at it. Geometricians know all these things; kindly be so good as to teach me.

The Geometrician: Alas! We are as ignorant as you. Apply to the Sorbonne.