I shall endeavor to show that induction is really the inverse process of deduction. - William Stanley Jevons

What capital I give for the spade merely replaces what the manufacturer had already invested in the expectation that the spade would be needed.

When quite young I can remember I had no thought or wish of surpassing others. I was rather taken with a liking of little arts and bits of learning. My mother carefully fostered a liking for botany, giving me a small microscope and many books, which I yet have. Strange as it may seem, I now believe that botany and the natural system, by exercising discrimination of kinds, is the best of logical exercises. What I may do in logic is perhaps derived from that early attention to botany.

Logic is not only an exact science, but is the most simple and elementary of all sciences; it ought therefore undoubtedly to find some place in every course of education.