I used to think I should like to be a bookbinder or bookseller it seemed to me a most delightful trade and I wished or thought of nothing better. Mor… - William Stanley Jevons

My principal work now lies in tracing out the exact nature and conditions of utility. It seems strange indeed that economists have not bestowed more minute attention on a subject which doubtless furnishes the true key to the problems of economics.

In this work I have attempted to treat economy as a calculus of pleasure and pain, and have sketched out,almost irrespective of previous opinions, the form which the science,as it seems to me, must ultimately take.

The laws of thought are natural laws with which we have no power to interfere, and which are of course not to be in any way confused with the artificial laws of a country, which are invented by men and can be altered by them. Every science is occupied in detecting and describing the natural laws which are inflexibly observed by the objects treated in the Science.