The Principles of Science

The mathematician, economist, and logician William Stanley Jevons (1835–1882) is perhaps now best known for having been one of the founding figures in the development of the theory of utility in economics. But for our purposes, he was also a keen analyst of reasoning – his presentations of deductive logic, of induction, and of scientific reasoning were among the most important published in English during this period. In this work, Jevons also opened up a much more fundamental role for probability in the justification of induction, which is the subject of the excerpt here. For Jevons, measures of quantities are always estimates of their true values; induction is the result of the application of probability…