First published in 2002. Routledge is an imprint of Taylor & Francis, an informa company.

All natural sciences follow a method which may be called the "analytic method." In order to become a science, psychology must adopt this method: for it is the method which makes the science. It might be objected that the material makes the science, but that is not the case: the science is essentially the method, and the material only the particular limitation which it is convenient to adopt for practical purposes. It is clear that the psychologist must use an analytic method as much as possible, if he is to produce a science; and also that he must find for himself the right units into which...