According to Santayana and Russell, Bergson projected false claims onto the aspirations of scientific method, claims which Bergson needed to make in order to justify his prior moral commitment to freedom. Russell takes particular exception to Bergson's understanding of number in chapter two of "Time and Free-will". According to Russell, Bergson uses an outmoded spatial metaphor ("extended images") to describe the nature of mathematics as well as logic in general. "Bergson only succeeds in making his theory of number possible by confusing a particular collection with the number of its terms, and this again with number in general", writes Russell (see "The Philosophy of Bergson" and "A History of Western Philosophy").