When dealing with the question of the relation between William James's pragmatism and his psychology, the usual answer consists in tracing back the pragmatist epistemology and theory of truth to the functional conception of mind which defines the various intellectual functions as instruments whose purpose is to make action intelligent. The aim of this paper is to outline another relation which often goes unnoticed. My contention is that we can find in James's work a pragmatist conception of psychology itself as a science, which can be expressed in his formula about psychology being a "practical science of mind". "Practical", here, must be understood in two different but complementary meanings. On the one hand, psychology has to become a scientific practice, aiming at the discovery of causal laws and free from all metaphysical speculations (experimentalism). On the other hand, the constitution of psychology as a natural science is the necessary condition for it to have some practical applications, notably to education and medicine. I believe three benefits could be gained by understanding such relationship between pragmatism and psychology. Firstly, this reading enables us to rediscover and cast in a new light a whole series of neglected psychological texts James wrote in the 1890s between the end of his Principles of Psychology (1890) and the beginning of the pragmatist movement (1898). Secondly, it allows us to see the coherence between two sides of his work that are often dissociated and even opposed: his biological conception of mind and his participation in the contested "psychical research". Thirdly at last, it complicates the genealogy of his pragmatism, that is often traced back only to his defense of religious faith (The Will to Believe, 1892), though we see it during the same years arising from his conception of psychology as a natural science.
