James Henry Leuba (1867-1946) was an Americanpsychologist, best known for his contributions to the psychology of religion. His work in this area is marked by a reductionistic tendency to explain mysticism and other religious experiences in physiological terms. Philosophically, his position may be described as naturalism. His work points to similarities between religious mysticism and yoga or drug-induced mysticism; he does accept differences between these in terms of moral motivation and to what uses mysticism is put. He argued for a naturalistic treatment of religion, which he considered to be necessary if religious psychology was to be looked at scientifically.