Scientific psychology has historical roots in both mental philosophy and physiology.
When it first appeared, it was even commonly referred to as the new physiological psychology. In England, in the period between 1850 and 1875, a small group of physicians developed what was, in effect, a school of physiological psychology built around just these principles. The primary assumptions of the group were that biology and medicine, not metaphysics, would provide the necessary foundation for psychology, that mind must be understood in its relationship to nervous function, and that mind and body exist in mutual inter-action. At the same time, however, there was also recognition that mind and body are not identical and that mind plays an active, determining role in human affairs. In 1852, Carpenter incorporated a large section on physiological psychology into the fourth edition of what was, at the time, the leading English language text on human physiology.