Psychology: science that studies behaviour and the physiological and cognitive processes that underlie it, and it is the profession that applies the accumulated knowledge of this science to practical problems. Based on observable facts/ data and well described methods. Psyche: greek for soul, spirit or mind logos: study of the subject. Aristotle (384-322): naturalist and placed humans at top of natural scale of intelligence. Theory of memory: memories are result of three principles of association: similarity, contrast and contiguity. St thomas aquinas (1224-1274) - tried to reconcile christianity with aristotelian philosophy. Returned to the idea that humans were separate from other creatures. Rene decartes- monism (separate mind and body), soul being province of god . Memory, perception dreaming- properties of the body, thus open to being understood in naturalistic terms. Leg muscles retract. (fire is reflected in the leg withdrawal= reflex) The mind reasons about the world and is separate from the mechanical or reflexive body.