Vitalism

Vitalism is the doctrine, often advocated in the past but now rejected by mainstream science, that "living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things". Where vitalism explicitly invokes a vital principle, that element is often referred to as the "vital spark", "energy" or "élan vital", which some equate with the "soul".

Vitalism has a long history in medical philosophies: most traditional healing practices posited that disease results from some imbalance in the vital energies that they thought distinguished living from non-living matter. In the Western tradition founded by Hippocrates, these vital forces were associated with the four temperaments and humours; Eastern traditions posited similar forces such as qi and prana. While it is sometimes contrasted to reductionism, it is opposed by physicalism.