Vitalism

Vitalism is a belief that starts from the premise 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", "élan vital" (coined by vitalist Henri Bergson), "vital force", or "vis vitalis", which some equate with the soul. In the 18th and 19th centuries, vitalism was discussed among biologists, between those who felt that the known mechanics of physics would eventually explain the difference between life and non-life and vitalists who argued that the processes of life could not be reduced to a mechanistic process. Vitalist biologists such as Johannes Reinke proposed testable hypotheses meant to show inadequacies with mechanistic explanations, but their experiments failed to provide support for vitalism. Biologists now consider vitalism in this sense to have been refuted by empirical evidence, and hence regard it either as a superseded scientific theory, or, since the mid-20th century, as a pseudoscience. Vitalism has a long history in medical philosophies: many traditional healing practices posited that disease results from some imbalance in vital forces. The notion that bodily functions are due to a vitalistic principle existing in all living creatures has roots going back at least to ancient Egypt. In Greek philosophy, the Milesian school proposed natural explanations deduced from materialism and mechanism. However, by the time of Lucretius, this account was supplemented, (for example, by the unpredictable clinamen of Epicurus), and in Stoic physics, the pneuma assumed the role of logos. Galen believed the lungs draw pneuma from the air, which the blood communicates throughout the body. In Europe, medieval physics was influenced by the idea of pneuma, helping to shape later aether theories. Vitalists included English anatomist Francis Glisson (1597–1677) and the Italian doctor Marcello Malpighi (1628–1694).