Vitalism is an idea that living organisms are differentiated from the non-living by the presence of forces, properties or powers including those which may not be physical or chemical. Varied forms of vitalist theories were held in former times and they are now considered pseudoscientific concepts. 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 belonging to the mechanistic school 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now consider vitalism in this sense to have been refuted by empirical evidence, and hence regard it either as a superseded scientific theory, or as a pseudoscience since the mid-20th century.
Vitalism has a long history in medical philosophies: many traditional healing practices posited that disease results from some imbalance in vital forces.
