In philosophy, the position that life in all its forms cannot be explained adequately or completely in either chemical or physical terms. It assumes there must be some ‘higher’ or ‘other’ dimension as well, such as the ‘soul’ or Bergson, Henri’s notion of the élan vital. Vitalist principles have been at the heart of medical thinking since at least the time of the ancient Egyptians, but in the latter half of the twentieth century fell into decline as scientists came to believe that the chemical and physical accounts of life were sufficient and anything beyond that was an unnecessary abstraction, or worse, obfuscation.