Materialism, a term coined, but not founded, by Rene Descartes is a common philosophical belief among modern academic philosophers today. It refers to a school of thought in which physics imposes logical restraints on the concepts of matter (mass and energy). It determines that there is nothing that exists outside the restraints of the "laws of nature," and contains a metaphysical view that there is only one type substance in the universe, physical or material. There is no accounting of spirit or consciousness and a materialist denies the existence of any supernatural, ephemeral, and esoteric things. René Descartes (1596-1650), a French philosopher, is largely associated with the materialist point of view, and largely discussed the relationship between materialism and substance dualism. To define the difference and separation between mind and body, Descartes constructed the "knowledge argument . Descartes, in Meditations, questions the type of thing he is. To answer this, Descartes considers what it takes for him as an entity to exist. For example, if a tricycle were to lose a wheel, it would no longer be a tricycle. By using the "evil demon  supposition in which one entertains the possibility that one's physical experiences are actually hallucinations caused by an evil demon, Descartes claims that he can rightfully doubt the existence of his body at all. What he states he cannot doubt, is the existence of his mind, for it is with his mind that he thinks of these things. He goes further to say that the mind is one whoe, separate identity from the body because when one thinks, Descartes supposes that one thinks with their entire mind; that it is indivisible. In Descartes' The Description of the Human Body, he describes the body as possessing the qualities of a machine. He makes a distinction between the physical body and the immaterial mind, though, and defines the mind as a non-material "substance  that does not follow the