The mind and body are composed of substances, which have incompatible qualities. The essence of the mind is non-physical thought whilst the essence of the body is physical. In applying Leibniz Law, they cannot be one and the same thing. DESCARTES further argues, using Leibniz Law, that whilst a physical thing can be divided into sections or parts, something that has a non-physical location cannot be divided. The soul and mind, therefore, is indivisible as well as immaterial.