The "indivisibility argument" for dualism was phrased by Descartes as follows:is a great difference between a mind and a body, because the body, by its very nature, is something divisible, whereas the mind is plainly indivisible…insofar as I am only a thing that thinks, I cannot distinguish any parts in me.… Although the whole mind seems to be united to the whole body, nevertheless, were a foot or an arm or any other bodily part amputated, I know that nothing would be taken away from the mind…The argument relies upon Leibniz' principle of the identity of indiscernibles, which states that two things are the same if and only if they share all their properties. A counterargument is the idea that matter is not infinitely divisible, and thus that the mind could be identified with material things that cannot be divided, or potentially Leibnizian monads.