Rene' Descartes, a French philosopher, mathematician and writer has been dubbed the father of modern and Western philosophy. He is very well known for his philosophical statement "Cogito ergo sum" meaning I think, therefore I am. He was a philosopher who very well formed the mind body problem. Dualism- that is the claim that the mind and body are two entirely separate categories- is often associated with Descartes. It claims that neither the mind nor the body can be equated to the other in any way. They are capable of existing apart. This stands in contrast to philosophical monism which views the mind and the body as ultimately the same thing. Descartes has reason in this claim that the mind and body are distinct because they are logically distinct therefore must be ontologically distinct, the body is divisible however the mind is indivisible and the body's physical state is observable but the mind's thoughts are not observable. .
The mind and the body are logically two different things and are not equal to each other. In order to be identical, all properties must be shared and identical. The properties belonging to the mind and the body are different and therefore the mind cannot be equal to the brain. Descartes understands the body as follows: " whatever can be determined by a certain shape, comprised in a certain location, whatever so fills a certain space as to exclude it from any other body, whatever can be apprehended by touch, sight, hearing, taste or smell and whatever can be moved in various ways " [Meditation II] For example, the material does have extension in space. A stone evidently takes up space. The mental does not have extension in space. One's thought's cannot take up space like a stone does. Conversely, the mental is capable of thinking and having thought processes. The material cannot do this. A stone cannot think and have thought processes like the mind does. The mind is a thinking thing and lacks the attributes that physical objects possess such as shape, size and location.