The purpose of this work is to philosophically analyze the Cartesian dualism and the problem of mind and body relationship according to Rene Descartes. The mind–body problem is a philosophical problem concerning the relationship between the human mind and body, although it can also concern animal minds, if any, and animal bodies. It is distinct from the question how mind and body can causally interact, since that question presupposes an interactionist account of mind-body relations. The problem was addressed by René Descartes in the 17th century, resulting in Cartesian dualism. Dualism maintains a rigid distinction between the realms of mind and matter. Descartes thus comes to is that he possesses mind, his thinking being, as distinct from his body, extended essence. This means that there are two aspects of man, corresponding to two substances: spiritual substance, (mind), which has thinking as its essence and material substance (body), with extension as its essence. Mind and body are therefore, two kinds of substance, each of which is distinctly different, and can exist independent of each other. In conclusion, hence, even though there have been many arguments in support and against the mind-body problem, at best, this study can only see the interaction of the two distinct substances as probable. The fact is that if the reductionist position of scientists is accepted, that means only the physical, corporeal things such as the brain, body, etc. exist. It also means that the so-called thinking activities, as observed by Descartes are solely carried out by the brain. As the scientists would hold, if the brain dies, the entire thought-system stops working; as a result, the brain therefore is the self.