Assess Substance Dualism

Assess Substance Dualism

Another argument that Descartes put forward for dualism was the argument from doubt. This argument resulted from Descartes' effort to try and bring everything he knew into doubt in an attempt to discover what truths are certain and can serve as a foundation of knowledge. The argument from doubt can essentially be set out as follows: 1) I can doubt that my body exists. 2) I cannot doubt that I exist. 3) Therefore, I must be different and distinct from my body. Through his three waves of doubt he is able to prove the first two premises of the argument. He then goes on to argue that if he is different and distinct from his body, he must be non-bodily in nature, namely, something lacking extension and all physical features. Also, due to the fact he cannot logically deny or doubt his own consciousness, one true property which distinctly belongs to him as an incorporeal substance is his thoughts and consciousness. However, the question arises on whether the argument can establish at all whether Descartes is an entity distinct from his body. The argument relies on a principle known as Leibniz' law, according to which, if properties of a thing A and a thing B are one and the same, then all the properties of A must also have the same properties as B. Hence, if there is at least one property or feature which A and B do not share, then they must numerically be different things from each other.

Nonetheless, there are certain exceptions to Leibniz' Law. One response is that it can be parodied; 1) Lois Lane knows that the reporter with whom she works is Clark Kent. 2) She does not know that the reporter with whom she works is Superman. Therefore Clark Kent cannot be Superman. Clearly there is something wrong here because an integral part of the stories is that Superman is exactly the same person as Clark Kent. The reason as to why Leibniz' Law fails in this situation can be easily seen. Just because someone (Clark Kent/Superman) is known under one description (by Lois), it does not mean that she is able to recognize him under alternative descriptions of him. Just because she believes, incorrectly, that Clark Kent is not Superman, doesn't prove that Clark Kent and Superman are not the same individual.

Descartes also puts forward yet another argument for dualism, known as the argument from divisibility. The argument is essentially laid out as follows; 1) The body is divisible into parts. The mind is not divisible into parts. Therefore, the mind must be of an entirely different nature from the body, i.e. it must be essentially non-physical. When Descartes considers his own mental states, for example, if he is in pain or feeling angry, he says he can distinguish no parts within himself. Yet, if these are considered as 'states' of a subject, then experiences cannot be split into halves or quarters or any other fraction, because it wouldn't make logical sense. The same would be true for physical states as well, like being fragile, volatile, strong etc. It wouldn't make sense to divide these 'states'.

Substance Dualism cannot however explain the mind-body interaction. One attempt to solve this problem was suggested by Leibniz and known as his psycho-physical parallelism. He said that our mind and bodies had been synchronised with each other by God. The idea is that the mind