From guest blogger, Shiying.
On a class about life after death, we discussed several arguments for Dualism proposed by Descartes. Dualism views are views about the relationship between the body and the mind that claim that the mind and the body, or the mental and the physical are both real and neither can be assimilated to the other. Here is one of the arguments:
(1) My mind is essentially thinking.
(2) My body isn’t essentially thinking.
(3) Thus, my mind is not my body.
In order to examine this argument, I want to first look at the second premise which says
that bodies are not essentially thinking. One objection non-dualists can raise about this premise is to say that a well functioning body is essentially thinking. In reply to this objection, dualists use the thought experiment of the philosophical zombie to prove that a well functioning body is not essentially thinking. A philosophical zombie is a hypothetical being that is indistinguishable from a normal human being except that it lacks conscious experience. There are several types of philosophical zombies including behavioral zombies, neurological zombies and soulless zombies. But we can come up with a type of zombie that has a well functioning body, including the brain, but is not thinking, because it does not have conscious experience. There are some disputes about whether the zombies are metaphysically possible. Some argues that logical possibility does not entail metaphysical possibility. Thus, the philosophical zombies are either only logically possible or metaphysically possible.
Now let’s look at the first premise, saying the mind is essentially thinking. I think whether this statement is true largely depends on the definitions of the “mind”, and of “thinking”. If we use definitions of the “mind” and “thinking” so that the mind is not essentially thinking, then premise is not true and the argument fails. However, if we use definitions of the “mind” and “thinking” that enables the mind to be essentially thinking, then it is logically impossible for the mind to stop thinking. Therefore, the difference between the mind and the body is that it is logically impossible for the mind to stop thinking, but it is logically possible for the body to stop thinking, or it is metaphysically possible for the body to stop thinking. These are different properties and if Leibniz’s Law applies to these properties, the mind and the body are distinct entities that cannot be assimilated to each other. However, I think there can be disputes about whether these properties are important properties that we really care about and if Leibniz’s Law can be applied to these properties.