In this essay, I will be explaining whether Descartes has good arguments to support his dualism or not. In the first section, I will outline the kind of Dualism of mind and body that Descartes endorsed and I will also explain Leibniz’s Law as it is used for the arguments for dualism, which I will also explain in a later section. In the second section, I will explain the strengths and weaknesses of Descartes’s Dualism. In the third section, I will explain Descartes’s arguments for his Dualism. In the fourth and final section, using the strengths, weaknesses, and Descartes’s arguments, I will assess whether Descartes does have good arguments to support his dualism or not.
Descartes’s dualism is that the body and brain are physical objects, while the mind is a nonphysical object and it is different from the body and the physical parts of the body. Even though the mind and body are distinct from each other, Descartes did not refuse the fact that there are causal interactions between the two, for example, if a person were to get stung by a bee, a painful feeling would be caused in the mind; another example would be that if someone were playing soccer, the person would have a mental decision to move his/her legs in order to run and kick the soccer ball, the decision would cause the person’s legs to move which would allow the person to run and kick the ball. Leibniz’s Law is the idea where if two objects were identical, then the two objects share all the same properties, otherwise, if there was just one property that either of the objects lacks, then the two objects aren’t identical, they would be distinct from each other.
A strength of dualism is that it stays consistent with the idea that the body and mind are two different things, as we have the ability to think or have thoughts or believe, using our minds, but we are not able to think, using our brain or body, and it isn’t possible to somehow physically interact with the brain or body to cause ourselves to think or believe, neither is it possible to look into our brains to see what we are thinking. A weakness of dualism is its inability to answer the question of how is there a causal connection between the mind and the brain, since Princess Elizabeth of Bohemia asked Descartes how the “soul of a man” can cause the body to “produce a voluntary action”, to which Descartes answered that the causal connection between the two is unexplainable.
The first argument for dualism that Descartes has made is “The Indubitable Existence Argument”. According to the argument, you cannot doubt that you have a mind, because if you try to doubt that, you’ll realize that you’re having a thought that you don’t have a mind, which wouldn’t make sense because if you didn’t have a mind, then you wouldn’t be able to have a thought, therefore you must accept that you do have a mind. Even though you can’t doubt that you have a mind, the argument says that you can doubt that you have a body, which leads to the idea that the mind has a property that the body does not have, which follows Leibniz’s Law and this leads to the conclusion that the body and mind aren’t identical. Descartes’s second argument for dualism is “The Divisibility Argument” where physical things or the body have spatial properties, but the mind doesn’t have special properties; also, the body has spatial location, meaning that it has the ability to take up physical space, while the mind doesn’t have spatial location, meaning that it doesn’t have the ability to take up physical space, and this follows Leibniz’s Law, as the body has a property that the mind doesn’t have, therefore the mind and body are different from each other. Descartes also has a third argument that states that a person can imagine that their mind can exist without their body, and because of this, the mind is able to exist without the body and if we were to suppose that the mind is the brain, then without a person’s body, the mind of the person is not able to exist.
Using the strength and weakness and the arguments, the weakness leaves a big hole to be filled as dualism cannot explain the causal connection between the body and mind, despite Descartes not denying the fact that there are causal connections between the body and the mind. One problem with the first argument from Descartes can be noticed using the Superman/Clark Kent example by Elliot Sober, where Lois Lane doesn’t want to marry Clark Kent, but she wants to marry Superman, and because of this, according to Leibniz’s Law, Superman has a property that Clark Kent doesn’t have, therefore they are not identical, but this does not make sense as there is no such property being described and Superman and Clark Kent would share all their properties as they are the same person; this all leads back to the first argument where it is stated that you cannot doubt that you have a mind, but you can doubt that you have a body, but that doesn’t mean that your body has a property that your mind lacks. Also, one problem with the second argument is that, according to Elliot Sober, the ideas stated in the second argument are “unfamiliar” since they’re quite different from what we believe in; Sober uses the example of water, where before it was discovered that water was made from particles, if you were to tell someone that water was made out of tiny particles, people would find that strange, unbelievable, and maybe would call you crazy, but this does not go against the fact that water is indeed made up of particles.