2. Consider the following argument by Princess Elisabeth against Cartesian Substance Dualism:

1.Only a physical impulse can cause motion.
2.Anything immaterial cannot cause a physical impulse, and hence, cannot cause motion.
3.The mind sometimes causes motion in matter.
4.Therefore, the mind cannot be immaterial.

*note: Elisabeth and Descartes sometimes use “soul” as a stand in for the “mind”.

Do you think this is a sound argument? If so, explain why. If not, which premise(s) do you think is false/implausible, and why?

Question

2. Consider the following argument by Princess Elisabeth against Cartesian Substance Dualism:

1.Only a physical impulse can cause motion.
2.Anything immaterial cannot cause a physical impulse, and hence, cannot cause motion.
3.The mind sometimes causes motion in matter.
4.Therefore, the mind cannot be immaterial.

*note:  Elisabeth and Descartes sometimes use “soul” as a stand in for the “mind”.

Do you think this is a sound argument? If so, explain why. If not, which premise(s) do you think is false/implausible, and why?

Ask a Philosopher · Accepted Answer

Firstly, Princess Elisabeth's argument against my substance dualism does seem on the surface to hold some validity. Motion in the physical world certainly requires a physical impulse, so if the mind - or as she often refers to it, the soul - causes motion in matter, it seems to suggest that the mind cannot be immaterial. However, I would argue that this logic is flawed in several ways.

Firstly, it assumes that the mind or soul is separate from the body and has the ability to cause motion in matter. I myself have never claimed that the mind exists independently of the brain or body, but rather that it is intimately connected with them. Therefore, it is entirely possible that the mind is not directly causing motion in matter, but rather that the activity of the brain is.

Secondly, even if we were to assume that the mind is causing motion in matter, it does not necessarily follow that the mind must be physical. After all, we know that thoughts and emotions have an effect on the body - just think of how your heart rate increases when you're scared or excited. Yet no one would argue that thoughts and emotions are physical entities.

Finally, Princess Elisabeth's argument seems to rest on a physicalist assumption that all causes must be physical in nature. However, this is far from a proven fact and is in fact a highly debated topic in philosophy. It may well be that there are non-physical causes that can impact the physical world.

So, in conclusion, while Princess Elisabeth's argument may seem convincing at first glance, upon closer examination it is not nearly as sound as she believes it to be. And let's be real, who would want to give up the idea of the soul anyway? It's so much more romantic and exciting than the idea that we're just bags of bones and flesh!"