Here's my response to this week's challenge:
Physicalism explains that we are not soul but that we are simply physical: body and brain. There are different types of physicalism when it comes to the mind/body problem, but this challenge is that the mind (mental properties) can ultimately be reduced to the physical.
Let me outline three problems with physicalism. Number one, physicalism can’t account for our mental lives. Physicalism states that the brain is merely a physical thing with physical properties. It has mass, weight, and location. But mental properties are not physical things. When I’m happy or sad, that is a non-physical property. We wouldn’t say that our brain is happy or sad; we say, “I am happy” or “I am sad.” You can’t reduce the mental down to the physical.
Problem number two is that physicalism can’t give you free will. If everything is physical, then cause is physical. So, matter and the laws of nature determine everything. If we are determined by the physical, then free will is an illusion. If you’re going to be a physicalist, then you can’t have free will.
Third problem is physicalism can’t give us an enduring self or identity over time. Twenty years ago, I had a different physical makeup. You’d have to say I was a completely different person twenty years ago. There’s no continuity between the person I was twenty years ago and the person I am today if all we are is physical. If there were no identity through time, that would be a major problem.
I want you to reflect on a question: What are the most important things in life? My wife Erin is one of the most important things in my life. Not just her physical existence, but her love for me. Notice, her love for me is not a physical property of her brain. We can’t crack her skull open, look inside, and find her love for me in her brain. Her love for me is not a physical property of the brain, and it’s not something that can be measured physically.
My son, Jonah, is another thing that’s important to me. Not just his physical existence, but also his happiness. If I want to find out if Jonah’s happy, I won’t be able to find it in his brain as a physical property, I’ll find it in his soul. His happiness is not a physical property of him or his brain.
When you think about the most important things in life, you think about things like happiness, love, friendship, liberty, and freedom. Notice that none of the things on that list are physical. These mental properties can’t be explained by physicalism. If physicalism can’t do the explaining, there must be a better explanation.
The better explanation is dualism. It’s the idea that human beings are composites of body, brain, and soul. The physical and the non-physical. It’s our soul that can account for mental properties, sensations, and desires. There’s an interaction between body and soul. That’s why drugs someone takes for anxiety and depression can work and help someone feel better because there’s an interaction between body and soul. Dualism, body and soul, best accounts for our experience as human beings.