It just doesn’t seem possible that every characteristic of the brain (matter) can be a property of the mind (and vice versa). Consider:
- Does the mind—or events within it—weigh anything? How many grams does a mental event weigh?
- While we can dye the brain red or blue, the mind—or particular thoughts—cannot be dyed. I may imagine a color (say, brown), but that does not mean that my brain is therefore the color of brown.
- I can think about pain without feeling pain. My thoughts about pain don’t necessarily bring me pain. Or I can think of some given pain experience without entertaining any idea of the accompanying material or physical activity. So clearly there is a lack of identity between these psychological and physical properties.
- Thoughts can’t be located in space. Is my thought about eating Ben & Jerry’s New York Super Fudge Chunk ice cream nearer to my left ear than my right?
- While beliefs can be true or false, matter cannot be. Matter just is; it’s not true or false. As C. S. Lewis observed, “To talk about one bit of matter being true of another seems to me to be nonsense.” So belief can’t just be a brain state and nothing more.
— Paul Copan, from “How Do You Know You’re Not Wrong”, kindle location 1029