Ten-minute philosophy podcast Philosophy Bites has an interview with Prof Tim Crane where he gives an excellent summary of one of the most important topics in contemporary cognitive science – the mind-body problem.
The problem asks how we can reconcile the biological properties of the brain with the subjective mental properties of the mind, because intuitively they seem like quite different things.
One of the most important points often gets lost when people think about this: it is perfectly possible to believe that mind cannot be fully reduced to the function of the brain while still being a materialist – i.e. while thinking that the brain is the only thing that supports the mind and without needing to believe in souls, ghostly spirits, or other non-material things.
How can this be? The key to understanding this is the word ‘reduced’ – i.e. reduction – where one phenomenon is equally well explained by its smaller components.
Importantly, this is a process of fitting theories together. Our idea of heat is equally well explained by our ideas about atoms.
For two things that are understood physically to begin with (e.g. heat and atoms) it works well, but for things that are described using quite different properties, such as thought and the brain, it doesn’t.
Here’s an analogy: when someone plays a recording of a song, everything you experience is carried in the sound waves.
However, you won’t understand why the singer is so in love by looking at the physics of sound, because what is meaningful about the song cannot be fully reduced to physics.
This isn’t a problem of missing detail in the sound. We can measure the sound waves in minute detail. But still, meaning is lost.
The same holds for the mind: even if we could track every single atom in the brain when we have a thought, we might lose meaning when we map the two together.
And if we lose meaning, it means we cannot fully reduce to the mind to the brain. No ghosts, spirits or souls, just a problem of connecting different levels of explanation.
One school of thought, eliminative materialism, argues that this problem highlights the fact that mind-level explanations are inherently unscientific and we should solve the issue by only taking about neuroscience – our subjective experience of the mind is simply wrong and misleading.
Probably the most popular approach at the moment is property dualism – which argues that both mind-level and brain-level explanations may explain how we think and behave but at different levels that may not always be reducible.
This is where there are two type of theories that both attempt to explain something, but in different ways. You can see where, in places, they connect, but they’re not always compatible.
This is different from ‘substance dualism‘, famously invented by Descartes, which says there are two types of substances – the brain, and the soul.
In the recent debates about religion, it’s interesting to see that some people argue that being unable to reduce the mind to the brain is evidence for the God, spirit or soul; while others opposed to religion see any mention of the problem as an indication of support for a non-materialist view.
The key point is that this issue is about how we map theories, not about what sorts of things exist in the universe.
The Philosophy Bites podcast discusses exactly these sorts of issues, particularly with regards to consciousness, perhaps the most well-known example of a problem with mapping the mind to the brain.
Link to Philosophy Bites on the mind-body problem.