How do your thoughts cause your actions?

One of the central questions about the mind is that of mental causation – in other words, do your thoughts cause your actions, and if so, how? Common sense would tell you that your mind is in the driver’s seat – you make the decisions, your body obeys. But is this true and if it isn’t, what then?

Let’s look at how mental causation works if materialism is true. For this post, I’ll assume that materialism entails that your thoughts are encoded in some sort of brain language that is read by your consciousness. So every abstraction your mind produces – such as “dog” or “circle” etc, is stored using brain language and then translated for your consciousness.

A modest example: a tiger appears! You think “I need to run away from this tiger!” This thought is encoded in your brain language and your brain sends a signal to the rest of your body telling it to run away, and off you go. Thus there is a causative link between your brain and the rest of your body. So far so good.

Now, imagine that some crazed neuroscientist has swapped your brain language with its opposite, so that Yes means No and No means Yes. In this circumstance, the physical state of your brain language is unchanged, but your consciousness picks up an entirely different meaning. So instead of “I need to run away from the tiger”, your thought is “I must prepare my tax return” or “I’m zoopdegooging my croodifroods” – or just a complete blank. The logical content of such thoughts is very different, but the underlying physical state is the same. Since the physical state of your thoughts is the same, wouldn’t you run away from the tiger in the same way?

The same applies to anything else you do. You spend hours putting together a budget to decide if you can afford a new house. In the end, you decide to buy. You do this because and only because your brain language is in a certain state. If you had been thinking about football the entire time, or not consciously thinking about anything at all, but the brain language encoding was the same, you still would’ve bought the house.

It’s the physical state of your neurons rather than their logical content that counts. That means that the logical content of your thoughts has nothing to do – and therefore has no causative power over your actions. It’s not that your thoughts are wrong; it’s more that your thoughts are entirely unnecessary,  like a third elbow.

This has consequences. If the logical content of your thoughts is irrelevant, than your thought life is at best a passive observer, an illusion that makes you feel better about yourself but performs no useful function. Your experience of yourself as an active, thinking agent is false.

Also, it follows that rationality cannot possibly have evolved. Natural selection can act on the physical, but how could it act on the content of your thoughts if there is no causative link to your physical brain? For rationality to evolve, there must be a genuine causative link between behaviour and the logical content of your thoughts. So rationality didn’t evolve and must have come into existence some other way.

With natural selection unable to ensure quality, the materialist has two options – either rational thought is a miracle or freakish coincidence, or rational thought is an elaborate fantasy world and we must accept that it is an illusion.

Evolution and immateriality

What if materialism is not true? If the logical content of your thoughts is immaterial and somehow separate to your neurons, does that make it possible for rational thought to evolve? It depends.

If the logical content of your thoughts is a passive observer of your neurons or can bypass your neurons entirely, it will have no causative power and we are back where we started. If the logical content of your thoughts is separate to the structure of your mind and it’s the structure that does the work, there is nothing for the logical content to do and we are back where we started.

For natural selection to operate, the immaterial mind must have real power over the thinking process, rather than being a passive observer. It must be an intrinsic part of your brain as much as its physical aspect is; relying on the physical aspect of mind for its input data and using the physical aspect of mind to implement decisions it makes. Thus we have two-way mental causation – from the body to the mind and vice versa. Finally, the immaterial aspect of mind must be simple – it must be thought alone, rather than thought within a structure.

In conclusion, the concept of immateriality in mind has its advantages. It restores our faith in the theory of evolution by making the evolution of abstract thought possible, and restores our commonsense notion of being active, thinking agents.

To the Western mindset, talk of immateriality in mind seems strange and incomprehensible, but is this a reason to reject it? It is any stranger than what science tells us about quantum mechanics or black holes or many other topics? If science tells us that reality is strange and incomprehensible, on what basis can we insist that philosophy be normal?

It makes no sense to incorporate immateriality into an otherwise unchanged Western mindset; instead it is necessary to demolish the entire thing and rebuild from the ground up. I will discuss two non-materialist philosophies in future posts.

Is this an argument for God’s existence?

Some have used such considerations as an argument for God’s existence, but in my view this is a mistake. The existence of God is a separate issue and should be treated as such.

Further reading

Natural Selection and the Emergence of Mind, by Karl Popper. He argues that natural selection requires two-way causation between mind and body.

The Argument From Reason. Victor Reppert discusses and expands on C.S. Lewis’s critique of materialism and natural selection.

Mental Causation at the Stanford Encyclopaedia Of Philosophy.

The Core Of Mind And Cosmos, by Thomas Nagel. He argues that since mind cannot be physical, “it follows that biological evolution must be more than just a physical process, and the theory of evolution, if it is to explain the existence of conscious life, must become more than just a physical theory”.

Kripke, Ross And The Immaterial Aspect Of Thought (PDF), by Edward Feser. “The late James Ross formulated a simple and powerful argument for the immateriality of our intellectual operations. The gist of the argument is that: “Some thinking (judgment) is determinate in a way no physical process can be. Consequently, such thinking cannot be (wholly) as physical process.”



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