Arbitrary Marks

A few weeks ago, I picked up Jaegwon Kim’s slim volume Phyicalism, or Something Near Enough and have finished his first chapter, an overview of the philosophical situation.

He calls the two problems of mental causation and consciousness Weltknoten, or a “world-knot” which philosophers haven’t been able to unravel yet. In a nutshell, the problem is that several key claims which seem to be necessary to hold are contradictory:

1. Physical causal closure
2. Causal exclusion
3. Mind-body supervenience
4. Mind-body property dualism

Here’s what they are, in turn, because the discussion this summer on Arbitrary Marks will revolve around these ideas as well as conceptions of causation in itself (not merely in relationship to the mind).

1. Physical causal closure simply means that we accept that physical events have physical causes. It doesn’t mean, necessarily, that there are only physical things, but non-physical events would have non-physical causes.

2. Causal exclusion is a way of avoiding the problem of overdetermination. Say a physical event has a sufficient cause (like ice melting is caused by the temperature dropping). Then nothing else, distinct from the temperature dropping, at the same time can be a cause of the same event.

3. Mind-body supervenience is typically accepted by philosophers of mind, and is the unextraordinary claim that our mental processes are dependent entirely upon our physical processes. Basic neurology, as shown by the famous story of Phineas Gage, demonstrates this.

4. Mind-body property dualism then claims that although my mental properties supervene on my bodily processes (thoughts supervene on brain states), they aren’t reducible to the bodily properties. In other words, my thought which occurs at a specific time due to brain processes has its own mental properties which are described by psychology, reference to intentions, etc. They cannot be described by referring to the neurons in my brain.

What’s the problem? Taken separately, these four statements are perfectly legitimate. Unfortunately, putting them together puts us in a difficult position.

The Problem of Mental Causation

Suppose I have a thought (we’ll call it M) and that causes me to have a memory (M*). That’s not an unusual occurrence to us as it happens all the time. On (3) above, my thought M exists because it supervenes on some physical properties which we’ll call P. And M* exists, likewise, due to properties P*.

What is the cause of M*, then? Is it M? If so, then we must include P* as the cause, too, because without P*, we wouldn’t have M*; one generates the other. But look at (2) - we can’t have overdetermination, or at least we want to avoid it if possible.

So, we can refine our story and say that M causes P* which causes M*. There’s a single arrow of causality: M –> P* –> M* and no overdetermination.

Unfortunately, M only causes P* in virtue of P! So it seems that we have to choose M or P, the mental or the physical, as causes. But we don’t want to say that our mental life is devoid of causality because that brings us to a reductionistic picture which we’re avoiding in (4).

But, further, Kim thinks that even such reduction (which might possibly solve our problem if we can accept it and replace #4) isn’t possible because we can’t characterize qualia merely by their function like we might be able to with cognition and other mental states. Similarly, consciousness doesn’t seem to be reducible in this way, so that problem also remain–the two are tangled together at the question of functional reduction.

As Kim puts it, “What stands in the way of solving the problem of mental causation is consciousness. And what stands in the way of solving the problem of consciousness is the impossibility of interpreting or defining it in terms of its causal relations to physical/biological properties.”

So: stay tuned for the next five chapters of Physicalism and, as I progress with the Vigraha*, some constructive reflection on how the two debates may be interrelated.

Jaegwon Kim, Physicalism or Something Near Enough, (Princeton: Princeton UP), 2005.

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