The Causal and the Mental

The topic of mental causation in contemporary philosophy of mind is a vexed one, constrained by only one rule: avoid epiphenomenalism. There is a deep sense that there simply has to be mental causation of some kind – our psychological/mental states – beliefs, desires, intentions – must, in some way, have some causal influence over or on our behaviour. Whatever else may or may not be the case, this is something we have to have. This is the data we have to explain.

There are, generally, two broad ways to approach the issue of mental causation (MC): either the mind/body are two distinct substances (substance dualism, SD) or they are not (let’s call this broad physicalism, BP – and we’ll assume that an account of BP aims to be non-reductive). This lets us divide up the problems of MC a bit more easily:

On SD, if the mind and body are two distinct substances, one material and one immaterial, the issue becomes just how to explain, describe and define the causal relation between the mind and body. Simply put, what is the nature of the causal relation here? The objections here are well known: how could an immaterial substance be in any kind of causal relation with a material substance? It just seems odd that such a relation exists – and if the mind is independent from the brain, as SD claims, then what do we make of the cases where, say, a blow to the head (or the aftereffects of brain trauma, such as agnosia) disrupts consciousness or conscious processes? The opposite would seem like the natural conclusion – if the mind truly is independent from the brain, then consciousness should continue uninterrupted by any kind of physical disturbance.

William Hasker identifies a related issue in his book ‘The Emergent Self’:

‘Phillip Quinn doubts this: “I’d be willing to bet that we will learn from neuroscience…that thus processing of visual information goes on in the brain. And if a Cartesian mind requires as input processed rather than unprocessed visual information in order to perform such tasks as identifying faces and reading facial expressions, it will come as no surprise that it can’t perform that it can’t perform such tasks if its damaged brain can’t provide it with the processed visual information it requires as inputs.”

The problem with this lies in the strong probability that, as neuroscience progresses, more and more of our “advanced” mental processes will be found to be associated with, and dependent upon, specific brain processes. When that happens, Quinn’s strategy would lead us to a view of the conscious mind as essentially a passive spectator, enjoying awareness but contributing little or nothing of its own to those results.’ (p. 155)

Epiphenomenalism by any other name…

What of our other position, Broad Physicalism? Here the issue takes a similar form: how to account mental causation with only material substance (only the physical) without lapsing into epiphenomenalism. Immediately an objection jumps out at us: if, as one would think is necessary for BP, physical explanation is necessary and sufficient, what role is there for the mental? It seems as though epiphenomenalism is waiting to pounce.

There’s a few possible solutions here. Supervenient causation is one of those solutions, but it’s difficult to find an acceptable version of it that doesn’t end up becoming reductive. Type-identity theories have more or less gone by the wayside, replaced with a more hopeful alternative, token-identity theories, where mental-event tokens are identified with physical-event tokens, which avoids the problem of multiple realization that plagued type-identity theories – and if. Here the problem becomes one of identification of events, and Donald Davidson supplied an account: an event is identical to another event if their causes and effects are identical. This ties in to his theory of anamolous monism: mental states are not governed by any strict laws, and thus cannot be reduced to physical states or given a pure physical explanation, since physical explanation involves strict laws. This position recognizes that mental events are physical events without reducing them to only physical events.

The payoff here is that if mental events can be identified with brain events, then it is easy to see how there is mental causation. Hasker notes a difficulty here, though, with Davidson’s identity criterion:

‘Put briefly, the theory is circular: causal relations are identified by the events they relate, and events are identified by the causal relations in which they stand. Clearly, one or the other has to be identified in some other way, so as to enable us to break into this closed circle. And since there seems to be no prospect of identifying causal relations except as relations between events, it seems that it will have to be the events themselves which are characterized in some other way.’ (‘The Emergent Self’, p. 38)

Jaegwon Kim notes another difficulty with Davidson’s theory of anamolous monism:

‘Davidson’s anamolous monism fails to do full justice to psychophysical causation in which the mental qua mental has any real role to play. Consider Davidson’s account: whether or not a given event has a mental description seems irrelevant to what causal relations it enters to. Its causal powers are wholly determined by the physical description or characteristic that holds for it; for it is under its physical description that it may be susbsumed under a causal law.’

Kim proposes a different theory of identification: events are exemplifications by substances of properties at a time. This view is well-known and seems to be the strongest account of token-identity, but it suffers from the difficulty not of being circular but of multiplying events beyond reason. If Kim’s theory is true, then, as the well-known critique goes, no stabbing is ever a killing, since the stabbing and killing are two different properties. Simply put, Kim cannot identify events with each other because they are not identical. Brutus stabbing Cesear is not the same as Brutus killing Cesear. The payoff here, as noted by Davidson, is that Kim cannot identify brain events with mental events, which seems to be a significant weakness for a token-identity theory.

Where does this meandering leave us, then? On SD, we have the interaction problem: how do two substances, one material and the other not, interact? On BP, it seems that there is serious difficulty giving an account of mental causation that is actually an account of mental causation. My first reaction is, noting the serious difficulties with thinking of the mind/body relation in terms of causal relations, to think of the mind/body relation in non-causal terms. This is the Aristotelian position of hylomorphic dualism, which, for the sake of sanity I will leave for another day. But the takeaway, I think, is this: perhaps the mind/body relation needs to be thought of in non-causal terms.

Conceptual Confusions and Philosophy of Mind

Of all the conceptually confused areas in philosophy, philosophy of mind is probably the most confused. Think of, for example, mental causation, or the debates on the relation of brain states to mental states, or the causal relation of neurons to thoughts, things along those lines. The confusion, like all conceptual confusions, is a simple one.

Suppose one performs a scan of a brain and observes the patterns of neurons when a certain cognitive action, like thinking of a certain thing, happens – or observe certain areas of the brain lighting up when a certain cognitive action is undertaken. In short, the physiological processes that, more or less, make thought happen. This is a normal observation made every day in laboratories across the globe – the confusion arises when it is assumed that what is observed is mental causation (brain states cause mental states, or something of the sort).

Empirically, what is observed is not mental causation but mental correlation – as I’ve pointed out before, causality is a metaphysical, and not an empirical, category. Any notion of causation takes one, implicitly if not explicitly, into the realm of philosophy. If one supposes that all that is observed is all that there is, one has crossed from science into philosophy – whether or not it is done well is another story entirely.

(As a late edit, I’ll add that mental causation is more varied than what I listed here – for example, epiphenomenalism, which denies the mental any causal power – mental states are caused by brain states, but brain states are not causally influenced by mental states – is a big part of the philosophy of mind debates)

This shows, again, how intimate the connection between science and metaphysics is. Think of an intricate braid made of two different strands of rope. While they are two distinct things, when they are intertwined correctly, they form a strong, intimate bond, as opposed to being tangled together in a lump, which serves only to prevent it from being used properly.

While of a slightly different nature than the causal confusion above, it’s easy to see how other confusions arise – for example, that neuroscience has shown that free will is an illusion. This again is simply a muddle of confused thinking – certainly brain science has a lot to tell us about the mechanical/physiological aspect of human volition (it has, and will continue to, inform us more and more of the mechanical, but not mechanistic, workings of the brain), but it has very little, if anything, to say about human freedom seen as a whole, and not merely seen as volition (which has very little part to play in a full account of freedom).

Such are the perils of conceptual confusions.