Why difference-making mental causation does not save free will

ABSTRACT

Many philosophers take mental causation to be required for free will. But it has also been argued that the most popular view of the nature of mental states, i.e. non-reductive physicalism, excludes the existence of mental causation, due to what is known as the ‘exclusion argument’. In this paper, I discuss the difference-making account of mental causation proposed by [List, C., and Menzies, P. 2017. “My Brain Made Me Do It: The Exclusion Argument Against Free Will, and What’s Wrong with It.” In H. Beebee, C. Hitchcock, & H. Price (eds.), Making a Difference: Essays on the Philosophy of Causation. Oxford Scholarship Online: Oxford University Press], who argue that their account not only solves the problem of causal exclusion but also saves free will. More precisely, they argue that it rebuts what they call ‘the Neurosceptical Argument’, the argument that if actions are caused by neural states and processes unavailable to us, there is no free will. I argue that their argument fails for two independent reasons. The first reason is that they fail to show that difference-makers are independent causes. The second reason is that physical realizers of mental states can be individuated in a way that makes both mental states and their realizers difference-makers.

KEYWORDS:

• Difference-making
• mental causation
• free will
• exclusion problem
• neurosceptical argument

Acknowledgements

The author is very grateful for helpful comments from two anonymous referees for this journal. The author would also like to thank Ragnar Francén for many discussions about the questions addressed in this paper, and Maria Svedberg for comments on an earlier version presented at the Stockholm June Workshop in Philosophy in 2020.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 We must not accept this claim. Perhaps difference-makers lack physical properties whatsoever – but then, it seems, difference-making causation collapses into full-blown dualism. As I understand List & Menzies, difference-making mental causation is not dualist causation, but essentially non-reductive mental causation in a physical world. If, on the other hand, difference-making is a dualist approach mental causation, then we can disregard the question of how mental and physical states are related and concentrate on the question of how abstract states can interact with physical states – in other words, we’re back at the old Cartesian discussion about the relation between mental and physical states or events.

2 This is at least how I interpret their view, as expressed as follows: ‘(…) [C]onsider the flask of boiling water. Its full molecular microstate at the time of the breaking may well be a sufficient cause for the breaking, and the boiling of the water supervenes on that microstate. Yet, it is the boiling that is the difference-making cause of the breaking, not the underlying microstate. If the boiling had occurred, but had been realized by a slightly different microstate, the flask would still have broken, and if the boiling had not occurred, the flask would have remained intact. So, the positive and negative conditionals for difference-making are satisfied when C is the boiling of the water and E is the breaking of the flask.’ (List and Menzies 2017, 280).

3 List & Menzies do not give a detailed explanation of why multiple realizability and difference-making mental causation provide room for free will. In List’s more recent book Why free will is real (2019), he is more explicit about this, and call his view of free will a form of ‘compatibilist libertarianism��: ‘ (…) [A]s I have shown, free will requires a form of indeterminism. It requires indeterminism at the agential level (…) I have (…) argued that the relevant form of indeterminism – namely, agential indeterminism – is supported by our best theories of agency (…) At the same time, I have argued, all this is compatible with physical determinism (…).’ (2019: 152). Difference-making mental causation plays a central part of the theoretical framework that List builds to defend this view of free will, since this causal account allows for irreducible mental states to cause actions, and exclude physical states as causes of actions.

4 Responsibility compatibilism is not a homogenous theory. The compatibilists I mention here have different ideas about what it takes to be a responsible agent. Compatibilists also disagree about how to understand the possibility of doing otherwise, and if it is a requirement at all for moral responsibility. These differences aside, compatibilists often share the common feature of describing the requirements for responsibility in terms of certain mental abilities/capacities/states, and that these are causally related to actions.

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Alva Stråge

Alva Stråge is a PhD in theoretical philosophy. She defended her dissertation Minds, Brains, and Desert: On the Relevance of Neuroscience for Retributive Punishment in 2019 at Gothenburg University, Sweden. Her philosophical interest spans over a wide range of questions, but for the moment she is mainly occupied with thoughts on multiple realizability, the nature of causation, and questions of how folk psychology governs moral judgments.