“Local determination”, even if we could find it, does not challenge free will: Commentary on Marcelo Fischborn

Abstract

Marcelo Fischborn discusses the significance of neuroscience for debates about free will. Although he concedes that, to date, Libet-style experiments have failed to threaten “libertarian free will” (free will that requires indeterminism), he argues that, in principle, neuroscience and psychology could do so by supporting local determinism. We argue that, in principle, Libet-style experiments cannot succeed in disproving or even establishing serious doubt about libertarian free will. First, we contend that “local determination”, as Fischborn outlines it, is not a coherent concept. Moreover, determinism is unlikely to be established by neuroscience in any form that should trouble compatibilists or libertarians—that is, anyone who thinks we might have free will. We conclude that, in principle, neuroscience will not be able undermine libertarian free will and explain why these conclusions support a coherent compatibilist notion of causal sourcehood.

Keywords:

• Compatibilism
• decision
• determinism
• free will
• libertarian freedom
• neuroscience

Notes

1. Fischborn uses the term “local determination” in his paper, and because we are discussing his arguments we follow his usage. However, as best as we can tell, he is talking about a scope-limited law-governed determinism, so we think that calling it “local determinism” would be more felicitous.

2. Deery and Nahmias (unpublished) argue that the manipulator could not pull off the trick even in a deterministic universe, since at the time she does her calculations she would not have access to events that are outside her past light cone—too far away to reach her even at the speed of light—but those unknowable events might be causally relevant to the agent’s actions in 30 years, since they are in the past light cone of those actions.

3. Perhaps one could be developed if one was aiming for the conclusion Pereboom (2001) aims for: that free will is incompatible with one’s actions being causally determined by factors beyond one’s control. But Pereboom never defines exactly what he means by such causal determination, and it’s not clear how the cases required for the Manipulation Argument work if universal determinism does not apply (see note 6 below).

4. Recognizing this point is crucial, we believe, in avoiding the misleading intuition that if our brains cause our decisions, we don’t. Of course, we need to deal with the causal exclusion argument here (Kim, 2000), but that argument does not require deterministic causal relations at the lower level (though see Tse, 2013 for an argument that it does). See List and Menzies (in press) for a response to Kim’s argument.

5. Nahmias, Shepard, and Reuter (2014) present experimental results suggesting that most people do not find free will to be undermined by the stipulation of perfect prediction of decisions based on preceding neural activity—which might suggest local determination in the brain.

6. It may be that Fischborn is gesturing here towards an argument that is similar to van Inwagen’s Mind Argument (1983), something like: (1) No one has a choice about the neural activity that causes later decisions; (2) if no one has a choice about what causes X, then no one has a choice about X; (3) so, no one has a choice about their decisions. We think both of these premises are implausible.

7. By analogy, interactions among molecules might be deterministic (putting aside quantum effects for now), but any law-like causal relations among colliding billiard balls will be multiply realizable by different molecules and will be described in terms of the higher-level structures and interactions among the balls, not in terms of the laws that describe the molecules.

8. Note that Kane (1996) relies on non-linear dynamics to allow quantum indeterminism to “percolate up” to influence which among competing neural networks “wins out” to cause the outcome of a close-call decision (or SFA). But the chaos without the quantum indeterminism still gets us a lack of deterministic relations between specifiable types of neural activity and complex decisions or behaviours.

9. A reviewer helpfully alerted us to a manuscript by List and Pivato (2015) that provides a viable definition of local determinism, such that states within a spatio-temporal region L nomologically necessitate the states in a larger spatio-temporal region L*. We are not arguing against the theoretical coherence or possibility of local determinism of this sort. However, such a definition requires that L be a “closed” system that does not receive input from outside of that spatiotemporal region. The brain (and behaviourally relevant spatiotemporal subsets of it) is not a closed system, so the possibility of local determinism of this sort is not relevant to the question of free will.

10. There are a number of responses to incompatibilist worries about causal sourcehood. For example, Roskies (2012) explains how self-shaping can occur even in a deterministic world and uses interventionist theories of causation to show why it is legitimate to refer to an agent as the causal source of his or her own character. Deery and Nahmias (2016) also use causal interventionism to provide a compatibilist account of causal sourcehood. They apply this account to the Manipulation Argument to elucidate a principled difference, relevant to free will and moral responsibility, between a manipulated agent and a (merely) determined agent. The manipulated agent is not the causal source of his actions because there is another source (the manipulator) that better predicts and explains his decision. The same is not true for the determined agent.