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Agent-causal libertarianism, statistical neural laws and wild coincidences

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Abstract

Agent-causal libertarians maintain we are irreducible agents who, by acting, settle matters that aren’t already settled. This implies that the neural matters underlying the exercise of our agency don’t conform to deterministic laws, but it does not appear to exclude the possibility that they conform to statistical laws. However, Pereboom (Noûs 29:21–45, 1995; Living without free will, Cambridge University Press, Cambridge, 2001; in: Nadelhoffer (ed) The future of punishment, Oxford University Press, New York, 2013) has argued that, if these neural matters conform to either statistical or deterministic physical laws, the complete conformity of an irreducible agent’s settling of matters with what should be expected given the applicable laws would involve coincidences too wild to be credible. Here, I show that Pereboom’s argument depends on the assumption that, at times, the antecedent probability certain behavior will occur applies in each of a number of occasions, and is incapable of changing as a result of what one does from one occasion to the next. There is, however, no evidence this assumption is true. The upshot is the wild coincidence objection is an empirical objection lacking empirical support. Thus, it isn’t a compelling argument against agent-causal libertarianism.

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Notes

  1. Likewise, by ‘neural factors’ I mean all factors relevant to a nervous system’s behavior excluding anything the person qua irreducible agent does.

  2. It should be noted that, while Pereboom is talking about a class of possible actions, he is more precisely talking about what would be the case if (or when) a .32 probability ‘a physical component’ of each of these actions will occur actually applies in each of ‘a large enough number of instances’ (2013, p. 112). This is made clear by his focus on what we should expect, ‘in the long run’ (2001, p. 85), if (or when) this is, in fact, the case; namely—that the actions in this class are chosen ‘close to 32% of the time’ across these instances. The reason for this focus is that—as Pereboom realizes and as will come into play in Sect. 4—there must be at least one action with a physical component that has a certain antecedent probability of occurring in each of a large enough set of instances for the ‘dovetail’ of expectations and an irreducible agent’s settling of matters to ‘amount to a wild coincidence’ (2001, p. 85). If not, agent-causal libertarians can offer a plausible explanation for why expectations are always met. To illustrate, if, for example, a .32 probability an agent will perform any one of a number of actions applies to only one instance, the agent can perform any of these actions or none of them, and her behavior will conform to expectations either way. Thus, in such cases, expectations are always met regardless of what the agent does. I thank an anonymous reviewer for helping me see the importance of clarifying this here.

  3. Vargas (2013) has recently suggested agent-causal libertarians are likely to take this position (p. 69).

  4. For illustrative purposes—to keep things simple—I will focus on a particular possible action (i.e., hand-raising) with a physical component that has a certain antecedent probability of occurring in each of a number of instances. This is a slight variation from Pereboom’s example—discussed in Sect. 3—involving a class of such actions. However, in this context, the main difference between considering a specific action and a class of actions is the number of physical components involved, and the overall complexity. This shift also enables us to consider a particular example, and action, which helps keep things more concrete. For my purposes here, this shift is, otherwise, inconsequential. Whether talking about a physical component of a particular action or a class of actions—as we will see below—the crux of the matter is that there must actually be at least one possible action with a physical component that has a certain antecedent probability of occurring in each of ‘a large enough number of instances’ (Pereboom 2013, p. 112), and this probability must be incapable of changing as a result of what one does from one instance to the next, for the wild coincidence objection to work. Otherwise, the agent-causal libertarian can give a plausible explanation for why an irreducible agent’s behavioral patterns always conform to expectations. In other words, this conformity needn’t be a wild coincidence. This, for example, includes when this conformity involves all ‘possible actions, each of which has a physical component whose antecedent probability of occurring is approximately 0.32’ (Pereboom 2013, p. 112; emphasis added) as much as a particular possible action with a physical component that has a .32 probability of occurring. I thank an anonymous reviewer for bringing it to my attention that it would be helpful to point this out.

  5. Here, I will be conservative by using a p value of .10 to determine whether it should be concluded that expectations aren’t met. In comparison with the traditional value of .05, this will increase the likelihood of drawing the conclusion that expectations aren’t met.

  6. Barnard’s test—another test for whether frequency patterns meet expectations—also indicates Ellie could raise her hand anywhere between zero (Wald Stat. \(=\) 1.52; Nuissance parameter \(=\) .01; p \(=\) .13) and three times (Wald Stat. \(=\) 1.3, Nuissance parameter \(=\) .01, p \(=\) .15) and expectations would be met.

  7. In this case, even though, at the outset, one has a certain probability of behaving in a certain way in each of a set of occasions, the probability one will behave in this way might end up differing from one occasion to the next depending on what one does on each occasion.

  8. For example, there is psychological evidence that desires and will-power can wax and wane depending on what one does, or doesn’t do, throughout the day (e.g., Hofmann et al. 2011).

  9. For example, Steward (2012), an agent-causal libertarian, seems to suggest as much when she indicates that—on her view—agents sometimes settle matters in advance (cf. pp. 39–42).

  10. Of course, this doesn’t rule out the possibility that something might intervene and thereby affect inclining factors in a way that increases the probability she will raise her hand on these occasions. This might include other things she may do (e.g., engage in certain thought processes).

  11. Though she might influence whether they wax or wane.

  12. On some occasions, that she doesn’t raise her hand might be settled by her across previous occasions, where, by acting, she makes it so inclining factors wane to the point she has no motivation, and will not act on a subsequent occasion, barring some change.

  13. Alternatively, imagine there is a .87 probability Ellie will raise her hand on each of five occasions (cf. Pereboom 2001, p. 85). She may, nevertheless, not raise it on the first occasion, which might make the probability she will raise it on the second occasion drop to .25. Again, she may not raise her hand on this occasion, making the probability she will raise it on the third occasion drop to .2. She may, then, not raise her hand on the third and fourth occasions, which might make the probability drop further to .17 and .15, respectively. Given this, the mean probability of her raising her hand on these occasions ends up being .328; and expectations are met even if she never raises her hand (\(\chi ^{2}{}_{1}=2.44\), \(p=.12\)).

  14. I thank an anonymous reviewer for alerting me to the value of providing this summary.

  15. For e.g., see: Wolters et al. (2003), Huber et al. (2004), Floyer-Lea et al. (2006), Roy et al. (2007), Albert et al. (2009), Feldman (2009; 2012), Wang (2010), Mrachacz-Kersting et al. (2012), Orban de Xivry et al. (2013), Koch et al. (2013), Hammerbeck et al. (2014), Barker et al. (2014), McNickle and Carson (2015), and Chao et al. (2015). Also, it has, for instance, been observed that, as a behavior is repeated, certain motor-related neural activities become more probable under certain conditions (e.g., Costa 2007; Wickens et al. 2007; Graybiel 2008; Verstynen and Sabes 2011; Hikosaka et al. 2013; Kim et al. 2015; Anderson et al. 2016).

  16. While nothing I’ve said here depends on it, it is tempting to speculate that these spontaneous fluctuations might increase the likelihood of variability in an agent’s choices and, thus, in her experiences. Engaging in a variety of different behaviors, and having a variety of experiences, in the same or similar circumstances would increase an agent’s exposure to novelty. This may have advantageous consequences on flexibility, increased awareness of possibilities, and learning. I thank an anonymous reviewer for prompting me to make this point.

  17. And, again, the wild coincidence objection involves assuming this might be the case.

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Acknowledgements

I thank Tim Steenbergh for fruitful conversations about probabilities, and John Hyman for suggestions on how to simplify the prose. I would also like to thank three anonymous reviewers for the time they gave the manuscript. Their criticisms and suggestions helped make this paper stronger. This study was funded by a Lilly Endowment and the Lumen Research Institute.

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Runyan, J.D. Agent-causal libertarianism, statistical neural laws and wild coincidences. Synthese 195, 4563–4580 (2018). https://doi.org/10.1007/s11229-017-1419-7

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