Abstract
Benjamin Libet’s work paved the way for the neuroscientific study of free will. Other scientists have praised this research as groundbreaking. In philosophy, the reception has been more negative, often even dismissive. First, I will propose a diagnosis of this striking discrepancy. I will suggest that the experiments seem irrelevant, from the perspective of philosophy, due to the way in which they operationalize free will. In particular, I will argue that this operational definition does not capture free will properly and that it is based on a false dichotomy between internal and external causes. However, I will also suggest that this problem could be overcome, as there are no obvious obstacles to an operationalization of free will that is in accord with the philosophical conception of free will.
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Notes
See Libet (2002), where he provides a long list of fellow scientists who have “not only accepted our findings and interpretations, but have even enthusiastically praised these achievements and their experimental ingenuity” (p. 292).
One can get a good sense of the striking differences in the assessment of Libet’s findings (and related empirical evidence) from a discussion of the topic “Is free will an illusion?” in the Chronicle of Higher Education (2012, March 18), which includes contributions from scientists and philosophers.
Although I have come across this view many times in conversation with other philosophers, it is difficult to find clear statements in print. The main reason for this is probably that the philosophers who publish academic work on this topic are the ones who take the empirical challenge to free will seriously, whereas the ones who think it is irrelevant do not bother to write about it. However, statements of the view that the evidence is simply irrelevant to free will (or “no threat at all”) are provided by three philosophers on the BBC Radio 4 program “In our time: philosophy” (2011, March 10).
Arguably, what-decisions are more significant, because when-decisions are usually subordinate to what-decisions in the sense that we usually decide when to do something in order to decide how to implement a what-decision.
Two recent studies have raised serious questions concerning the measurement and interpretation of the RP. The experiments in Miller et al. (2011) suggest that effects of the clock-monitoring could be partly responsible for the main finding in the Libet experiment. The experiments conducted by Schurger et al. (2012) suggest that the precise timing of the decision is partly determined by ongoing spontaneous fluctuations of neural activity and that the decision to act might occur much later in the RP process than Libet assumed. Further, experiments conducted by Schlegel et al. (forthcoming) raise serious doubts about Haggard and Eimer’s findings concerning the role of the LRP. Given this, it seems no longer credible to hold that the main findings of the Libet experiment are an established empirical fact (as it has often been claimed). However, further experiments are required to establish the truth on those issues, and the mentioned studies do not challenge the results of Soon et al. (2008).
According to Libet, a conscious intention to initiate a movement “should precede or at least coincide with the onset of the specific cerebral processes that mediate the act” (1985, p. 529). One has to assume here that by “mediate the act” Libet meant “initiate the act”. Otherwise, the conclusion that the initiation of a spontaneous voluntary act begins unconsciously does not follow. Further, one must assume that the RP is such a “specific cerebral processes” that initiates the act. This assumption, I should mention, has attracted a lot of criticism. See Keller and Heckhausen (1990), Zhu (2003), Mele (2009), for instance.
Another prominent empirical challenge concerning the role of consciousness in the initiation of action is due to Wegner (2002), who argued that the experience of conscious will is an illusion. On some occasions, Wegner appears to use the terms ‘conscious will’ and ‘free will’ interchangeably, but he does not draw any explicit conclusions about free will. I have addressed Wegner’s challenge elsewhere (Schlosser 2012a).
See, however, Schlegel at al. (forthcoming).
However, the findings are controversial due to the fact that the unconscious brain activations predict the conscious choices only with a relatively low accuracy of about 60 %. In other words, the decoded unconscious brain activations raise the probability of the subsequent conscious choices to just above the level of chance.
See note 4.
Note that this provides a necessary condition: the choice of an action is made with free will proper only if it is based on reasons. It is not meant to provide a sufficient condition; it is not meant to give a full definition; and it is not meant to give an explanation of what freedom is.
See also Fischer and Ravizza’s (1998) influential account of reason-responsiveness. They argue that “reason-receptivity” is relative to subjective features of the agent, but that it cannot be reduced to “the agent’s point of view”. Rather, reason-receptivity must be “grounded in reality” (p. 73). Further, they claim that this view fits with “the widest possible selection of plausible views about reasons for action” (p. 68, note 11). Note that this view is compatible even with source libertarianism, according to which the agent must be the source or origin of his or her free choices (Kane 1996, for instance). All source libertarians acknowledge that the agent should be influenced by reasons. Given that genuine reason-responsiveness requires at least some sensitivity to external factors, even source libertarians can and should allow the influence of external factors.
One might think that such an action was free only if the reason did not determine the action and only if the agent could have done otherwise. According to compatibilists, free choices may be causally determined. What matters, rather, is that the choice of the action is not coerced or manipulated. This condition is satisfied: the fact that one is persuaded by a factor is incompatible with being coerced or manipulated by that factor. In contrast, incompatibilists would insist that the reason must not determine the choice. This is also compatible with what I have claimed: we may assume that a factor that provides a reason exerts only a causal influence on the choice of the action. Is it required that the agent could have done otherwise? This issue has been very controversial (see, for instance, Dennett 1984; Van Inwagen 1989; Kane 1996). Fischer and Ravizza (1998) have argued that reason-responsiveness does not require the ability to do otherwise. Elsewhere, I have proposed that the ability to do otherwise can be analyzed in terms of reason-responsiveness (Schlosser 2012b). Be that as it may. The important point is that nothing hangs on this issue here, for everything that I have claimed here is compatible with both the affirmation and the denial of the view that the agent must be able do to otherwise.
I assume here that the conscious events that proximately precede the movements are conscious intentions. I should note, however, that this assumption has also been questioned. For instance, Keller and Heckhausen (1990, p. 359) suggested that the conscious events in question were the “result of selective attention” to look for an urge to move, which was, in turn, induced by the artificial setup and the instructions of the experiment. They suggested, in other words, that the conscious events in question are neither intentions nor conscious events that precede ordinary actions.
I assume here that causation may be non-deterministic, such that causes raise the probability of effects.
See note 10.
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Schlosser, M.E. The neuroscientific study of free will: A diagnosis of the controversy. Synthese 191, 245–262 (2014). https://doi.org/10.1007/s11229-013-0312-2
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DOI: https://doi.org/10.1007/s11229-013-0312-2