In this rather ambitious book, Gregg D. Caruso attempts to make the case for free will skepticism, arguing that our feeling of freedom is an illusion. In making his case, Caruso explores some territory often left unexplored by many philosophers working on free will. For instance, he devotes a large chunk of his book to explicitly exploring the connection between consciousness and free will. Moreover, a substantial portion of the book is devoted to examining the implications of recent work in neuroscience, cognitive psychology, and social psychology for free will.
Caruso labels the version of hard-incompatibilism to which he is committed "hard-enough determinism" (p. 4). He asserts that the neural processes that underlie our decision-making are part of a causally determined or at least "near determined" system (p. 4). Thus, he leaves open, as he should, the possibility that there is at least some indeterminism in the universe. But he maintains that any quantum indeterminacies "are of such a vanishing magnitude as to cancel out before reaching the required neural level" (p. 4).
Caruso explicitly endorses and offers a limited defense of a higher-order thought (HOT) theory of consciousness (pp. 145-164). Unfortunately, there is no sustained engagement with viable alternatives to the HOT theory. It is not obvious that an adequate case for the illusion of conscious free will requires accepting the HOT theory. In fact, reliance upon the HOT theory strikes me as a liability given the criticisms of the theory in the literature (e.g., Byrne 1997 and Dretske 1995).
Regarding the book's organization, Caruso spends the first three chapters focusing primarily on the standard philosophical debates over free will, critiquing both compatibilist and libertarian theories of free will. By the fourth chapter, compatibilism is off the table as a live option. The remaining four chapters are devoted to the relationship between consciousness and free will, with a heavy emphasis on surveying the empirical evidence that Caruso argues counts against normal human agents having (libertarian) free will.
Caruso's critique of existing theories begins with libertarianism. He focuses his attention on agent-causal and event-causal strategies. On agent-causal approaches, agents possess causal powers that enable them (qua substances) to directly cause their decisions or the acquisition of an intention. Event-causal strategies take free decision-making to involve indeterministic processes involving the agent's mental states and events doing the causal work.
Caruso casts his net widely in critiquing agent-causal libertarianism, not focusing on any single defense of agent-causalism. His critique of event-causalism is more focused, targeting the work of Robert Kane (1996). In critiquing Kane, Caruso mostly echoes the standard objections in the literature. For instance, he questions the empirical plausibility of Kane's theory and argues that decisions that are the result of indeterministic processes are unintelligible (pp. 42-55).
In making a case against agent-causalism, Caruso appears at times to be sparring with a straw opponent. Caruso characterizes agent-causalism as a theory committed to a dualist picture of the self. And it is this alleged feature of agent-causal strategies that is his main target; he argues that agent-causation involves a violation of physical causal closure (pp. 29-42).
Unfortunately, Caruso runs roughshod over important distinctions between the views of different proponents of agent-causalism, ignoring important differences that may render some defenders of agent-causalism immune to Caruso's main objection. The end result is that his critique of agent-causalism is substantially weaker than it could have been.
In making his case against compatibilism. Caruso begins by presenting the consequence argument for incompatibilism -- which concludes that our decisions are not "up to us" in the sense required for free will if they are the causal consequences of past events and laws of nature that are not up to us (van Inwagen 1983, pp. 16 and 55-105). He then turns to making a case against compatibilism from recent work in experimental philosophy on folk intuitions about free will and from the phenomenology of agency. He argues that the findings from experimental philosophy and the phenomenology of agency count against regarding compatibilism as the ordinary common-sense theory of free will (pp. 89-90). I will not discuss his response to compatibilist replies to the consequence argument, but instead focus only on the significance of experimental findings and phenomenology for the tenability of compatibilism.
Regarding folk intuitions about free will, while the sentiment I express may be revisionist in spirit, it is not clear that a defender of compatibilism -- or any theory of free will, for that matter -- must be defending the common-sense view of free will. Of course, the data from experiments on folk intuitions about agency are interesting and helpful -- especially if we wish to make claims about what the common-sense understanding of free agency actually is. But what we are after in our metaphysical theorizing is an account of what free will is and if we have it. We can work on this problem without mentioning what the allegedly common-sense view is.
Even if we agree that our metaphysical theorizing about free will should track the folk concept of free will, the results of studies to date have been mixed. Caruso ignores the results of studies that suggest that, "people's interpreting determinism to entail bypassing may be the best explanation for ordinary people's intuitions that appear to support the incompatibility of determinism and [free will and moral responsibility]" (Nahmias and Murray 2011, 207). Of course, Caruso may be right, the folk view of free will may very well be incompatibilistic. But the selective citation of studies he offers his readers does little to show conclusively that incompatibilism is the folk view.
Regarding the phenomenology of agency and compatibilism, Caruso claims that compatibilists have ignored the phenomenology of agency. He asserts that, "We actually feel as though we have the power to choose in a way that is not causally determined by antecedent events and conditions" (p. 89). Whether or not compatibilists have ignored the phenomenology of agency or, better, treated it as a "metaphysical illusion" (Smart 2006, pp. 172-173), Caruso's own case from the phenomenology of agency is rather weak. He offers little data beyond the first-personal reports of incompatibilists found in the literature on free will. Perhaps more importantly, he ignores experimental data that, while not conclusive, supports compatibilism more than libertarianism (see Nahmias, Morris, Nadelhoffer, and Turner 2004).
Turning to his case for the illusion of conscious free will, Caruso argues, regarding the function of consciousness in agency, that consciousness "is needed for the executive control and guidance required for free will" (p. 101). But he contends that our sense of ourselves as in control of our decisions in the sense required for (libertarian) free will is an illusion because of the automaticity of many mental processes (p. 141). Later, in his discussion of self-consciousness and agency, he adds that our sense of unity of consciousness in acting and of our authorship and ownership of our actions does not require accepting "a libertarian or Cartesian" view of ourselves (p. 255).
For reasons I cannot explore in any detail here, Caruso's claims about the importance of consciousness for the exercise of free will and the extent to which we must be conscious of the factors that play a role in the etiology of our decisions strike me as somewhat exaggerated. This is not to say that our being able to be aware of our deliberation and decision-making is unimportant. But it is not apparent why we as complex systems must be aware of everything occurring within ourselves that is causally relevant to our making decisions in order to have a veridical conscious experience of making a decision for reasons.
Finally, as one would expect in a work such as this, Caruso discusses recent widely debated work in neuroscience and social psychology that allegedly shows that our agency in conscious decision-making is illusory. He focuses his attention primarily on the work of Benjamin Libet and Daniel Wegner. Libet (1985) famously claimed to show that our decisions to perform overt actions occur approximately half a second before we become aware of them. Wegner (2002) has recently argued on the basis of both his own experiments and those of others that our conscious experiences of mental causation are illusory.
While Caruso uses the work of both Libet and Wegner to support his case for free will illusionism, he parts company with Wegner on one point, arguing that, "there can be real mental causation occurring at the level of unconscious mental states" (p. 210). But Caruso expresses agreement with Wegner that "our feeling of conscious will is an illusion" (p. 211).
Caruso ignores some of the most prominent responses by philosophers to Wegner's work (e.g., Holton 2004, Mele 2009, and Nahmias 2002). While he does engage with the work of Alfred Mele (2009) on Libet, his reply to Mele only spans about two and a half pages (pp. 194-196).
In his treatment of Mele's replies to Libet, Caruso first discusses Mele's claim that the unconscious brain activity that precedes an agent's awareness of her decision can be the causal antecedents of her decision (Mele 2009, p. 51). Caruso argues that, at best, Mele shows that Libet's findings are "consistent with the possibility of causally effective intentions" (p. 195). Caruso then goes on the offensive, claiming that Mele's conceding that pre-conscious brain activity can play a role in the etiology of actions, including decisions, is somehow a fatal move. He writes that Mele's acknowledgement "that our actions have causal roots in pre-conscious brain activity ends up simply highlighting the problem, not solving it" (p. 195). The problem is that, as Manuel Vargas put it in his review of Mele 2009, "the causal buck doesn't stop with the agent" (Vargas 2009).
Regarding Caruso's first point in response to Mele, if Libet's findings are consistent with Mele's interpretation, then the assertion that conscious will is an illusion is unwarranted. It may be an illusion. But we cannot justifiably assert that it is in fact an illusion.
As for the charge that Mele has effectively acknowledged that our agency is somehow diminished in a way that one must infer would threaten our having free will, there are substantial action-theoretic assumptions at work here that are not being acknowledged by Caruso. It seems that he is assuming that unless all of the causal antecedents of an agent's decision (whether deterministic or indeterministic) are available to consciousness and, apparently, manipulation by the agent, then the agent's agency is vitiated.
The correctness of such a conclusion as the immediately foregoing is not obvious. As I noted above, human agents are complex systems whose intentional behavior is the result of complex causal processes. It is unreasonable to expect that everything that is involved in the production of an agent's decision is available to consciousness. What we should expect is a mixture of conscious and unconscious processes causally contributing to our decision-making (Baumeister, Masicampo, and Vohs 2011).
What Caruso seems to miss, but Mele points out, is that, "In the philosophical literature, free will's primary locus of operation is typically placed . . . in the act of deciding (or choosing)" (2009, p. 69). But Caruso seems to think that even if we are aware of our making decisions, so long as some of the causal antecedents of our decisions are not available to consciousness at the time they occur, then free will is an illusion. Such a line of reasoning is in need of substantial defense.
In conclusion, there is a lot going on in this book that should be of interest to philosophers, neuroscientists, and psychologists interested in the free will debate. While frustrating at moments, Caruso deserves praise for making a comprehensive case for free will illusionism that engages with both the recent philosophical and empirical literature on human agency.
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 For instance, Timothy O'Connor's agent-causal theory of free agency seems immune to Caruso's argument. In part, this is because, while O'Connor is a property dualist, he rejects substance dualism and it is the agent qua substance that causes her intention to act in virtue of possessing an emergent agent-causal power. See O'Connor 2009.
Mele replies to Vargas 2009 in Mele 2012.
 Thanks to Shawn Jordan for his helpful comments on an earlier draft of this review.