The physiology of free will

The concept of human agency, wherein individuals possess the capacity to select their behaviour and navigate freely within their physical and social surroundings, while accounting for physical constraints and the presence of other sentient beings, has been ingrained in human culture since ancient times. This notion is widely embraced and deeply entrenched in our collective thinking. However, advancements in philosophy and scientific inquiry have gradually questioned the veracity of this belief, challenging the notion that freedom is an inherent and essential attribute of human beings, serving as a foundational principle for their interactions within society. Undoubtedly, we find ourselves situated in a distinct epoch of human history characterized by intensified scrutiny and challenges directed towards the concept of free will. Within scholarly circles, a range of viewpoints has emerged, such as eliminativism and illusionism concerning freedom, which employs theoretical arguments rooted in physical determinism to illustrate its inherent incompatibility with the notion of free will (Caruso, 2015; Smilansky, 2000). Additionally, interpretations derived from empirical findings in psychology and cognitive neuroscience have shed light on the apparent causal ineffectiveness of our conscious mental processes, as evidenced by seminal studies such as those conducted by Libet et al. (1983). It is worth noting that even proponents of the repudiation of human freedom and, by extension, society as a whole, encounter difficulties when endeavouring to implement the implications of such theories practically (Harris, 2012). Free will as a property of individuals and a social concept can be characterized by three conditions (Lavazza, 2016; Walter, 2009). The first is the ‘ability to do otherwise’. This is an intuitive concept: to be free, one needs to have at least two alternatives or courses of action from which to choose. If one has an involuntary spasm of the mouth, for example, one is not in the position to choose whether to twist one’s mouth or not. The second condition is the ‘control over one’s choices’. The person who acts must be the same as the person who decides what to do. To be granted free will, one must be the author of one’s choices, without the interference of people and of mechanisms outside of one’s reach. This is what we call agency, that is, being and feeling like the ‘owner’ of one’s decisions and actions. The third condition is the ‘responsiveness to reasons’: a decision cannot be free if it is the effect of a random choice, but it must be rationally motivated. If I roll a die to decide whom to marry, my choice cannot be said to be free, even though I will freely choose to say ‘I do’. On the contrary, if I choose to marry a specific person for their ideas and my deep love for them, then my decision will be free. These conditions that characterize free will, while rigorously defined from a theoretical point of view, are permeated with normative insights and rules that have been consolidated on our social practices from common-sense psychology. This framework is now challenged by a variety of philosophical arguments and empirical data. It is not, therefore, a matter of defending free will because it seems we cannot do without it (cf. Strawson, 1962), but of giving it a more circumscribed, precise and physiologically grounded characterization on a broad spectrum. In this contribution, we will not address the issue of determinism but focus on the possibility that the individual shows a real property called free will, which is amenable to verification and measurement. The key point in advancing the debate is to create an explanatory bridge between a concept that is, to varying degrees, theoretical, normative, functional and social, and a scientific approach that brings it back as far as possible to the physiology of the human being. The concept of free will is theoretical in that it is not completely operationalizable, especially the part related to the reasons for deciding to take an action. What counts as a reason is not easily discriminable quantitatively, and this also brings us back to the normative value of the concept of free will, which is used, for example, in deciding what penalty to impose on a defendant. The concept of free will is then functional because it concerns its use in a specific context, which is eminently a social context, although free will is strictly individual. It is important to stress that there are different definitions of free will and that this may result in different research perspectives from an empirical standpoint. For example, it is possible to distinguish between free will as a general property and agency and personal responsibility. This has implications for both the approach to endorse and the results that can be obtained (cf. Sjöberg et al., 2019).