In this the third part of a look at what science has to say on the concept of free will, we will delve into the relationship between volition and consciousness. And it gets weird. I won’t even rag on William ‘Lame’ Craig this time, though it is always tempting. One thing I should say before continuing is what version of free will I am rejecting: the traditional contra-causal free will which is a consequence of discredited dualistic notions. Tom Clark puts it this way:
If you imagine a situation in which you are behaving and you make a particular choice, many people suppose that given that situation exactly as it transpired you could have chosen something other than what you did. But a science-based naturalism looking at the situation as it arises will see the choice as a function of the exact conditions that were present at the time. So if you play that scenario there is no reason to think that anything else would have happened. Many people think, in supposing that they have contra-causal free will, that had they been in that situation even with the same desires, the same exact circumstances inside and outside themselves, they could have chosen or done something other than what they did. And this is what [naturalists] are denying. This is what I think a thorough science-based naturalism challenges is this idea of a causally-autonomous, metaphysically-autonomous self that somehow gets to cause things but is itself not fully caused1.
There are some types of free will that are compatible with determinism and we will get to those later. True contra-causal free will just has too many issues associated with it to be a viable concept. One I have alluded to before, that we would be paralyzed into inaction if a large part of our everyday actions weren’t calculated at a subconscious level. There are just too many choices at every moment. ‘Walking across the street’ is a high-level intention, but each individual step requires a decision to place the foot calculated from terrain, balance, etc. If you have to think about it, you will simply fall over. Second is that contra-causal free will means that people would be far less predictable than they are, which is not a good thing.
Continuing from part deux, the experience of making a voluntary action is subjective and very different from an equivalent reflex action. If we answer Wittgenstein’s question “What is left over if I subtract the fact that my arm goes up from the fact that I raise my arm?”2 we have a way to measure the effect of volition on brain function. In investigating the answer to Wittgenstein’s question, a recent study has some telling results3. Seven patients undergoing brain surgery had their parietal and premotor cortex electrostimulated. When the parietal lobe was stimulated, the subjects experienced a strong drive to move a contralateral extremity. When the premotor cortex was stimulated, motion of a contralateral extremity or mouth resulted. But along with movement with premotor cortex stimulation came a total denial from the subject that the limb had moved! What this shows is that sensation of movement is subjective and comes not from the movement itself (via feedback from muscles, for instance), but from the generation of intent and predicted consequences within the brain itself.
It is the conscious intention to make an action that seems to cause the action itself, giving rise to the illusion that we have free will. But no dualist explanation for volition can possibly withstand scrutiny, especially since mind-brain dualism has long been discredited by ugly facts. Both conscious intention and action seem to both be a result of brain activity. Other explanations for this sensation have been put forward. It has been proposed that the mind (a product of the brain, remember) assumes a causal path from conscious intention to the action in order to rationalize the correlation between the two, particularly since both driven by neuronal preparation4. Another possible explanation for our sense of free will is that conscious intention is not a real mental state at all, but a rationalization retrospectively inserted into the consciousness stream that we intended to take the action5. In other words, we are duped into thinking that we intended to cause an action when we are being informed of the action after-the-fact. Psychoses can produce experiences of intention which are associated with unusual causal explanations of connections between events. For instance, one sign of schizophrenia is the attribution of themselves as causing events which are beyond their control7.
Remember Libet’s experiment8 outlined in Part One? While the ‘urge to move’ occurred roughly 200 ms prior to hand movement, readiness potentials were observed about 1 sec before the motion. The brain is preparing to move long before the experience of intent. In addition to this, events occurring post-action can contribute to the experience of intent. But the results from experiments such as the one in reference 3 and similar work seem to disprove the retrospective hypothesis, since stimulation of certain brain regions can produce an urge to move in the absence of actual movement. But I’m unconvinced that the evidence rules out a retrospective explanation for our experience of intent as there may be more than one way to produce it.
Other experiments have shown that the later phase of the readiness potential in the brain region contralateral to the body part being moved (remembering that the brain is cross-wired) is required, rather than a general preparedness to move. Such experiments involved giving subjects a choice of which hand to move in a modified Libet experiment. I mentioned one such experiment in Part One where it could be predicted from fMRI measurements which hand would be moved up to 8 seconds beforehand9 and could represent detectable patterns in an earlier stage of the causal chain generating actions and our perception of intent and agency (see figure).
One of the big fears of those subscribing to contra-causal free will is the belief that it is essential to a moral grounding. If our actions are determined, these people think, then we can not assign blame to anything that we do. But this is because such people have an overly strict view of determinism. As Tom Clark writes10:
Fortunately, there is a long-standing philosophical view of human freedom, known as compatibilism….. Although not yet widely disseminated in lay culture, this view holds that we are free to the extent our actions flow from our character-based motives and desires, not from coercion or duress. Such freedom is compatible with our being fully caused creatures, in that it is a freedom from external or internal constraints (e.g., from chains and psychoses), not the patently implausible ultimate freedom to choose our selves or actions ex nihilo. Suppose we had such freedom: on what basis would we choose?
On a compatibilist view, what justifies moral judgments is that those acting freely as described above are potentially sensitive to such judgments: as rational agents they can be cognizant of, and have the capacity to conform to, our moral codes as expressed in law and social expectations. This view of morality—the instrumental shaping of behavior—needs no freely willing, intrinsically deserving agent that could have done otherwise in the exact situation in which a given behavior arose. Moral agents, instead, are simply that rather broad class of persons who can anticipate the rewards and sanctions carried by moral evaluation (e.g., praise, credit, blame, punishment); it makes pragmatic sense to hold moral agents responsible to such standards, since doing so helps modify their behavior. On the other hand, those with serious mental illness or those forced at gunpoint (or similarly threatened) to act contrary to their characters are not held responsible.
No ultimate authority is necessary to behave morally. For those who think fear that immorality is a result of the non-existence of a supernatural being endowing us with free will, Clark has this to say-
Naturalism also undermines the “abuse excuse”: true, persons are caused in every respect, but there are still adequate justifications (deterrence, incapacitation, and personal reform) for incarcerating wrongdoers, if not for capital punishment and “hard time” in prison…. Since moral mechanisms have a clear social function that science can help us to understand and improve, no longer will morality have to seek shelter from science. We may not be free in the exceptional, ultimate sense we once supposed, but we are more than compensated by the pragmatic benefits that flow from recognizing our complete inclusion in the causal order.
It’s clear from these discussions that our understanding of volition is in its early stages, but I think it is just as clear that contra-causal free will is a myth. We act on our wants and desires so that we feel that we are exercising free will, but our wants and desires are determined so that our actions are predictable. Imagine the chaos in the world if you could not make such predictions of others’ behavior.
So much for contra-causal free will.
- Clark T. Scientific naturalism and the illusion of free will. Point of Inquiry podcast (http://cdn4.libsyn.com/pointofinquiry/POI_2009_06_12_Tom_Clark.mp3?nvb=20090730193409&nva=20090731194409&t=0dcb77e614c754f0aee13). Retrieved July 30, 2009.
- Wittgenstein L. In Philosophical Investigations. Blackwell. (1953)
- Desmurget M, Reilly KT, Richard N, Szathmari A, Mottolese C, Sirigu A. “Movement intention after parietal cortex stimulation in humans.” Science 324:811-13 (2009)
- Wegner DM. The Illusion of Concscious Will. MIT Press. (2003)
- Dennett D, Kinsbourne M. Time and the observer. Behav Brain Sci 15:183-247 (1992)
- Haggard P. Human Volition: towards a neuroscience of will. Nat Neurosci Rev 9:934-46 (2008)
- Haggard P, Martin F, Taylor-Clarke M, Jeannerod M, Franck N. Awareness of action in schizophrenia. Neuroreport 14:1081-5 (2003)
- Libet B, Gleason CA, Wright EW, Pearl DK. Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act. Brain 106:623-42 (1983)
- Soon CS, Brass M, Heinze HJ, Haynes JD. Unconscious determinants of free decisions in the human brain. Nature Neurosci 11:543-45 (2008)
- Clark T. Applied ethics: Science and Freedom. Free Inquiry magazine 22 (2002)