Has Neuroscience Shown that Free Will is an Illusion?

Responding to Daniel Wegner

Cody Brooks

PH427 Genes Brains and Society

London School of Economics and Political Science

Submitted on January 12th, 2015

1

In recent decades, the debate concerning the nature of free will has seen renewed interest and

become a major point of contention among academics. While this debate has historically been

held primarily amongst the philosophical community, the contemporary resurgence is marked

by increased contribution from scientists. Indeed, since neurologist Benjamin Libet published

the findings from his pioneering study of human volition in 1985, his work has been central to

the discussion. Widely cited, Libet’s experiment has been taken by some as scientific

evidence that free will is an illusion.

In this essay, I will introduce a case against free will as formulated by Daniel Wegner, and

respond by advancing several challenges against his claim that free will is an illusion. In

doing so, I will call Wegner’s argument into question and suggest that it is not supported by

Libet’s experiment.

Libet’s ExperimentLet us begin by introducing Libet’s experiment. Employing methods devised by German

psychologist, Wilhelm Wundt, Libet began his experiment intent on measuring the time

between conscious decisions and voluntary action. For his experiment, Libet had subjects

watch a clock as its arms rapidly propelled around the dial. Participants were instructed to

spontaneously move their right hand at a time of their own choosing, while making note of

the position of the clock when they first became aware of the urge to move. At the same time,

electrodes, which had been placed on the scalp, recorded activity in the prefrontal motor

areas.1After hundreds of trials, Libet revealed the results of his experiment: “voluntary acts”

he wrote, “are preceded by electrophysiological ‘readiness potentials’ (RPs)” 550

milliseconds before movement, 350 milliseconds before conscious awareness of the desire to

move (W).2 Since publishing his results, Libet’s experiments have been recreated numerous

1 Haggard, 2008: 9352 Libet, 1985: 529

2

times.3 Though fluctuations in the time between RP and W have been reported, the data has

continued to show that W follows RP.

Wegner’s Case Against Free WillAlthough Libet believed that the 150 milliseconds between W and movement left enough

time for one to consciously repress the urge to act (a belief that I will return to), some have

interpreted his study as a rejection of free will. Referring to Libet’s experiment, in his book,

The Illusion of Conscious Will, Daniel Wegner writes:

It seems that conscious wanting is not the beginning of the process of making

voluntary movement but rather is one of the events in a cascade that eventually yields

such movement. The position of conscious will in the time line suggests perhaps that

the experience of will […] might just be a loose end—one of those things, like the

action, that is caused by prior brain and mental events.4

If the experience of free will is a by-product of unconscious brain processes, and we do not in

fact consciously will our actions, then free will, Wegner concludes, is an illusion.5

Wegner is not alone in his line of reasoning. Several articles and books have been published

detailing similar perspectives.6 Unfortunately, given present constraints I am unable to

provide a review of this literature. Moreover, although I believe that Wegner’s remarks are

representative of this mode of reasoning, support for this claim remains outside the confines

of this paper. As such, I will be focusing on the argument as Wegner formulates it, which I

take to be the following:

P1: Free will requires that one’s actions are consciously motivated.

P2: Science is showing that our actions are not consciously motivated.

3 For recreations of Libet’s experiment see: Haggard and Eimer, 1999; Keller and Heckhausen, 1990; Lau et al., 2004; Soon et al., 2008; and Trevena& Miller, 2002.4 Soon, 2002: 555 Ibid. 3426 For what is perhaps the most popular recantation of free will, see Harris, 2012.

3

C: Therefore, science is showing that we do not have free will.

In what follows, I will examine P2 and present several challenges for Wegner’s argument.

Libet’s ‘Free Won’t’Firstly, P2 requires that consciousness as represented by Libet’s‘ W’ is epiphenomenal or, in

Wegner’s language, ‘a loose end’ that holds no causal effect. Libet’s own interpretation of the

data challenges this position. Since “conscious intention is reported to appear about 150 to

200 ms before muscle activation,” Libet reasons that there remains the possibility that one

could consciously veto “the later phase of cerebral motor processing.”7 For Libet, this claim

was more than speculation: he believed his experiment had revealed evidence of the veto in

action. Some subjects had reported consciously aborting the urge to act. Furthermore, after

participants were instructed to veto developing urges, the resulting data showed a climbing

RP despite there being no subsequent motor activity.8 This might suggest that the participants

had in fact consciously repressed the urge to act. In the years since Libet published his essay,

there has been considerable debate regarding the existence of ‘free won’t.’9 At present, it is

not my mission to enter into this discussion; suffice it to say that the existence of ‘free won’t’

remains contentious and unresolved. Nevertheless, there remain further reasons for

questioning Wegner’s argument.

Vaguely Conscious Beginnings in RPReturning to Wegner, at one point in his book he appears to consider a problem in his

argument. Reflecting on Libet’s experiment, he states, “we don’t know what specific

unconscious mental processes the RP might represent.”10 Intuitively, it seems that knowledge

7 Libet, 1985: 5378 Ibid. 5389 Recently, a group of neuroscientists attempted to show that the act of conscious inhibition is also an illusory by-product of unconscious neuronal activity (Filevich et al., 2013).

10 Wegner, 2002: 55

4

of what RP represents would be essential to arguments that take RP as evidence against free

will. Nevertheless, despite any apparent misgivings, Libet and his experiment remain

centerpieces in Wegner’s book.11 The problem that Wegner alludes to, however, is a very real

one: Libet’s experiment tells us that something is happening prior to consciousness, but it

does not tell us what exactly that might be.

This brings us to a further challenge. Insofar as Wegner’s argument is based in Libet’s

experiment, if he is to assert that conscious willing does not lead to action he must argue that

RP is not a conscious process. However, this may not be the case. It has been suggested since

Wundt’s experiments in the mid nineteenth century that there are antecedents to complete

conscious awareness. From his early experiments, Wundt developed a theory of mind that

distinguished between two modes of cognition: apperception and perception. Perception, he

theorized, is a passive and automatic process,12 which allows one to perform quick reflexive

movement, like swerving a vehicle away from an oncoming motorist. Contrarily,

apperception “is active and voluntary,” that is, under the conscious control of the individual.13

Of course, while these two modes of cognition have their own distinguishing features, they

are not actually separable. Philosopher Kim Alan explains their relationship thusly:

Consciousness [in Wundt’s view] is a function of the scope of attention, which may be

broader (as perception) or narrower (as apperception). Apperception, in turn, may

either actively select and focus upon a perceived representation, or it may passively

find certain representations suddenly thrusting themselves into the center of attention

[…] perceptive attention becomes apperceptive attention just as it focuses more

strenuously, constricting the perceptive field.”14

11 Holton, 2004: 21912 Hergenhan et al., 2013: 25313 Ibid. 25314 Kim, 2014

5

Suppose you are sitting at a desk writing a paper. Although you may be intently focused on

crafting each sentence, there remain a number of sensations in your broad perceptual field that

you are largely unaware of (your ears are hearing, your skin is sensing the temperature, etc.).

Yet, vague awareness gives way to a state of crisply defined conscious attention. For example,

a loud sound may cause one’s conscious focus to quickly shift. With reference to Wundt’s

theory of mind, it seems reasonable to suggest that Libet’s W may represent solely that point

in time at which one becomes crisply conscious of the intention to act. In other words, crisply

defined conscious experience, or W, may have vaguely conscious beginnings in RP. If this is

the case, then Libet’s results, which purportedly show consciousness as a neurological

latecomer, might not be so shocking. As to why Libet’s subjects did not report any conscious

experience prior to W, it may be the case that semi-conscious mental events, being naturally

vague, are difficult to pin down or, quite simply, that they were never asked for.15

The Conscious Pre-Planning StageLet us now move on to our final challenge. If Wegner is to successfully claim that conscious

willing does not lead to action, he must necessarily argue that not only is W epiphenomenal

and RP unconscious, but that consciousness, wherever it may appear in the events leading to

action, is always epiphenomenal. Yet, Libet’s experiment only gives us a brief look at the

immediate antecedents of action. Indeed, examining Libet’s experiment in isolation, it seems

we have very little room to account for conscious processes outside of the period of time

where the subject is already wired into the experiment.

The possibility that causally significant conscious processes precede RP should not be

discounted outright. According to German psychologist Narciss Ach, habitual action is the

end result of a two stage process: (1) during a general conscious planning stage, an individual

consciously adopts a goal, (2) setting in motion a chain of largely unconscious processes that

15 Sheerer, 1985: 553

6

ultimately produce the action.16 Here, an example may help to clarify. Having consciously

chosen to drive to a nearby store, a learned driver may make the trip barely aware of the

complex manoeuvres they are accomplishing (turning the wheel, moving the foot from the

pedal to the break, shifting gears, etc.). They may even be able to have a conversation with a

passenger or become so engrossed in their thoughts that they hardly notice the passing

scenery. With repeated performance, behaviour, like driving, becomes increasingly

automated, and this is generally for good reason.17 To see this, simply replace the experienced

driver with one who is learning to drive. Unlike their learned counterpart, the novice driver

has a number of things to think about: the vehicle’s speed; how to turn the steering wheel; that

mirrors are checked every so often. The strain on their cognitive processes may prove so great

that they barely notice street signs or the traffic ahead. Having largely committed the act of

driving to the realm of habit, the experienced driver is generally free from the cognitive stress

of the novice, and yet their actions remain inextricably linked to conscious processes. Indeed,

according to Ach, it was conscious processes that ultimately set them in motion.

Now recall Libet’s experiment. One can imagine a point in time at which Libet explained to

his subjects the task he wished them to perform. At this time, the decision to move one’s right

hand could have been consciously determined, setting in motion a largely unconscious chain

of processes (hand moving being an action learned to the point of unconscious habit) that

ultimately led to the act. Of course, being that Libet’s experiment only provides a small

window into the moment immediately prior to action, we do not know what precedes RP, but

we do know that Ach’s model is entirely consistent with the results as they are presented. For

Ach’s model to be correct we do not need a conscious RP. We solely need a conscious

process, which is not accounted for in Libet’s experiments, to set the chain of events in

motion.

16 Sheerer, 1985: 55317 Wheatley & Wegner, 2001: 991

7

ConclusionConsidering the challenges posed, it seems Libet’s experiment does not provide the necessary

groundwork for Wegner to advance his case against free will. Indeed, not only might W have

causal significance, RP may coincide with a state of vague conscious awareness. Moreover,

because Libet’s experiment is narrow in scope, it is impossible to claim on its basis alone that

consciousness is always epiphenomenal, which Wegner’s argument seems to require. In fact,

as Ach suggests, it may be the case that consciousness sets behaviour in motion during a

general planning stage, which Libet’s experiment does not account for. Taken as a whole, the

examination provided should remind those of us engaged in the free will debate that we ought

to consider the long-term planning capabilities of the human brain and, likewise, that

consciousness may not be sudden or omnipresent, but a fluid process, that develops out of a

state of vague awareness. On these grounds, Libet’s experiment provides very little insight.

Thus, until further experiments are conducted and theories like those presented are rejected it

is premature to classify free will an illusion as Wegner does.

8

BibliographyBayne, T. (2011). Libet and the case for free will scepticism. In R. Swinburne (Ed.), Free Will

and Modern Science (pp. 25-46). Oxford: Oxford University Press.

Danziger, K. (2001). The Unknown Wundt: Drive, Apperception, and Volition. In R. W.

Rieber, & D. Robinson (Eds.), Wilhelm Wundt in History: The Making of a Scientific

Psychology (pp. 95-120). New York, NY: Plenum Publishers.

Filevich, E., Kühn, S., & Haggard, P. (2013). There Is No Free Won’t: Antecedent Brain

Activity Predicts Decisions to Inhibit. PLoS ONE, 8 (2).

Haggard, P. (2008). Nature Reviews Neuroscience. Nature Reviews Neuroscience, 9

(12), 934-946.

Haggard, P., & Eimer, M. (1999). On the Relation Between Brain Potentials and the

Awareness of Voluntary Movements. Experimental Brain Research, 126 (1), 128-133.

Harris, Sam. (2012). Free Will. New York, NY: Free Press

Hergenhahn, B. R., & Henly, T. (2013). An Introduction to the History of Psychology (7 ed.).

Belmont, CA: Cengage Learning.

Holton, Richard. (2004). The Illusion of Conscious Will by Daniel Wegner. Mind, 113 (449),

218-221.

Hommel, B. (2003). Planning and Representing Intentional Action. The Scientific

World, 593-608.

James, W. (1981). The Principles of Psychology (Vol. II). Cambridge, MA: Harvard

University Press.

John Templeton Foundation. (2010). Finding Free Will. Retrieved October 25, 2014 from

templeton.org: http://www.templeton.org/what-we-fund/funding-priorities/finding-

free-will

Keller, I., & Heckhausen, H. (1990). Readiness Potentials Preceding Spontaneous Motor

9

Acts: Voluntary vs. Involuntary Control. Electroencephalography and Clinical

Neurophysiology, 76 (4), 351-361.

Kim, A. (2014). Wilhelm Maximilian Wundt. (E. N. Zalta, Ed.) Retrieved October 31, 2014

from he Stanford Encyclopedia of Philosophy:

<http://plato.stanford.edu/archives/spr2014/entries/wilhelm-wundt/>

Lau, H. C., Rogers, R. D., Haggard, P., & Passingham, E. R. (2004). Attention to Intention.

Science, 303 (5661), 1208-1210.

Libet, B. (1985). "Unconscious Cerebral Initiative and the Role of Conscious Will in

Voluntary Action. Behavioral and Brain Sciences, 8 (4), 529-539.

McCrone, J. (2001). Going Inside: A Tour Round a Single Moment of Consciousness. New

York: Fromm International.

Schmidgen, H. (2003). Time and noise: the stable surroundings of reaction experiments,

1860–1890. Studies in History and Philosophy of Science Part C: Studies in History

and Philosophy of Biological and Biomedical Sciences, 34 (2), 237-275.

Sheerer, E. (1985). Conscious Intention is a Mental Fiat. Behavioral and Brain Sciences, 8

(4), 552-553.

Soon, C. S., Brass, M., Heinze, H.-J., & Haynes, J.-D. (2008). Unconscious Determinants of

Free Decisions in the Human Brain. Nature Neuroscience, 11 (5).

Teo, T. (2000). Narziß Ach. In A. Kazdin (Ed.), Encyclopedia of Psychology (Vol. 1, pp.

24-25). New York, NY: Oxford University Press.

Trevena, J., & Miller, J. (2002). Cortical Movement Preparation Before and After a

Conscious Decision to Move. Consciousness and Cognition, 11 (2), 162-190.

Wegner, D. (2002). The Illusion of Conscious Will. Cambridge, MA: MIT Press.

Wheatley, T. P., & Wegner, D. M. (2001). Automaticity in Action. In N. J. Smelser, & P. B.

10

Paul (Eds.), International Encyclopedia of the Social & Behavioral Sciences (pp. 991-

993). London: Elsevier Science Ltd.

11