What Is Free Will and Does It Exist?

I stood upon the sec­ond of three grad­u­ated plat­forms, each dis­play­ing the work of a dif­fer­ent artist. Between the messy, and often graf­fi­tied, por­traits I found a face famil­iar to me. One I did not expect. It was a Fri­day evening; in the after­noon I had jour­neyed to UC Berke­ley to con­sult a cer­tain Guy Isely, who will be dis­cussed later, after­ward I crossed the heart of the cam­pus and dove into the Berke­ley Art Museum to attend their weekly L@te event. The exhibits remain open long after nor­mal clos­ing time, and live, often exper­i­men­tal, music is played. I did not expect that any of my peers had made the same jour­ney, that they would be in the same place, and that we would briefly gaze at the same pic­ture. But it hap­pened, and, as the boy was but an acquain­tance, we were com­pelled to make the small­est of talk: that about activ­i­ties in which we know the other is engaged. The month being what it was, senior project was the obvi­ous choice. I told him that I was inves­ti­gat­ing free will from a neu­ro­log­i­cal per­spec­tive. After a brief spar in which he defended our free­dom, he paused, then said, “well, we’re hav­ing this con­ver­sa­tion, so that’s good enough for me.” I frowned. Free will is an oft assumed attribute of the human race, our con­scious­ness leads us to believe in it. The actions of oth­ers lead us to believe in it. But we must not always fol­low our lead­ers blindly.

Free will shall be defined for the pur­poses of this paper as fol­lows: a uniquely human char­ac­ter­is­tic that allows a con­scious­ness to dis­re­gard all inter­nal and exter­nal influ­ences to make deci­sions based purely on whim. In fact, free will, at its base, sim­ply claims that human­ity main­tains a con­sis­tent capac­ity for com­plete ran­dom­ness. Dr. Wal­lis, who will be dis­cussed in greater depth deeper in this paper, asked me for my def­i­n­i­tion in response to my request that he give his; so, I deliv­ered the above. He seemed to think for a moment, and agreed that it was an apt one. It is with his vin­di­ca­tion that I pro­ceed. Free will is often defined as a human’s abil­ity to inde­pen­dently make a per­sonal choice, how­ever, such def­i­n­i­tions do not deign to define in what parts a per­sonal pref­er­ence is deter­mined by atmos­pheric fac­tors. In our def­i­n­i­tion, we have avoided such con­fu­sion. I am ask­ing whether or not our con­scious­ness is capa­ble of con­tra­dict­ing all that our fab­ric inclines us toward. That is true free­dom. Any dilu­tion dic­tat­ing that our inter­est be adhered to is an illu­sion – it is not suited to the term we throw casu­ally from our lips: free will.

In Leo Tolstoy’s novel Anna Karen­ina, the char­ac­ter Levin says that, “my rea­son will… not under­stand why I pray, but I will still pray, and my life, my whole life, inde­pen­dently of any­thing that may hap­pen to me, is every moment of it no longer mean­ing­less as it was before.” His belief in God repli­cates my belief in free will. It has enjoyed the sta­tus of a the­o­rem, with­out any rigor in its estab­lish­ment. And as sci­en­tific and philo­sophic evi­dence begins to ques­tion its integrity, I realise more poignantly the implicit faith with which I have accepted it.
I now set out to test that faith.

For thou­sands of years, deter­min­ism was assumed. Our sov­er­eignty was offered up to deity after deity for use in con­struct­ing a great cos­mic order. In his text The Ori­gin of Con­scious­ness in the Break­down of the Bicam­eral Mind Julian Jaynes demon­strates that the writ­ings and cus­toms of ancient cul­tures fail to attribute any mean­ing­ful voli­tion to their con­stituents. Instead, Jaynes posits that most of ancient man’s actions resulted from the brain’s trans­mis­sion of instruc­tions via audi­tory and some­times visual hal­lu­ci­na­tions. Ancient man had not even con­scious­ness to con­found our esti­ma­tion of his free­dom. But even after our most impor­tant attribute arose, man scarcely asserted that he was free. New­ton­ian physics fur­ther dis­cour­aged such a con­clu­sion, cod­i­fy­ing that all effects have a con­crete cause – to assume free will would be to assume a ball can choose to quit rolling. Our bio­log­i­cal sys­tems must mir­ror the phys­i­cal sys­tems that sur­round us. How­ever, proofs based on Newton’s laws, often used to show the neces­sity of God, assert­ing that an ‘unmoved mover’ must exist, hinted toward the idea that, per­haps, our con­scious­ness is an ‘unmoved mover’ itself – a free agent.

The writ­ings of Soren Kierkegaard, Friedrich Niet­zsche, Fyo­dor Dos­to­evsky, Mar­tin Hei­deg­ger and oth­ers through­out the nine­teenth and twen­ti­eth cen­turies would even­tu­ally crys­tal­lize into one of the most main­stream philo­soph­i­cal move­ments to ever hold free will as part of its foun­da­tion: exis­ten­tial­ism. The French philoso­pher Jean-Paul Sartre, one of its pri­mary advo­cates and aggre­ga­tors, wrote of the absur­dity man expe­ri­ences when con­fronted by his absolute free­dom as a result of the world’s absolute lack of inher­ent mean­ing. He termed it a sort of nau­sea. In a novel by the same name, the pro­tag­o­nist sud­denly finds him­self respon­si­ble for con­struct­ing his own mean­ing, a theme Sartre explores fur­ther in his mas­sive philo­soph­i­cal tome Being and Noth­ing­ness. Sartre empha­sizes human aloof­ness from from phys­i­cal causal­ity, and, in that way, entirely rejects deter­min­ism. Sartre’s phi­los­o­phy quickly became fash­ion­able, though he always main­tained that it was a school of thought “strictly intended for spe­cial­ists and philoso­phers.” As a con­se­quence of its pop­u­lar­ity, it became mas­sively dis­torted, and even vil­i­fied. In response, Sartre abridged his thought into a lec­ture enti­tled “Exis­ten­tial­ism is a Human­ism” which reaf­firmed his belief in our absolute free­dom, but also plainly offered the worldly anchors that many crit­ics per­ceived the sys­tem to lack. Exis­ten­tial­ism has remained the fash­ion­able choice of teenagers with nihilis­tic ten­den­cies ever since, though they often gloss over much of the respon­si­bil­ity that Sartre underlines.

Mem­o­ries of myself as a fash­ion­able teenager with nihilis­tic ten­den­cies aside, the main bat­tery that I shall direct against our idea of a free will is not phi­los­o­phy, but rather behav­ioral, or social, neu­ro­science. John Cacioppo, a pio­neer of the field, recalls the ori­gin of his spe­cialty, “there was a lot of skep­ti­cism among neu­ro­sci­en­tists about study­ing any­thing out­side the cra­nium. Twentieth-century neu­ro­science thought social behav­ior was just too com­plex to study.” (Gole­man) Now, neu­rol­o­gists have mean­ing­fully mapped many of the regions of the brain involved in social inter­ac­tions. There is still much mys­tery, and many neu­ro­sci­en­tists fall short of unequiv­o­cally renounc­ing free will, but the fur­ther our thoughts are sci­en­tif­i­cally sys­tem­atized the more irra­tional and mys­tic an inde­pen­dent voli­tion appears.

Guy Isely, a researcher at UC Berkeley’s Red­wood Cen­ter for The­o­ret­i­cal Neu­ro­science, agreed to speak with me about the ques­tion of free will and how it relates to his stud­ies. I jour­neyed, one rainy Fri­day, to his office, inside of another office, on the fifth floor of Evans Hall. The Cen­ter seemed to occupy most of the floor, and research posters with suf­fixes longer than pi pat­terned the walls. As the­o­ret­i­cal neu­ro­science is a com­pu­ta­tion­ally inten­sive field, I was not sur­prised to note that Mr. Isely’s desk alone had three sep­a­rate com­put­ers, all inces­santly used. We left Guy’s office and walked quickly to the con­fer­ence room, wherein the table was strewn with paper – half aim­less doo­dles and the other half com­plex math­e­mat­ics. Though Cacioppo now directs an insti­tute at the Uni­ver­sity of Chicago and Berke­ley itself has an expan­sive umbrella insti­tute for social neu­ro­science, the field is still devel­op­ing. Mr. Isely wrote sheep­ishly to me before our meet­ing, that “there’s not much to see [at the Red­wood Cen­ter] other than some offices and some research posters– that’s what a the­o­ret­i­cal group looks like I guess.“ Even so, the work done has enor­mous impli­ca­tions for how we, as humans, under­stand our own actions and the actions of others.

Though Mr. Isely does not explic­itly inves­ti­gate the ques­tion of free will – rather, the brain’s meth­ods of recog­nis­ing and react­ing to the low-level sta­tis­ti­cal prop­er­ties of per­ceived objects – his gen­eral knowl­edge of our men­tal mech­a­nisms and his back­ground as an under­grad­u­ate phi­los­o­phy major allowed him to address my ques­tions with author­ity. He defined free will sim­ply as the abil­ity to say, “I do what I want to do.” And went on to assert that, in the con­text of that def­i­n­i­tion, free will is both exis­tent and desir­able; in the con­text of my def­i­n­i­tion, he was less clear about its exis­tence and found that such an abil­ity would not be in our inter­est. He said that he liked the feel­ing of secu­rity that know­ing he was act­ing toward his goals gave him. We did also come into an inter­est­ing dis­cus­sion about neu­ro­pl­a­sitic­ity: the man­ner in which it affects our per­cep­tion, and its con­se­quences for human behav­ior. Before I begin to dis­cuss that, how­ever, I feel that I owe my gra­cious reader a wee bit of back­ground about the brain.

Our most ele­vated organ trans­mits infor­ma­tion through a com­bi­na­tion of elec­tri­cal and chem­i­cal sig­nals emit­ted by small cells called neu­rons. There are three main types of neu­rons: sen­sory neu­rons, which bring infor­ma­tion to the cen­tral ner­vous sys­tem; interneu­rons, which asso­ciate infor­ma­tion within the cen­tral ner­vous sys­tem; and motor neu­rons, which send infor­ma­tion from the brain and spinal cord to the mus­cles. Neu­rons com­mu­ni­cate by ‘fir­ing,’ or releas­ing a neu­ro­trans­mit­ter into the synap­tic cleft – the space between neu­rons – through a process called action poten­tial that is prop­a­gated by changes in the chem­i­cal con­cen­tra­tions within and with­out the cell itself. The released neu­ro­trans­mit­ter enters a spe­cific bind­ing site in the recep­tors of a nearby neu­ron, in which it aids or inhibits fur­ther fir­ing. Action or inac­tion gen­er­ally result from enor­mous cas­cades of neu­ronal activity.

The vari­ety of neu­ro­trans­mit­ters and net­works into which they are released com­pose the major­ity of our brain’s com­mu­ni­ca­tion with our body and with itself. That com­mu­ni­ca­tion causes bouts of depres­sion and of ecstasy. It causes invol­un­tary reac­tions and our inten­tional actions. A com­pre­hen­sive assess­ment of the brain and its func­tions seems not to leave room for a free will. The brain receives input and pro­duces out­put. The frontal regions act as our exec­u­tive, and make pro­jec­tions toward the future; the pari­etal lobe inte­grates the sen­sory infor­ma­tion from our mul­ti­ple modal­i­ties, then asso­ciates that infor­ma­tion with mem­o­ries and with our present inter­nal state; the tem­po­ral lobe holds mem­o­ries, iden­ti­fies items, processes audio, and expe­ri­ences emo­tion. (Banich) As Tom Stop­pard writes in his play Rock ‘n’ Roll, “[The] mind is [the] brain… if it wasn’t for the merely tech­ni­cal prob­lem of under­stand­ing how it works, we could make one out of – beer cans. It would be the size of a sta­dium but it would sit there, going, ‘I think there­fore I am.’”

Even in social inter­ac­tions, map­ping of the brain has revealed a con­certed sys­tem of cause and effect. The fir­ing of one neu­ron quickly fol­lowed by the fir­ing of an adja­cent neu­ron makes the con­nex­ion between those two neu­rons more effi­cient. It is hypoth­e­sized that such an increase in effi­ciency is the cel­lu­lar basis of learn­ing – not sim­ply learn­ing facts, but also behav­iors and rela­tion­ships. (Hunt) The effi­cien­cies cre­ated between neu­rons can lead to long term social attach­ments or even addic­tive habits. They can cre­ate depen­den­cies that cause us to per­pet­u­ate a cer­tain behav­ior long after it has become destruc­tive. (Gole­man) This phe­nom­e­non is known as neu­ro­pl­a­sitic­ity. Daniel Gole­man writes that “our social inter­ac­tions… play a role in reshap­ing our brain… repeated expe­ri­ences sculpt the shape, size, and num­ber of neu­rons and their synap­tic con­nex­ions. By repeat­edly dri­ving our brain into a given reg­is­ter, our key rela­tion­ships can grad­u­ally mold cer­tain neural circuitry.”

Dur­ing my search for an ivory home next year, I inter­viewed with a clin­i­cal psy­chol­o­gist mas­querad­ing as a Yale Uni­ver­sity alumni. In the course of our con­ver­sa­tion I men­tioned that I would most likely major some­where within the cog­ni­tive and brain sci­ences, which tum­bled us into a dis­cus­sion about the impli­ca­tions of neu­ro­plas­tic­ity for clin­i­cal psy­chol­ogy. He told me that it was absolutely some­thing con­sid­ered by him and his peers. In my con­ver­sa­tion with Guy Isely as well, neu­ro­plas­tic­ity was found to be very impor­tant for my ques­tion, but also for all ques­tions about the phys­i­o­log­i­cal mech­a­nisms of the mind. Mr. Isely told me that the world appears fun­da­men­tally dif­fer­ent to those that have not devel­oped effi­cient rep­re­sen­ta­tions of objects through neu­ro­plas­tic­ity. This should not be sur­pris­ing when we recog­nise that our mind fills in minor gaps almost all the time. In his phe­nom­e­no­log­i­cal essay The Imag­i­nary Jean-Paul Sartre writes that, when we first see an object we “make a hypoth­e­sis that the later course of [our] per­cep­tions may oblige [us] to aban­don,” because we see it only from one point of view. “One must learn objects, which is to say, mul­ti­ply the pos­si­ble points of view on them. The object itself is the syn­the­sis of all these appearances.”

The ana­logue from the for­mer to the present topic – that is, to the ques­tion of free will – is, per­haps, made most elo­quently by a philoso­pher that was active just under three hun­dred years before neu­ro­plas­tic­ity became an accepted pre­cept, David Hume. He asserted that an “idea of nec­es­sary con­nex­ion among events arises from a num­ber of sim­i­lar instances… [and that] the mind is car­ried by habit, upon the appear­ance of one event, to expect its usual atten­dant, and to believe that it will exist.” Hume writes that “the most irreg­u­lar and unex­pected res­o­lu­tions of men may fre­quently be accounted for by those, who know every par­tic­u­lar cir­cum­stance of their char­ac­ter and sit­u­a­tion.” That is, if one is aware of all the vari­ables, the actions of a man may pre­cisely be antic­i­pated. And “it is uni­ver­sally allowed, that noth­ing exists with­out a cause of its exis­tence,” includ­ing thoughts. He goes on to refute the idea of free will based on rea­son because “[cus­tom] alone deter­mines the mind, in all instances, to sup­pose the future con­formable to the past. How­ever easy this step may seem, rea­son would never be able to make it.”

Dr. Jonathan Wal­lis of Berkeley’s Wal­lis Lab­o­ra­tory and Helen Wills Neu­ro­science Insti­tute has been lead by his work, in the neu­ro­log­i­cal under­pin­nings of behav­ior, to almost the exact same con­clu­sions as David Hume – though he admits to hav­ing never read the man’s work. Dr. Wal­lis began our inter­view briskly with the asser­tion that there is absolutely no sci­en­tific basis for a belief in free will unless we posit some­thing non-physical, some­thing super­nat­ural. He described the process our mind goes through as it makes a deci­sion as “mul­ti­ple sys­tems all com­pet­ing for con­trol of behav­ior,” he also men­tioned that the process is essen­tially the same in lower level ani­mals as it is in humans. The brain’s neu­rons encode deci­sions, and they do so based on a vari­ety of input and inter­nal vari­ables: “the brain,” Wal­lis said, “is a sys­tem. As we learn more about the human brain we grow more skilled at pre­dict­ing behav­ior.” Game The­ory in Eco­nom­ics and cer­tain branches of Psy­chol­ogy espe­cially tes­tify to that fact. Noth­ing is truly ran­dom, occa­sion­ally events sim­ply appear to be, due to gaps in our knowl­edge. Accord­ing to Wal­lis, any unac­count­able vari­a­tion we dis­cover can be cured by exhaus­tively research­ing the spec­trum of pos­si­ble influ­ences. Yet, even the most com­pre­hen­sive research will likely fall short: the brain has more pos­si­ble unique states than the uni­verse has atoms. Stud­ies of deci­sion mak­ing can only hope to account for major influ­ences – the rest will appear as ran­dom behav­ioral noise, which will be touched upon later.

An arti­cle in the sci­en­tific jour­nal Nature writ­ten by Patrick Hag­gard of Uni­ver­sity Col­lege Lon­don fur­ther out­lines the pro­ce­dure of deci­sion mak­ing. “Voli­tion is… a set of processes, [that] jointly spec­ify sev­eral kinds of infor­ma­tion… vol­un­tary action is a form of deci­sion mak­ing.” The brain first must mar­shal the moti­va­tions for action; then, it selects a task and an action that would com­plete that task; before act­ing, the brain rechecks its moti­va­tions and often mod­els the future as affected by the pro­posed action; finally, the brain causes the action. The arti­cle lists four com­pu­ta­tional prin­ci­ples that lead to vol­un­tary action. First, “vol­un­tary action as exploratory behav­iour,” seen to be one of the great­est boons of our men­tal processes because “an animal’s suc­cess depends [in part] on… explor­ing pos­si­ble new resources through new actions.” Sec­ond, “vol­un­tary action as ran­dom behav­ioral noise,” that is, “small… vari­a­tions… which pro­duce one result rather than another.” Third, “vol­un­tary action as con­di­tioned respond­ing,” in uncer­tain sit­u­a­tions tak­ing the course that has pre­vi­ously proven suc­cess­ful. And fourth, “vol­un­tary action as goal directed-ness,” action prompted by the expected out­come of the action. Our con­scious­ness is seen to sim­ply pre­dict our action and recon­struct the moti­va­tion behind that action to com­pose a sense of “vol­un­tary con­trol.” It is not an active com­po­nent of deci­sion mak­ing mod­els, as Dr. Wal­lis attested.

Else­where, the arti­cle dis­cusses a famous exper­i­ment on free will, in which “par­tic­i­pants watch a spot or clock rotat­ing on a screen. At a time of their own choos­ing they spon­ta­neously make a move­ment of their right hand… the par­tic­i­pants report when they first ‘felt the urge’ to move their hand.” The exper­i­ment found that par­tic­i­pants would report the con­scious inten­tion to act only mil­lisec­onds before tak­ing the action, but even more inter­est­ingly the brain showed prepa­ra­tion for the action a whole sec­ond before the inten­tion was reported. Though the exper­i­ment, orig­i­nally per­formed by Bejamin Libet of UCSF, has been widely repli­cated, it still finds harsh crit­i­cism. Two major issues that have been raised are that “the real vol­un­tary action is the participant’s deci­sion to join the exper­i­ment… and… that sub­jec­tive esti­mates of when con­scious expe­ri­ences occur are unre­li­able… the brain fre­quently man­u­fac­tures con­scious expe­ri­ences after the event, retro-inserting them into the stream of con­scious­ness.” Despite the crit­i­cism, Libet’s exper­i­ment “seems to dis­prove the every­day con­cept of ‘free will.’”

Often we are told that if free will does not exist we, as con­scious beings, can­not be made respon­si­ble for our actions. How could we, let us say, jail some­one for tak­ing an action that they did not con­sciously choose to take? In fact, the actions we do not choose are the only actions for which we can be pun­ished. David Hume wrote, “actions are, by their very nature, tem­po­rary and per­ish­ing; and where they pro­ceed not from some cause in the char­ac­ter and dis­po­si­tion of the per­son who per­formed them, they can nei­ther redound to his hon­our, if good; nor infamy, if evil.” So, if our will is free, then our actions have no con­crete cause within us, and thus we can­not be blamed for them. Yet, if our will is sys­tem­at­i­cally deter­mined then our actions do pro­ceed from causes entirely within us, and thus we can be blamed – for it is rea­son­able to expect sim­i­lar actions in the future given sim­i­lar cir­cum­stances. Only in deter­min­ism can we jus­tify the jail­ing of an indi­vid­ual on a pre­ven­ta­tive basis. Daniel Den­nett of Tufts Uni­ver­sity writes that “causal­ity [is] what makes us moral agents,” not free­dom. (Overbye)

In – admit­tedly tan­gen­tial – con­nec­tion with this project, I spent six days roam­ing the Ven­tana Wilder­ness in soli­tude. Near the end of that period, I wan­dered into the bosom of a Zen Monastery nes­tled therein. My arrival came as morn­ing touched noon, so I sat in for lunch and washed it down by wash­ing win­dows to earn a bed for that evening. Between work and din­ner I occa­sioned upon one of the monks, who agreed to speak with me about my ques­tion. We removed our­selves to seat­ing on a wooden bridge gar­nished with the white noise of water whet­ting stone. To my ques­tions the wrin­kled, bald monk had only one answer: it does not mat­ter. There is an absolute real­ity, sure. But it is unlikely that we will ever know it. We must make due with the con­ven­tional real­ity that we are fed. The Bud­dha taught a ces­sa­tion of suf­fer­ing, noth­ing more. We must work toward com­fort and com­pla­cency – and cer­tainly not actively seek uncer­tainty, enough accosts in our reg­u­lar course. My ques­tion has no prac­ti­cal aspect. It is an entirely vac­u­ous ven­ture. I will admit, her response did some­what shock me. And as I reeled from it, she fol­lowed with a direct jab, her worn face inclined toward mine to ensure her voice would super­sede the back­ground: “Why does it mat­ter to you?”

For a moment, I did not know how to answer. My chalk­board, usu­ally so wildly adorned, was washed – and while all the chalk remained, it took no def­i­nite form. I recov­ered, but I think she saw the process through my lenses. It does truly mat­ter to me, in the macro and micro of my mind. I answered: it mat­ters to me because it is one of my assump­tions; also, it shall affect my adop­tion of assump­tions in the future. Fur­ther, it would be suf­fer­ing for me to con­tinue with­out hav­ing tested all of my assump­tions. I work to cede my anguish, sim­ply in a dif­fer­ent way. I could not read her face, but maybe what I said was lost in the space between my mind and her ears. We adjourned. At least she had not offered some vague tes­ta­ment about ‘such­ness,’ as two ludic women with which I had spo­ken of my plan warned she might. Her ques­tion caused me to briefly inspect mine from the out­side: to deter­mine its worth. In one of my classes, the teacher often tran­scribes quotes on an unused cor­ner of the main board. One day the quote, author anony­mous, read roughly that, “A great mis­take edu­ca­tors often make is assum­ing that all knowl­edge must be for some prac­ti­cal use.” A lull in the instruc­tion allowed a peer and me to dis­cuss it briefly, we con­cluded that we would have writ­ten it thus, “A great mis­take edu­ca­tors often make is assum­ing that any knowl­edge can have no prac­ti­cal use.” So, despite my question’s lack of imme­di­ate prac­ti­cal­ity, I reaf­firmed and jus­ti­fied my interest.

From all the pre­ced­ing, I feel I must make a con­clu­sion. So, I shall. As I have defined it, free will does not exist. Yet, Stop­pard writes, the brain “does love. It does inspi­ra­tion. It does mem­ory. It does thought.” I am still inti­mately respon­si­ble for myself. Per­haps, more so than I would be if I con­cluded con­versely. I act in my own inter­est, and if my con­scious­ness be only an observer, my char­ac­ter is one that suf­fers an exquis­ite nar­ra­tion – I am quite wrapped in my story, as I see it made; though, in moments that I do reflect, I despair of my detach­ment from it. Like the UN, with­out weapons, sim­ply observ­ing for­eign­ers at war. I hold some hope that my con­clu­sion is incor­rect, I know that I can­not have exhausted the topic entirely. I know that there are stones I have left unturned – ones with wells beneath. So I shall keep search­ing, shall keep ques­tion­ing. I will appre­hend that absolute real­ity, if it can be brought within the scope of our Euclid­ean conception.

Works Cited and Consulted

Print.

• Banich, Marie T. Cog­ni­tive Neu­ro­science and Neu­ropsy­chol­ogy. Boston: Houghton Mif­flin, 2004. Print.
• Dayan, Peter, and L. F. Abbott. The­o­ret­i­cal Neu­ro­science: Com­pu­ta­tional and Math­e­mat­i­cal Mod­el­ing of Neural Sys­tems. Cam­bridge, Mass.: MIT, 2001. Print.
• Gole­man, Daniel. Social Intel­li­gence: the New Sci­ence of Human Rela­tion­ships. New York: Ban­tam, 2006. Print.
• Hag­gard, Patrick. “Human Voli­tion: towards a Neu­ro­science of Will.” Nature 9 (2008): 934–46. Print.
• Hume, David. An Enquiry con­cern­ing Human Under­stand­ing. Indi­anapo­lis, Ind. [u.a.: Hack­ett, 1995. Print.
• Hunt, Earl B. The Math­e­mat­ics of Behav­ior. Cam­bridge: Cam­bridge UP, 2007. Print.
• Jaynes, Julian. The Ori­gin of Con­scious­ness in the Break­down of the Bicam­eral Mind. Boston: Houghton Mif­flin, 1990. Print.
• Sartre, Jean-Paul. Being and Noth­ing­ness: a Phe­nom­e­no­log­i­cal Essay on Ontol­ogy. New York: Wash­ing­ton Square, 1992. Print.
• Sartre, Jean-Paul. Exis­ten­tial­ism Is a Human­ism. New Haven: Yale UP, 2007. Print.
• Sartre, Jean-Paul. Nau­sea. New York: New Direc­tion, 2007. Print.
• Sartre, Jean-Paul. The Imag­i­nary: a Phe­nom­e­no­log­i­cal Psy­chol­ogy of the Imag­i­na­tion. Lon­don: Rout­ledge, 2004. Print.
• Stop­pard, Tom. Rock ‘n’ Roll. New York: Grove, 2007. Print.
• Tol­stoy, Leo. Anna Karen­ina. New York: Ran­dom House, 1965. Print.

Web.

• Over­bye, Den­nis. “Free Will: Now You Have It, Now You Don’t.” New York Times. 2 Jan. 2007. Web. 25 Mar. 2010.

Inter­views.

• Isely, Guy. Per­sonal inter­view. 2 Apr. 2010.
• Wal­lis, Jonathan. Per­sonal inter­view. 1 Apr. 2010.

• Photo by Bertie Mabootoo / Used with Per­mis­sion