Can neuroscience solve the mystery of consciousness?

Iden­ti­fy­ing what con­scious­ness is has become the Holy Grail of neu­ro­science. But can con­scious­ness be reduced to what can be observed in a lab­o­ra­to­ry? And what ethics should be applied to this new dis­ci­pline, which rais­es the dual hopes of sig­nif­i­cant med­ical advances and sub­stan­tial finan­cial gains? We dis­cuss this with Lau­re Tabouy, a neu­ro­sci­en­tist and ethi­cist who is pur­su­ing a sec­ond PhD in the ethics of neu­ro­science, dig­i­tal tech­nol­o­gy, neu­rotech­nolo­gies and arti­fi­cial intel­li­gence at the Cen­tre Gilles Gas­ton Granger (CGGG UMR 7304) at Aix-Mar­seille Uni­ver­si­ty, dur­ing which she is con­duct­ing a crit­i­cal analy­sis of the neu­roethics imposed by the devel­op­ment of neu­rotech­nolo­gies and the con­ver­gence of neu­ro­science and AI.

Lau­re Tabouy. Con­scious­ness is one of the most com­plex areas of study, falling with­in the scope of both phi­los­o­phy and neu­ro­science, as it encom­pass­es var­i­ous inter­twined dimen­sions: aware­ness of the out­side world and of one­self, the abil­i­ty to reflect on and analyse one’s own thoughts and actions, the source of free will, and the capac­i­ty for moral judge­ment. Since Socrates, it has been one of the major sub­jects of study for philoso­phers and has become a focus for neu­ro­science since the 1960s. Since the 2000s, the con­ver­gence of nan­otech­nol­o­gy, biotech­nol­o­gy, com­put­er sci­ence and cog­ni­tive sci­ence has raised hopes that increas­ing­ly sophis­ti­cat­ed tech­nolo­gies will make it pos­si­ble to iden­ti­fy the phys­i­cal mark­ers of con­scious­ness, and even of reflec­tive con­scious­ness. In par­al­lel with these exper­i­ments on brain activ­i­ty, var­i­ous neu­ro­sci­en­tif­ic the­o­ries known as “the­o­ries of con­scious­ness” have flour­ished in recent decades.

It is a so-called func­tion­al the­o­ry, which is very inter­est­ing from a con­cep­tu­al point of view and is not incon­sis­tent with cer­tain obser­va­tions made in the lab­o­ra­to­ry. It does not describe what con­scious­ness is, but what it does in a per­cep­ti­ble way. Accord­ing to this the­o­ry, the brain func­tions like a the­atre: con­scious thoughts occu­py the front of the stage, also known as the “glob­al work­space”, while in the back­ground, spe­cialised auto­mat­ic process­es locat­ed in the brain are con­stant­ly at work, pro­cess­ing sen­so­ry stim­uli. At any giv­en moment, only the results of some of these process­es are brought into the spot­light, there­by becom­ing acces­si­ble to all the auto­mat­ic neur­al process­es oper­at­ing behind the scenes.

Pro­po­nents of this the­o­ry pos­tu­late that the glob­al work­space is made up of neu­rons with long axons, capa­ble of trans­mit­ting infor­ma­tion to very dis­tant areas of the brain. In their view, the emer­gence of con­scious­ness would there­fore man­i­fest itself through the acti­va­tion of these vast cere­bral networks.

Around thir­ty of them! Of course, not all of them have the same res­o­nance with­in the sci­en­tif­ic com­mu­ni­ty – or in the media and among fund­ing bod­ies. One of the main com­peti­tors to the glob­al work­space the­o­ry is the “inte­grat­ed infor­ma­tion the­o­ry”, pro­posed by Ital­ian neu­ro­sci­en­tist and psy­chi­a­trist Giulio Tononi in 2004. Rather than start­ing from brain activ­i­ty to iso­late the mark­ers of con­scious­ness, it sets out a glob­al the­o­ret­i­cal frame­work of what con­scious­ness is, sup­port­ed by a math­e­mat­i­cal mod­el. This the­o­ry defines con­scious­ness as an emer­gent prop­er­ty of any phys­i­cal struc­ture capa­ble of inte­grat­ing infor­ma­tion, and it applies this def­i­n­i­tion not only to the brain, but also to any infor­ma­tion-pro­cess­ing sys­tem. The degree of con­scious­ness of a sys­tem would thus depend on the amount of infor­ma­tion it is capa­ble of pro­cess­ing and its abil­i­ty to com­pare this infor­ma­tion at dif­fer­ent lev­els, both region­al and global.

Again, this is not incon­sis­tent with what can be observed local­ly in the brain. But it leads pro­po­nents of this the­o­ry to con­sid­er arti­fi­cial sys­tems such as ther­mostats or pho­to­di­odes as “con­scious” – an exten­sion of the con­cept of con­scious­ness about which many neu­ro­sci­en­tists have seri­ous objections.

This the­o­ry has been talked about as much for its nov­el­ty, even provoca­tive­ness, as for the fact that 124 researchers have labelled it pseu­do­science¹ in a preprint (editor’s note: a ver­sion of a sci­en­tif­ic pub­li­ca­tion that pre­cedes its accep­tance by the edi­to­r­i­al board of a sci­en­tif­ic jour­nal) pub­lished on the PsyArX­iv plat­form. How­ev­er, this doc­u­ment remains rather light­weight from a sci­en­tif­ic point of view and is itself high­ly con­tro­ver­sial with­in the neu­ro­science community.

No. A recent col­lab­o­ra­tive study² com­pared the glob­al work­space the­o­ry and the inte­grat­ed infor­ma­tion the­o­ry accord­ing to a pro­to­col estab­lished by a con­sor­tium that claims to be neu­tral in the­o­ret­i­cal terms. Their results con­firm cer­tain pre­dic­tions by both the­o­ries but also call into ques­tion some of their key prin­ci­ples. Ulti­mate­ly, this is not very sur­pris­ing. Neu­ro­science is still a rel­a­tive­ly new aca­d­e­m­ic dis­ci­pline. It has yet to find its inter­nal the­o­ret­i­cal con­ver­gence, and this con­ver­gence will like­ly come about through the com­bi­na­tion of sev­er­al theories.

Pop­u­lar neu­ro­science often takes a reduc­tion­ist approach, mean­ing that it views its sub­ject (con­scious­ness) as the result of sub­sys­tems (brain process­es or the organ­i­sa­tion­al struc­ture of infor­ma­tion, for the two the­o­ries men­tioned). Reduc­tion­ism is not a prob­lem in itself: it allows us to define a frame­work that makes the exper­i­ment pos­si­ble. This is eas­i­ly under­stand­able, giv­en that it already places a prism between us and real­i­ty, through which cer­tain dimen­sions of con­scious­ness may escape.

But the most wide­ly pub­li­cised neu­ro­sci­en­tif­ic the­o­ries – includ­ing, above all, the glob­al work­space the­o­ry and, to a cer­tain extent, the inte­grat­ed infor­ma­tion the­o­ry – are also based on rad­i­cal mate­ri­al­ism: they assume that con­scious­ness can be reduced to phys­i­cal process­es. This is a major philo­soph­i­cal assump­tion, which can – and must – be ques­tioned. It is not itself the result of sci­en­tif­ic con­sen­sus, and phi­los­o­phy, from which it is derived, offers a wealth of alter­na­tive mod­els to explain what con­scious­ness is: ide­al­ism, cer­tain forms of plu­ral­ism, dual­ism (par­tic­u­lar­ly Carte­sian dual­ism), spir­i­tu­al­ism, etc. In fact, there is no rea­son­able basis for defin­i­tive­ly favour­ing a mate­ri­al­ist con­cep­tion of consciousness.

It seems to me to stem from the very con­di­tions in which neu­ro­science itself was born. It was the emer­gence of extreme­ly pow­er­ful tech­nolo­gies for observ­ing brain activ­i­ty that moti­vat­ed its emer­gence. The incred­i­ble effec­tive­ness of these devices has, in a way, blind­ed us: we have con­fused what we are able to see now or will be able to see in the future – which is, indeed, incred­i­bly rich – with real­i­ty as a whole. The search for fund­ing also plays a role in this stance: it is more mar­ketable to say that we are going to get to grips with con­scious­ness than to announce that we hope to make progress in observ­ing some of the phys­i­cal phe­nom­e­na linked to the con­scious activ­i­ty of the brain…

It becomes prob­lem­at­ic when it is con­sid­ered the only way to access the truth of what con­scious­ness is. In this case, it is an ide­o­log­i­cal stance that pro­found­ly dis­torts eth­i­cal debates by cre­at­ing a biased cli­mate for reflec­tion. Based on this mate­ri­al­ist premise, some peo­ple are begin­ning to talk about the pos­si­bil­i­ty of down­load­ing con­scious­ness in the future, for exam­ple. This tran­shu­man­ist ide­ol­o­gy is techno­sci­en­tif­ic in nature and is already steer­ing research, polit­i­cal and finan­cial choic­es in a direc­tion that is high­ly ques­tion­able from an eth­i­cal stand­point. Neu­rotech­nol­o­gy com­pa­nies are clear­ly adopt­ing this bias by announc­ing that they can ‘read your brain’ or ‘deci­pher your brain waves to exploit your unsus­pect­ed abilities’.

The prospect of humans con­trol­ling their own con­scious­ness is so fas­ci­nat­ing that it obscures oth­er press­ing issues. How far are we will­ing to go in arti­fi­cial­ly mod­i­fy­ing the human brain? How can we assess the impact of neu­rotech­nol­o­gy on human evo­lu­tion, and is this where we col­lec­tive­ly want to go? And the ques­tion that dri­ves my the­sis: how can we free neu­roethics from the polit­i­cal and eco­nom­ic tech­noso­lu­tion­ist stran­gle­hold imposed by the devel­op­ment of neu­rotech­nolo­gies and the con­ver­gence of neu­ro­science and AI? It is cru­cial that ethics be a part of this dis­cus­sion, which is not real­ly the case at the moment.

The ethics of neu­ro­science is a recent devel­op­ment: it can be said to have emerged as a branch of ethics in its own right only in 2002, at the San Fran­cis­co con­fer­ence on ‘neu­roethics’. The texts you refer to were writ­ten in the con­text of geopo­lit­i­cal tur­moil asso­ci­at­ed with the launch of huge brain research projects, such as the Human Brain Project⁵ under­tak­en on the ini­tia­tive of the Euro­pean Com­mis­sion and the Brain Ini­tia­tive⁶ launched by the Oba­ma admin­is­tra­tion. These texts are less the result of gen­uine eth­i­cal reflec­tion, ques­tion­ing the foun­da­tions and con­se­quences of ongo­ing tech­no­log­i­cal devel­op­ments, than an attempt to keep pace with these devel­op­ments, dri­ven essen­tial­ly by mar­ket forces.

Dis­sent­ing voic­es exist among philoso­phers, ethi­cists and neu­ro­sci­en­tists them­selves, but they are cur­rent­ly being sti­fled… A gen­uine eth­i­cal reflec­tion must be based on a real philo­soph­i­cal, anthro­po­log­i­cal and cul­tur­al con­tro­ver­sy. It must be borne in mind that West­ern mate­ri­al­ist the­o­ries are far from uni­ver­sal. Beyond the philo­soph­i­cal cur­rents already men­tioned, almost all spir­i­tu­al­i­ties and reli­gions have a non-mate­ri­al­ist view of con­scious­ness. This should prompt us to shift our the­o­ret­i­cal focus. Ethics must also remain inde­pen­dent of the finan­cial inter­ests linked to the tech­no­log­i­cal devel­op­ments it ques­tions. And final­ly, it must keep its focus on the one ques­tion that ulti­mate­ly mat­ters: are these tech­no­log­i­cal devel­op­ments tru­ly serv­ing human­i­ty in all its dimensions?

Interview by Anne Orliac