The matter of the mind: How does it work?

Originally published 27 January 1992

Dear Mr. Ray­mo,
As you may recall, I wrote to you sev­er­al months ago regard­ing the con­nec­tion between quan­tum physics and con­scious­ness. You replied by express­ing skep­ti­cism that the “fuzzi­ness” of the quan­tum world has any­thing to do with the free­dom and cre­ativ­i­ty we asso­ciate with con­scious­ness. If not, then how does physics explain these things?
Sin­cere­ly,
I.M.Curious

Dear I.M.Curious,
Physics does­n’t explain these things. Of course, at some lev­el, every­thing that hap­pens is quan­tum physics. But if and when con­scious­ness is explained it will prob­a­bly be by a com­bined effort of mol­e­c­u­lar biol­o­gists, neu­ro­sci­en­tists, arti­fi­cial intel­li­gence researchers, com­put­er sci­en­tists, and microchip design­ers. So far, we have only hints about what such an expla­na­tion might be, and I sus­pect that nature has a few sur­pris­es in store before con­scious­ness is explained. How­ev­er, if I were a bet­ting man, I would put my mon­ey on com­put­ers — or bet­ter, net­works of inter­con­nect­ed, sep­a­rate­ly pro­grammed com­put­ers — as the most cur­rent­ly use­ful metaphor for human con­scious­ness.
Yours,
Chet Ray­mo

Dear Mr. Ray­mo,
You must be jok­ing. Com­put­ers are not even remote­ly free, and cer­tain­ly not cre­ative. Com­put­ers slav­ish­ly fol­low pro­grams. They mere­ly rearrange. Jug­gle data. I would be exceed­ing­ly sur­prised — and depressed! — to dis­cov­er that my mind was a com­put­er.
Sin­cere­ly,
I.M.Curious

Dear Mr. Curi­ous,
Since our last cor­re­spon­dence a fine book has appeared by Daniel Den­nett, direc­tor of the Cen­ter for Cog­ni­tive Stud­ies at Tufts Uni­ver­si­ty, called Con­scious­ness Explained. Den­nett is a philoso­pher well-versed in psy­chol­o­gy, neu­ro­science, and com­put­er sci­ence. He believes the com­put­er is a sat­is­fac­to­ry metaphor for mind, and he pro­vides a sce­nario for how the mind’s hard­ware and soft­ware might have evolved. The auda­cious­ness of his title far out­strips the sub­stance of his argu­ment. Nev­er­the­less, Den­net­t’s book sug­gests an out­line of how con­scious­ness might one day be explained, mate­ri­al­is­ti­cal­ly and mech­a­nis­ti­cal­ly. It makes com­pelling read­ing.
Yours,
Chet Ray­mo

Dear Mr. Ray­mo,
Whoa! “Mate­ri­al­is­ti­cal­ly and mech­a­nis­ti­cal­ly”? No way am I ready to admit that my mind is just a bunch of sil­i­con chips or clock­work gears. Show me a com­put­er with self aware­ness! Show me a com­put­er that is even remote­ly con­scious! I will admit that con­scious­ness has some­thing to do with the brain, but sure­ly the mind is more than a mere machine.
Sin­cere­ly,
I.M.Curious

Dear I.M.Curious,
Per­haps you have out­dat­ed notions of what mat­ter and mech­a­nism mean. In mod­ern physics, mat­ter has become a thing of mar­velous sub­tle­ty and poten­tial­i­ty. As we probe mat­ter at deep­er lev­els of under­stand­ing we find our­selves awash in a sea of cos­mic music — surg­ing, bil­low­ing, ani­mat­ing. If I were going to look for a metaphor to describe the atom, it would­n’t be a bil­liard ball but a musi­cal leit­mo­tif. And mech­a­nism has come to mean much more than a clock­work or a wind-up toy. The mod­ern con­cept of mech­a­nism is relat­ed to eco­log­i­cal whole­ness: every part of a com­plex sys­tem plays a role in the evo­lu­tion of the whole. To admit that we are mat­ter and mech­a­nism is to ground our selves in the whole­ness of the cos­mos.
Yours,
Chet Ray­mo

Dear Mr. Ray­mo,
OK, OK, but even if I con­cede all of that, what of free­dom and cre­ativ­i­ty?
Sin­cere­ly,
I.M.Curious

Dear I.M.Curious,
Free­dom and cre­ativ­i­ty are abstrac­tions describ­ing com­plex behav­iors. Might it not just be pos­si­ble that sim­i­lar behav­iors will emerge when com­put­er sys­tems reach a cer­tain lev­el of com­plex­i­ty? No present-day com­put­er begins to approach the com­plex­i­ty of the human brain — with 100 bil­lion mas­sive­ly inter­con­nect­ed neu­rons (nerve cells). A recent paper in the jour­nal Nature announced the fab­ri­ca­tion of sil­i­con chips designed to mim­ic the elec­tro­chem­i­cal oper­a­tion of neu­rons. If it were pos­si­ble to pack enough of these sil­i­con cir­cuits togeth­er we would cer­tain­ly have con­struct­ed an arti­fi­cial brain — and per­haps an arti­fi­cial mind. I may be wrong. But proof will be in the pud­ding, not in philo­soph­i­cal argu­ment. Huge­ly com­plex, ultra high-speed com­put­ers, mod­eled on the machin­ery of the human brain, await us in the next cen­tu­ry. Rather than wear our­selves out debat­ing the nature of con­scious­ness, let’s wait and see how these machines illu­mi­nate the ques­tion.
Yours,
Chet Ray­mo

Dear Mr. Ray­mo,
I hope you are wrong. I am rather fond of the idea that con­scious­ness will for­ev­er escape the explain­ers’ grasp.
Sin­cere­ly,
I.M.Curious

Dear Mr. Curi­ous,
So am I. But take a look, for exam­ple, at The Amaz­ing Brain by Robert Orn­stein and Richard F. Thomp­son. The more we learn about the bio­log­i­cal machin­ery of con­scious­ness the more mirac­u­lous it seems. To say that the mind is elec­tro­chem­i­cal does not dimin­ish our con­cept of self; rather, it sug­gests that the cos­mos was charged with the pos­si­bil­i­ty of becom­ing con­scious from the first moment of cre­ation. The new­ly-emerg­ing con­cept of self is mate­ri­al­is­tic and mech­a­nis­tic, but it is also capa­cious enough to embrace the past as well as the future, and expan­sive enough to entan­gle the rest of the uni­verse.
All the best…