No One Knows What Science Doesn’t Know

At a fam­ily party some years ago, one of my un­cles re­marked on how lit­tle sci­ence re­ally knows. For ex­am­ple, we still have no idea how grav­ity works—why things fall down.

“Ac­tu­ally, we do know how grav­ity works,” I said. (My father, a Ph.D. physi­cist, was also pre­sent; but he wasn’t even touch­ing this one.)

“We do?” said my un­cle.

“Yes,” I said, “Grav­ity is the cur­va­ture of space­time.” At this point I had still swal­lowed Feyn­man’s line about be­ing able to ex­plain physics to one’s grand­mother, so I con­tinued: “You could say that the Earth goes around the Sun in a straight line. Imag­ine a graph that shows both space and time, so that a straight line shows steady move­ment and a curved line shows ac­cel­er­a­tion. Then curve the graph pa­per it­self. When you try to draw a straight line on the curved pa­per, you’ll get what looks like ac­cel­er­a­tion—”

I never heard about any­thing like that,” said my un­cle.

When was the last time, in his­tory, when it was pos­si­ble for a sin­gle hu­man to know the knowl­edge of the most ad­vanced civ­i­liza­tion? I’ve seen var­i­ous es­ti­mates for this—usu­ally in the form of poly­maths nom­i­nated for the po­si­tion of “last per­son to know ev­ery­thing”. One plau­si­ble can­di­date is Leonardo da Vinci, who died in 1519 - shortly af­ter the print­ing press be­gan to be­come pop­u­lar, and shortly be­fore Coper­ni­cus inau­gu­rated the sci­en­tific rev­olu­tion.

In the an­ces­tral en­vi­ron­ment it was pos­si­ble to know ev­ery­thing, and nearly ev­ery­one did. In hunter-gath­erer bands of less than 200 peo­ple, with no writ­ten liter­a­ture, all back­ground knowl­edge was uni­ver­sal knowl­edge. If one per­son, in a world con­tain­ing 200 peo­ple to­tal, dis­cov­ered how grav­ity worked, you could cer­tainly ex­pect to hear about it.

In a world of 6 billion peo­ple, there is not one per­son al­ive who can say with cer­tainty that sci­ence does not know a thing. There is too much sci­ence. Our cur­rent life­times are too short to learn more than a tiny frac­tion of it, and more is be­ing pro­duced all the time.

Even if last week’s tech­ni­cal jour­nal doesn’t con­tain the an­swer to a mys­tery, that doesn’t mean that no one knows it. Maybe some­one out there is typ­ing up the pa­per at this very mo­ment. You can’t gen­er­al­ize over all 6 billion peo­ple in the world be­cause you haven’t talked to all of them—which is a non-an­ces­tral con­di­tion! For the vast ma­jor­ity of hu­man­ity’s evolu­tion­ary his­tory, it was pos­si­ble to meet ev­ery­one in your lit­tle world. Now there’s 6 billion peo­ple who might know the an­swer to any ques­tion you care to ask, and you can’t ask all of them.

No one knows any­more what no one knows.

My un­cle is not an iso­lated phe­nomenon. I’ve met peo­ple who think that sci­ence knows noth­ing about the brain, that thought is a com­plete mys­tery unto us. (My fa­vorite was the fel­low who con­fi­dently as­serted that neu­ro­science had been un­able to as­sign any func­tion “to the cere­bral cor­tex”.) As Tom McCabe put it: “Any­one who claims that the brain is a to­tal mys­tery should be slapped up­side the head with the MIT En­cy­clo­pe­dia of the Cog­ni­tive Sciences. All one thou­sand ninety-six pages of it.”

I haven’t seen the movie What The Bleep Do We Know, but if the hor­ror sto­ries are true, it’s one long cel­e­bra­tion of imag­i­nary ig­no­rance. Par­tic­u­larly the “mys­te­ri­ous effect of con­scious ob­ser­va­tion” in quan­tum physics, which was ex­plained away as or­di­nary de­co­her­ence in the 1950s, but let’s not get into that again.

Ig­no­rance should not be cel­e­brated in the first place; I’ve made this point be­fore. It is a cor­rup­tion of cu­ri­os­ity to pre­fer the ques­tion to its an­swer. Yet peo­ple seem to get a tremen­dous emo­tional kick out of not know­ing some­thing. Worse, they think that the mys­te­ri­ous­ness of a mys­te­ri­ous phe­nom­ena in­di­cates a spe­cial qual­ity of the phe­nomenon it­self, in­fer­ring that it is surely differ­ent-in-kind from phe­nom­ena la­beled “un­der­stood”. If we are ig­no­rant about a phe­nomenon, that is a fact about our state of mind, not a fact about the phe­nomenon it­self.

In the an­ces­tral en­vi­ron­ment, there was a cer­tain per­ma­nence to the di­vi­sion be­tween ig­no­rance and knowl­edge. If none of your fel­low hunter-gath­er­ers knew what made rain fall, it was likely that no one would ever find out in your grand­chil­dren’s life­times. To­day, the ab­sence of knowl­edge is a frag­ile and tem­po­rary con­di­tion, like the dark­ness in a closet whose door hap­pens to be shut. A sin­gle thought can shat­ter the ab­sence of thought. Every sci­en­tific dis­cov­ery ever made, de­stroyed an an­cient ab­sence-of-knowl­edge dat­ing back to the dawn of time. No one knows what 6 billion peo­ple don’t know to­day, and still less does any­one know what 7 billion peo­ple will know to­mor­row.