We’ll always be stuck in the middle

Originally published 27 March 1995

“You’re search­ing, Joe, for things that don’t exist.”

Joe, of Robert Frost’s poem In the Home Stretch, is search­ing for begin­nings and ends. There are no such things, says the poet. Only middles.

We have been hear­ing a lot late­ly about begin­nings and ends. The begin­ning of the uni­verse. The end of physics.

Some physi­cists talk about a “final the­o­ry,” a “the­o­ry of every­thing,” or GUT (grand uni­fied the­o­ry) that will account in prin­ci­ple for all that exists. This the­o­ry will explain how mat­ter, ener­gy, and the laws of nature emerged with a kind of log­i­cal neces­si­ty in the first moments of creation.

The­o­ret­i­cal physi­cist Stephen Hawk­ing goes as far as to say that in dis­cov­er­ing the final the­o­ry we will under­stand the mind of God.

Some of this talk of an end to physics is polit­i­cal rhetoric (“Give us $10 bil­lion for a new super accel­er­a­tor and we will dis­cov­er the secret of the uni­verse”). Some is the hubris that seems to infect sci­ence at each cen­tu­ry’s end.

In the late 1700s sci­en­tists believed that New­ton­ian mechan­ics was a final the­o­ry of the nat­ur­al world. Then along came elec­tric­i­ty and mag­net­ism to deflate the pre­sump­tion of the mechanists.

A hun­dred years lat­er the great physi­cist William Thomp­son assert­ed that the com­bined laws of mechan­ics and elec­tro­mag­net­ism explained in prin­ci­ple all there was to under­stand. Only two clouds lurked on the hori­zon, he said: the neg­a­tive result of the Michel­son-Mor­ley exper­i­ment and the unex­plained char­ac­ter of so-called black body radi­a­tion.

It turned out that these two “clouds” held the seeds of the rel­a­tiv­i­ty and quan­tum revolutions.

Now we are again being told that the end of physics is just around the cor­ner. The recent dis­cov­ery of the top quark, a long-sought fun­da­men­tal par­ti­cle that tops off a pre­dict­ed ros­ter of quarks, fuels the physi­cist’s sense of completion.

All that remains to be found, they say, is the Hig­gs boson, a super-mas­sive par­ti­cle (called the “God par­ti­cle” by Nobel lau­re­ate Leon Led­er­man) that orches­trat­ed the Big Bang. Find­ing the Hig­gs will take us to the begin­ning of time and the end of physics.

Per­mit me to demur. The end of physics is not nigh. The begin­ning is not with­in our grasp, nor the end. We are not in the home stretch.

We are crea­tures of the mid­dle. We have learned more about the world than it might have been rea­son­able to expect, but we have much, much more to learn.

Let me play the prophet. I pre­dict that we are again on the brink of a rev­o­lu­tion in knowl­edge that will unfold dur­ing the first decades of the next cen­tu­ry. It will not be insti­gat­ed by high-ener­gy physi­cists or cos­mol­o­gists, but by the­o­rists of life and mind.

The new rev­o­lu­tion will not car­ry us deep­er into the sub-quark realm of mat­ter or clos­er to the Big Bang; it will reveal itself rather clos­er to home, in stud­ies of bio­chem­i­cal com­plex­i­ty. It will not be based upon high-ener­gy accel­er­at­ing machines and tele­scopes, but upon ever small­er, ever cheap­er, mas­sive­ly par­al­lel-pro­cess­ing computers.

It seems to me that the two great­est rid­dles fac­ing sci­ence today are these: How does a fer­til­ized egg direct itself to become an ele­phant, a mouse, or a gnat? And how does the human brain store and process information?

I believe that find­ing the answers to these rid­dles will involve a com­plete­ly new way of con­cep­tu­al­iz­ing the world, as rad­i­cal as the rev­o­lu­tions insti­gat­ed by New­ton and Einstein.

I wish I were smart enough to guess what this new physics will be. I sus­pect it will be more syn­thet­ic than reduc­tion­is­tic, empha­siz­ing sys­tems rather than ele­ments. It will lend itself to rep­re­sen­ta­tion in com­put­ers and to visu­al display.

The new physics will be no less math­e­mat­i­cal and quan­ti­ta­tive than the physics we have today. Obser­va­tions of nature will con­tin­ue to be impor­tant, of course, but exper­i­ments in the real world will more often than not be replaced by com­put­er simulations.

A hun­dred years from now we will look back and won­der how we ever dreamed in 1995 that we were close to a final the­o­ry. And we may once again have the hubris to believe that a final the­o­ry is just around the corner.

If so, we will not have learned our les­son: We are finite crea­tures play­ing on a shore of infi­nite mys­tery, draw­ing pret­ty rep­re­sen­ta­tions in the sand.

It would be fool­ish to deny that each rev­o­lu­tion in knowl­edge brings us clos­er to the truth. But there is no begin­ning or end of knowing.

Only a middle.

---

The Hig­gs boson was dis­cov­ered in 2012. The final The­o­ry of Every­thing, long sought by physi­cists, remains elu­sive to this day. ‑Ed.