Steven Weinberg 9 z' @$ Z1 X6 T8 O8 E0 C' ^$ N ) i+ R, V6 |9 A: U/ W# F& _* lSteven Weinberg is in the Department of Physics, $ u) X! s; f$ X- D8 [2 hthe University of Texas at Austin, Texas 78712, ( S) S0 y% Q6 c; ?) HUSA. This essay is based on a commencement talk ( C8 n6 S% l# i& I# Fgiven by the author at the Science Convocation at( H4 f+ y' z( K% D2 U. ?
McGill University in June 2003. ; j; f8 o. {" B* c+ @. k* @+ H& Z$ E8 A
When I received my undergraduate degree — about a hundred years' @& p" I- @: F/ q
ago — the physics literature seemed to me a vast, unexplored ocean, , J; m; l' v9 cevery part of which I had to chart before beginning any research of my own. How 5 ^3 |* V! C9 K% Kcould I do anything without knowing everything that had already been done? ; c& J" d$ j. a6 I$ sFortunately, in my first year of graduate school, I had the good luck to fall into the ! g# t" ?9 M( _7 D7 L) Fhands of senior physicists who insisted, over my anxious objections, that I must start / z9 j( |' d& a0 A# L* U4 g7 J [doing research, and pick up what I needed to know as I went along. It was sink or8 |3 ^7 m3 n2 I) p
swim. To my surprise, I found that thisworks. I managed to get a quick PhD — 4 L7 M# ]/ @7 K U& z$ Rthough when I got it I knew almost nothing about physics. But I did learn one big 5 c1 P' |- c* d- c/ w, Athing: that no one knows everything, and you don’t have to . " E( J. Z0 T( m 8 V* c! V* X/ q* f: D9 ^Another lesson to be learned, to continue( Q: g8 l* H$ e$ Y
using my oceanographic metaphor, is that + w+ w2 J( @" M; F1 W, a# n3 Lwhile you are swimming and not sinking you+ W9 s) @% f" t" Z/ _9 L( @
should aim for rough water. When I was 9 @1 v* w6 ]4 M! `$ U( c( U. S& lteaching at the Massachusetts Institute of ; j* T& B; {$ s% l% z* mTechnology in the late 1960s, a student told2 }# T7 J' {+ a
me that he wanted to go into general ( G' Y# t- o7 f3 qrelativity rather than the area I was working9 L% k. H w9 o: Q: g( i3 g
on, elementary particle physics, because $ j* ^- q; C7 M$ z. n3 W" G$ I7 Vthe principles of the former were well: H) M9 k" i+ m& _" {
known, while the latter seemed like a mess ( D8 F3 d% c/ |3 }& j) Sto him. It struck me that he had just given ) ]' o0 a9 P3 _# v- G Da perfectly good reason for doing the opposite. ; Y- W7 H2 t! W% Y" D- b5 ]. r3 p9 d2 VParticle physics was an area where 2 Y' b3 L5 K# icreative work could still be done. It really was: ^9 D, x- `7 q
a mess in the 1960s, but since that time the " R8 w8 ]; w) t0 U+ Z0 f( lwork of many theoretical and experimental9 {+ J3 ?# G* F4 O0 [
physicists has been able to sort it out, and ) U y; P3 p+ W4 ?8 }: d1 X6 }2 Dput everything (well, almost everything)3 D+ N8 u1 z6 g: l& U4 s! v" a% f
together in a beautiful theory known as" B- W D( L- @' M
the standard model.My advice is to go for the: w& z ?6 ]6 P- j/ V
messes — that’s where the action is. 7 _; y D( d( y ; Q2 h+ \% }5 jMy third piece of advice is probably the ! S$ r' }6 q, Ihardest to take. It is to forgive yourself for+ U; K0 u7 q% ?+ E5 B) D
wasting time. Students are only asked to . u# A0 Y: `5 [solve problems that their professors (unless ; [+ }. c& X9 P/ gunusually cruel) know to be solvable. In 9 j/ C; [3 z2 R6 W% S( u1 oaddition,it doesn’t matter if the problems are 4 f5 E' s, C' u7 wscientifically important — they have to be8 h2 F( c3 y. s" N5 i
solved to pass the course. But in the real - P8 W' o4 l9 [7 G9 J: ~3 B! tworld, it’s very hard to know which problems 0 v! M7 ^5 P4 R @- D* ~are important, and you never know whether. f3 ~2 d1 o8 p: y8 ?
at a given moment in history a problem is 8 Q# f9 x, t' rsolvable. At the beginning of the twentieth @% w g/ A/ icentury, several leading physicists, including3 Z/ T$ F: [5 d `! C' o
Lorentz and Abraham, were trying to work ! m" i4 @* A' U ?/ y/ Lout a theory of the electron. This was partly8 |7 F3 ]: ]+ G: r
in order to understand why all attempts to6 {* N* e; r& n& ?6 h7 |
detect effects of Earth’s motion through the7 v" L0 r1 r7 ~6 J$ [9 Q
ether had failed. We now know that* s! M: c# T: i6 a- D. v8 O
they were working on the wrong problem.: U" j( x" I( k5 l3 l/ F
At that time, no one could have developed a. Y% {# f* B: F$ m# S/ J
successful theory of the electron, because 6 W7 v7 ~* I) F' F/ Gquantum mechanics had not yet been ) s1 O7 _6 t' Y$ Z+ ?* `) h5 m" adiscovered. It took the genius of Albert 8 `4 i8 p1 b$ V" EEinstein in 1905 to realize that the right" e I6 p7 L3 \2 V& f9 @- ~) G7 V
problem on which to work was the effect+ o* f4 I5 @. { C1 s* a
of motion on measurements of space and% u6 e! Q: _- E: y% X; z6 P
time. This led him to the special theory of * ]- ]: D9 b0 O2 |relativity. As you will never be sure which - j1 o' V. Z6 X5 I4 N+ iare the right problems to work on, most 9 K0 z: {) Y0 N. z+ l8 v M+ }8 vof the time that you spend in the laboratory 2 V6 t6 r S8 }- n6 b' sor at your desk will be wasted. If you want, L1 s) p+ o, @5 S. E. Z8 h
to be creative, then you will have to get used, X9 w$ ^8 c' W0 \! u5 s+ N
to spending most of your time not being0 l4 t# m4 j0 @* i
creative, to being becalmed on the ocean of 7 _! ~- M* E' Q! lscientific knowledge. " i4 ^0 L% v( N Q$ Q 4 s- l1 I3 w. w9 x7 m+ p* y6 UFinally, learn something about the history 7 R! f* |6 O5 Y, K7 ^of science,or at a minimum the history of your9 W( C5 a. y. W# t: \
own branch of science. The least important$ n$ z) g) F9 z: K' E& X
reason for this is that the history may actually 6 h: S, w( |% r. a) T( b( ]; b" abe of some use to you in your own scientific * T+ g+ N, O2 v1 Wwork. For instance, now and then scientists / F) I! i. s1 ] R* H: E5 a) lare hampered by believing one of the oversimplified ' n! K2 q5 x9 Q& rmodels of science that have7 j/ e: K* I2 t/ D) K+ w* I. l
been proposed by philosophers from Francis 8 M8 ?. x c! f6 IBacon to Thomas Kuhn and Karl Popper. 4 D7 [% a% M- G3 fThe best antidote to the philosophy of science 4 z# p/ ^' I" k5 j: [2 `is a knowledge of the history of science. 2 g$ Z* Y4 u! r/ n4 X' _) PMore importantly, the history of science- w* q6 t8 A) |4 A! d+ v
can make your work seem more worthwhile- b5 \% z0 I! r( \/ f/ b
to you. As a scientist, you’re probably not 2 ^$ p% t) g9 C7 Agoing to get rich. Your friends and relatives. U: W2 [4 e" m( _" W% l! E
probably won’t understand what you’re) ]. O& z1 ]4 T9 K0 ~5 X7 O6 n
doing.And if you work in a field like elementary& T1 y _0 D; O ?
particle physics, you won’t even have the4 Z) |) O/ z; N% e
satisfaction of doing something that is 9 E7 E. U( }1 b# Z* m! himmediately useful. But you can get great 3 h9 H& o; m4 z- G0 Rsatisfaction by recognizing that your work in - H/ ~) Z3 l0 i: ^+ v9 |science is a part of history. # {. F) q7 z8 ~$ s ' P" ^" K1 b0 V7 `- K2 `Look back 100 years, to 1903. How + q6 [) g- q: v. ^7 ]3 |# cimportant is it now who was Prime Minister 5 }9 Y- o0 x- U7 A, o$ x/ Zof Great Britain in 1903, or President of the ' G! D% I- ^. X8 ^6 _0 B4 X1 |5 fUnited States? What stands out as really 3 f4 c8 j$ V5 Z7 Gimportant is that at McGill University,4 T! ?& d8 d7 H4 E* u2 G( d5 K" i
Ernest Rutherford and Frederick Soddy were( F# P' {2 k/ L: N a0 w
working out the nature of radioactivity. : ?- w: M9 t- a C3 G$ y( J+ \This work (of course!) had practical applications, p! d( o3 d& X6 t m/ f; Q" Jbut much more important were its7 Z8 l- d7 E% h$ |
cultural implications. The understanding of # w+ p) ~' i; Y5 iradioactivity allowed physicists to explain6 E; n# G$ ]/ n8 x" G: L* P {
how the Sun and Earth’s cores could still be: j: ?. {3 T; g& K0 T+ D8 [
hot after millions of years. In this way, it0 K. c3 _$ S' R
removed the last scientific objection to what1 o- }' S: U- p( E
many geologists and paleontologists - |) ^! W$ s$ O _% M# |' othought was the great age of the Earth and 0 H9 M& @! v9 R+ p* `( P, L' vthe Sun.After this,Christians and Jews either : y1 m; m0 b2 u0 q. \had to give up belief in the literal truth of , x, w6 ]( z* o5 O( lthe Bible or resign themselves to intellectual q q* T4 i' Y' q# s9 Virrelevance. This was just one step in a ' s1 G! T* p$ Y/ o' Z1 k% M7 esequence of steps from Galileo through $ ?" p1 Y' d+ O3 ]% a" V# O" g* n7 pNewton and Darwin to the present that,time 0 C$ s8 F' L e5 y; {after time,has weakened the hold of religious& m$ O9 d0 v+ }
dogmatism. Reading any newspaper nowadays% V5 y$ Q7 X* t/ d6 y
is enough to show you that this work' a6 E3 p# y# t6 C; M; u
is not yet complete. But it is civilizing work,6 [ ?$ A2 A4 T& y" u1 p8 f
of which scientists are able to feel proud.