Steven Weinberg 4 r: Z( |$ j" x9 C; W! J# i$ x$ F3 F
Steven Weinberg is in the Department of Physics, ! E" R. i4 ]+ z# }the University of Texas at Austin, Texas 78712, + G& A* m: P: B& T$ n; K- LUSA. This essay is based on a commencement talk4 t+ ^0 F6 K* q2 y2 U# s
given by the author at the Science Convocation at + T3 l# W5 z$ I7 { @$ kMcGill University in June 2003. 5 k* }% S' s& K5 U' P1 k* E1 `6 I7 y# ` ^/ F
When I received my undergraduate degree — about a hundred years8 U& z9 A# y; E- f$ C0 |9 o
ago — the physics literature seemed to me a vast, unexplored ocean,8 M' E9 L$ S% @! U
every part of which I had to chart before beginning any research of my own. How* V( ?" @0 ^1 J% C' V
could I do anything without knowing everything that had already been done?8 @0 p; d1 [* O; P
Fortunately, in my first year of graduate school, I had the good luck to fall into the) r) I! \& a3 ?9 q5 W" o& @
hands of senior physicists who insisted, over my anxious objections, that I must start ! R- w. }' Y) K$ v7 g2 n4 S1 ^doing research, and pick up what I needed to know as I went along. It was sink or / `2 m8 `; i* Hswim. To my surprise, I found that thisworks. I managed to get a quick PhD —+ D' ~2 r! {6 h# B, w8 e& b& T
though when I got it I knew almost nothing about physics. But I did learn one big . u6 V0 z8 V0 c8 j$ Z) y! o6 {thing: that no one knows everything, and you don’t have to ./ r' |* s/ S1 _3 x& W
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Another lesson to be learned, to continue ! q$ r- o7 N0 \9 E) S! t8 _using my oceanographic metaphor, is that/ F. o# {+ y) L6 S
while you are swimming and not sinking you 9 z) |2 v. |& P1 w. x6 g3 C2 i# mshould aim for rough water. When I was : h1 M y( Y s0 T) tteaching at the Massachusetts Institute of! i' ^- [: W: f: E
Technology in the late 1960s, a student told 9 d7 D1 Q, K# q) U' s4 Q7 X! lme that he wanted to go into general8 G# t0 g: K, x/ J2 V
relativity rather than the area I was working ' g0 N6 P4 d, ?# C3 Gon, elementary particle physics, because 9 ?* Y1 i+ X3 x `the principles of the former were well; Q2 `2 ]) c( q- q3 t8 j! H
known, while the latter seemed like a mess 3 a# s# i$ B; {( J" n3 bto him. It struck me that he had just given % v6 n4 a1 z& C) ja perfectly good reason for doing the opposite.- r* f8 z9 S6 d' r
Particle physics was an area where" ], G9 P v4 k! L! V- Y
creative work could still be done. It really was 4 _ U5 @' h1 N( O) o& q# }6 fa mess in the 1960s, but since that time the# ~3 w( F$ P% I0 [1 h7 [& p
work of many theoretical and experimental . P) r9 C* o4 Zphysicists has been able to sort it out, and! i7 N; ~& I3 R5 ]/ _+ { V
put everything (well, almost everything)3 y9 H- ~0 f! A
together in a beautiful theory known as' k# |7 K0 I$ M/ Y1 {
the standard model.My advice is to go for the 4 O% V) `/ e& E9 m& \! j* }messes — that’s where the action is.# R: k: O3 G* i. E+ N. C0 g
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My third piece of advice is probably the0 L7 H8 p" \; G" K9 j
hardest to take. It is to forgive yourself for/ v% ~9 Z' C4 y
wasting time. Students are only asked to \! s: f: `3 a( `3 k) x! m
solve problems that their professors (unless ' y n7 J& E$ a2 @$ h) U5 Munusually cruel) know to be solvable. In$ U K* z; L* x# D; k8 ^' s
addition,it doesn’t matter if the problems are5 l/ d/ D! o2 G
scientifically important — they have to be) R6 z/ A( v* U3 L/ y
solved to pass the course. But in the real9 y+ |: q. y# T8 r+ {
world, it’s very hard to know which problems 8 H4 `, L6 ~& ~8 P1 N4 v8 Hare important, and you never know whether I0 {2 C3 C/ F! _" Lat a given moment in history a problem is6 A% l9 Z/ }4 H. R/ V
solvable. At the beginning of the twentieth ! d1 i5 w6 z+ v7 Acentury, several leading physicists, including - f) R- I- F$ O0 m ?" y0 }Lorentz and Abraham, were trying to work ( B4 B4 _- @- H% e7 mout a theory of the electron. This was partly6 p7 W' u; o3 _& t# b' l) o
in order to understand why all attempts to1 T* {/ K1 R# m, P
detect effects of Earth’s motion through the : I! k ~& w$ d G. _! Yether had failed. We now know that& e* e" h! h$ i9 Y* p1 Z7 p9 c3 y
they were working on the wrong problem. . A3 Z( K: H+ d0 a) ^+ r6 gAt that time, no one could have developed a& _3 E& g9 f0 c7 P: H
successful theory of the electron, because+ C1 x9 g, |( Z5 R6 W3 c* z
quantum mechanics had not yet been 9 [3 v. b& V2 j. u$ gdiscovered. It took the genius of Albert 1 @/ t0 C2 z2 I p0 j( `Einstein in 1905 to realize that the right' _. J/ `4 y/ o' S2 Q5 ^
problem on which to work was the effect# n* _( [6 o# X8 }
of motion on measurements of space and9 V5 U& u8 u1 k8 o
time. This led him to the special theory of 1 h# R6 Y% X) ~+ O) x) Orelativity. As you will never be sure which # q$ f+ }/ C8 Z% J7 v. G& aare the right problems to work on, most# t! ^& ~5 L8 G- ?5 V$ F/ a
of the time that you spend in the laboratory 6 ~. v7 a: Y$ [, d) \ j1 bor at your desk will be wasted. If you want$ F$ n. c4 a' g7 E. z4 g/ ]
to be creative, then you will have to get used + |( p( @6 j& R, G, {2 u1 x- Jto spending most of your time not being 4 j5 @) l5 w: V d9 z/ Ecreative, to being becalmed on the ocean of+ l" m+ _: A; v/ X
scientific knowledge. . E" R/ y* ^9 _. `" T8 v9 t7 h7 M
Finally, learn something about the history $ f1 C2 |, j8 s' ]/ Tof science,or at a minimum the history of your 5 t. H8 h. _) V9 }own branch of science. The least important, U3 n7 F8 R3 D. C5 N
reason for this is that the history may actually) [1 x- J S9 y: }
be of some use to you in your own scientific 9 M6 Z6 S4 L \/ Z1 t. `work. For instance, now and then scientists" i8 R* k- M0 d$ G4 Y% {
are hampered by believing one of the oversimplified 5 N- l: C& N, ^/ |$ o) pmodels of science that have - Y: [$ H; c* S; ~* R1 k: Nbeen proposed by philosophers from Francis . X8 y" r0 @, J% NBacon to Thomas Kuhn and Karl Popper.+ Q& {) p9 F& m& f
The best antidote to the philosophy of science& v$ G: H( ?: Z |4 W% b" O2 _
is a knowledge of the history of science. % R( i# V' C- V7 F2 v: PMore importantly, the history of science4 i; n" ?; G, z5 Z4 C& E* h7 W: p& y, g
can make your work seem more worthwhile ! m* R% F: U) J, _% ato you. As a scientist, you’re probably not & c( ]5 S/ e, ^' }9 m6 egoing to get rich. Your friends and relatives " x8 }% h D6 k; s# Kprobably won’t understand what you’re$ H) O7 x9 ?) L2 R$ U
doing.And if you work in a field like elementary 7 f8 P N& w+ p( gparticle physics, you won’t even have the% O$ ^# J" m5 M% ~" `
satisfaction of doing something that is / u8 d6 J [6 t. d; r! H8 }immediately useful. But you can get great ! t4 [- T) L7 h6 asatisfaction by recognizing that your work in2 {: O% G9 z; b& k
science is a part of history.( D1 m$ ]5 b: \8 K9 ?
: P. B. }; E5 E/ u+ [Look back 100 years, to 1903. How 5 M7 X% E' M7 m9 }7 f% e1 Y( himportant is it now who was Prime Minister ( C/ N. Z2 k: k; O3 Y: T# U. mof Great Britain in 1903, or President of the $ d$ d( A) G1 _& n; h& QUnited States? What stands out as really 4 D$ `7 s$ L \% f! f1 e1 h" Fimportant is that at McGill University,5 o2 L1 L5 X8 p: Z L$ i9 x, `- _
Ernest Rutherford and Frederick Soddy were. \. i1 _0 X. H
working out the nature of radioactivity. " J- {$ k: F# H; c: E% QThis work (of course!) had practical applications,' K8 m* l4 u/ m5 F; d; N( P" x7 k1 S
but much more important were its / R/ E; G' u4 d6 F: Zcultural implications. The understanding of7 H% ]$ x0 ?5 b. q
radioactivity allowed physicists to explain 5 C; Q* u- k$ F+ C. o5 Ihow the Sun and Earth’s cores could still be1 R+ D0 n$ Y. q
hot after millions of years. In this way, it9 @2 M# v- b( P. }1 X" |
removed the last scientific objection to what4 _) a* N' K5 o% f- K( Q+ i
many geologists and paleontologists+ P1 t% e/ P% Y3 P F0 a
thought was the great age of the Earth and ) ?# O& O$ ]) s: a9 j" B; othe Sun.After this,Christians and Jews either * l4 x4 b" W# c0 n# \- ~3 ~( Xhad to give up belief in the literal truth of/ ^- _9 L" ] }, \/ c6 Y0 T2 F" G
the Bible or resign themselves to intellectual ; W9 U% {( W1 P) G* _1 k6 dirrelevance. This was just one step in a5 l* r2 c# e6 a D* {1 o D1 F+ v
sequence of steps from Galileo through ( ] ?8 _' @% ?8 CNewton and Darwin to the present that,time 0 Q6 T3 H9 I% B# L$ g1 _/ Nafter time,has weakened the hold of religious8 H2 ^7 N" k, \3 m& I' V ]: @
dogmatism. Reading any newspaper nowadays4 L/ m. t0 f2 _" u
is enough to show you that this work 8 Z7 _/ I$ y/ F: `) T* Sis not yet complete. But it is civilizing work, % Y) g0 M# p+ _9 yof which scientists are able to feel proud.