Steven Weinberg * k* R/ W* \) p2 }/ h8 C$ e ?7 Q1 U$ S5 |
Steven Weinberg is in the Department of Physics,# }' n& M3 U. A: ?. s& Q! H+ x
the University of Texas at Austin, Texas 78712, 6 q+ a7 }' ?. Z# S$ u0 g# IUSA. This essay is based on a commencement talk " K3 @+ h) {* f2 U D0 }" ugiven by the author at the Science Convocation at# O4 ~; r- k- I" Z" h& c5 G
McGill University in June 2003.) h, M8 S" V7 w: l9 x" N0 t8 M
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When I received my undergraduate degree — about a hundred years3 `* c1 w# U# U/ V' ~
ago — the physics literature seemed to me a vast, unexplored ocean, * K w5 t& p" I* y2 J* V/ h+ l$ Fevery part of which I had to chart before beginning any research of my own. How % i) n# A+ m* G0 K/ c( C9 t' Mcould I do anything without knowing everything that had already been done? 6 K; ?1 Y% q ] \( wFortunately, in my first year of graduate school, I had the good luck to fall into the 4 I. X2 T7 r, _( H& }hands of senior physicists who insisted, over my anxious objections, that I must start- h O. H5 p4 K& w% Y4 ]4 Z! C& l
doing research, and pick up what I needed to know as I went along. It was sink or ; }# n8 W# ~+ b+ Y* d/ ~7 ~swim. To my surprise, I found that thisworks. I managed to get a quick PhD —. i) Z+ K" ~+ I$ ]- n
though when I got it I knew almost nothing about physics. But I did learn one big# J3 Q2 ~4 K- V6 S( c6 E2 i5 }% G
thing: that no one knows everything, and you don’t have to . * ~; {( I9 n) B( H+ G( Z' j1 E8 S4 H
Another lesson to be learned, to continue , A% N! G7 D' G# u& }6 \9 wusing my oceanographic metaphor, is that ( [: i' E# k3 g, f4 ?4 I, g- nwhile you are swimming and not sinking you0 n$ y+ H6 c( K- ?$ U
should aim for rough water. When I was, K6 @7 Q' {2 b8 Q: g
teaching at the Massachusetts Institute of& S: k, s4 k, ]4 B7 y: p
Technology in the late 1960s, a student told # i C: y2 W& ^' h7 E `$ o5 mme that he wanted to go into general, W [! r! A# m. s+ u$ i6 Y
relativity rather than the area I was working $ `6 r f) j" m5 zon, elementary particle physics, because . X' V4 W- G# T1 kthe principles of the former were well0 f2 V2 {2 n t' ^
known, while the latter seemed like a mess 7 R# ?7 _1 K% r# a6 ^! Z Cto him. It struck me that he had just given4 ?: i" l5 V: f8 C: ^& L
a perfectly good reason for doing the opposite. 9 T$ ~; R" d( [- x9 e" c! t0 YParticle physics was an area where& ^9 s- z! w, l$ i& @4 M
creative work could still be done. It really was1 U Q6 u: Y; i z
a mess in the 1960s, but since that time the1 V0 O W+ L0 p8 {& t; P4 b7 v
work of many theoretical and experimental + B; V8 d7 x6 Fphysicists has been able to sort it out, and3 [7 a9 k/ N' d( s9 m
put everything (well, almost everything)# L" k& p, ^" X( ], h3 v
together in a beautiful theory known as$ Z# r( D0 d2 Q5 J+ r3 d5 U# q
the standard model.My advice is to go for the ; o, m4 c5 j0 y0 b$ C4 z( Cmesses — that’s where the action is. * C; J. o8 Y3 r7 D6 C4 E! b! H0 } A7 T1 y# B5 g% V
My third piece of advice is probably the: y: H+ c$ Y2 |9 p* v
hardest to take. It is to forgive yourself for" @* e4 [. }+ X' Q
wasting time. Students are only asked to i# |5 n& A ~- \
solve problems that their professors (unless 0 X3 P0 \1 t9 s* |1 Vunusually cruel) know to be solvable. In. j* q+ i k1 f( l% x B
addition,it doesn’t matter if the problems are+ W4 O% s/ Y9 C* ^. Q& g
scientifically important — they have to be 9 ]6 x/ c1 g* F- p( `solved to pass the course. But in the real 8 w+ |5 z7 j* w! ?! Iworld, it’s very hard to know which problems: M4 Q' [+ h6 W# s2 p4 z
are important, and you never know whether6 H8 M+ `9 v' L, u
at a given moment in history a problem is 5 ?5 h0 I* x8 [solvable. At the beginning of the twentieth2 r. v9 g: o9 |+ n7 ]
century, several leading physicists, including 2 U: Z G7 e8 H4 f2 M5 c3 t1 H6 y6 ALorentz and Abraham, were trying to work2 ]" m( F% Q" `4 U
out a theory of the electron. This was partly/ f% e. S0 q* h4 r+ M2 s
in order to understand why all attempts to. T3 l6 | I5 ]% K, K w
detect effects of Earth’s motion through the$ s5 F' X! t! t; `
ether had failed. We now know that ; k( u) a w) M! l5 C0 dthey were working on the wrong problem.8 w6 k$ Q0 M y! w) Z2 U
At that time, no one could have developed a( t+ A3 m! z5 K1 n& C- [
successful theory of the electron, because- d; j( a1 s" G2 M
quantum mechanics had not yet been ! u/ V$ }9 F [" ydiscovered. It took the genius of Albert6 M/ m3 E |. r5 @% e+ v3 v
Einstein in 1905 to realize that the right * s+ J* P' h- u4 Yproblem on which to work was the effect* ]! `: n/ d. r w" `1 U
of motion on measurements of space and: ] [+ z" ~! c# |' o3 o& F* Y
time. This led him to the special theory of * |% Y: j1 n4 H5 t1 e* ~% ^$ B3 D! l' Mrelativity. As you will never be sure which - U6 q1 I2 Z0 L4 A z# bare the right problems to work on, most2 ? W) U0 o. I3 u
of the time that you spend in the laboratory : E- g: x1 c) D! O, H$ C7 Gor at your desk will be wasted. If you want / {: o$ k5 z. f$ m& D- G: b% k" Mto be creative, then you will have to get used. C% u. G% Q/ D" r6 R2 @( _0 A( _
to spending most of your time not being% m0 x; N% o* ^
creative, to being becalmed on the ocean of' M6 C y$ u) m* c, a
scientific knowledge. 8 ` ?8 u a% S. e5 ^' ^% k/ B $ A+ L7 K9 v, v7 u; LFinally, learn something about the history9 O$ H6 q6 _1 X
of science,or at a minimum the history of your , X$ u) J; p aown branch of science. The least important & B8 z/ J: K, O) Vreason for this is that the history may actually ! f' [& I" ^3 n9 y" e0 r/ r! K+ {; \be of some use to you in your own scientific+ ]/ Q6 r4 G' _
work. For instance, now and then scientists: ?5 X& `) \# g; w& n& R
are hampered by believing one of the oversimplified : y0 ]3 I8 l4 j3 E, l5 emodels of science that have: c# W E3 W( {! k
been proposed by philosophers from Francis* V/ `4 m3 T( o8 ?0 r1 t
Bacon to Thomas Kuhn and Karl Popper. , ]9 }% L$ l7 s' L4 z6 o7 p( j. n; ZThe best antidote to the philosophy of science6 l/ V8 y" h3 _3 e" O/ G
is a knowledge of the history of science. , r" k) @- W; |- SMore importantly, the history of science# x: G& t' \! y
can make your work seem more worthwhile & [ L# r7 r C f7 eto you. As a scientist, you’re probably not7 [6 F* T: ?4 i z
going to get rich. Your friends and relatives. I! V v: Q/ a) e) x# R
probably won’t understand what you’re' Q5 K f, @" c5 ^, a5 p8 a9 G
doing.And if you work in a field like elementary 5 X/ r5 w' N! n$ j5 Hparticle physics, you won’t even have the 9 r( j* l; T0 E, Ysatisfaction of doing something that is : I }) t4 C! k3 Fimmediately useful. But you can get great , F. k8 t W7 I2 N# Nsatisfaction by recognizing that your work in' m: X# q6 J2 m! D3 V. N5 @
science is a part of history.0 l* h4 S+ A# K2 r4 ]
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Look back 100 years, to 1903. How 9 o. H& ]( g7 [1 R2 jimportant is it now who was Prime Minister 3 i/ o: O$ M |8 S4 q7 x. \- Dof Great Britain in 1903, or President of the ! y5 J1 Z# m; y) }United States? What stands out as really % f$ N. f& A0 W$ b1 P+ nimportant is that at McGill University,+ V! C4 D6 F5 M) @* r7 M1 d3 w+ m
Ernest Rutherford and Frederick Soddy were * K, ^( c2 s1 `8 G% h* _1 w- eworking out the nature of radioactivity.$ m, v) }# d1 \( S/ o) p+ c: g
This work (of course!) had practical applications,: `. U$ T/ f* \& H! q4 r c
but much more important were its$ Q1 S/ E( S3 j! ]
cultural implications. The understanding of , D' a. ~: M6 H0 \radioactivity allowed physicists to explain! P! ~' X7 {& C. f6 ]# D2 p, I
how the Sun and Earth’s cores could still be, `' y8 @; s' T! n% Y5 O
hot after millions of years. In this way, it5 x" H* j- l; J$ E2 S3 z
removed the last scientific objection to what! j* F2 m8 C) @8 h/ P
many geologists and paleontologists 1 J7 U! y0 X+ f9 I K7 dthought was the great age of the Earth and : p8 `- A+ x9 ?, jthe Sun.After this,Christians and Jews either1 V0 `1 _- t. b% x
had to give up belief in the literal truth of7 N# X" E# b% l1 G7 X
the Bible or resign themselves to intellectual) K( T. [: S+ @
irrelevance. This was just one step in a . X {' m( Y: U5 o4 L& B- i! Fsequence of steps from Galileo through 7 |; L; ]7 j0 [' ]! iNewton and Darwin to the present that,time6 M: X3 W- [" O; A1 k9 I
after time,has weakened the hold of religious 6 G; L' d& L9 e4 z9 D7 o3 Edogmatism. Reading any newspaper nowadays : J* Z( w. U0 {; _. e) d1 z4 Uis enough to show you that this work - P' k3 k0 ]8 b, ^5 a% Eis not yet complete. But it is civilizing work,8 b# I& e" I: D: Y5 w0 X% F' P
of which scientists are able to feel proud.