Steven Weinberg/ A6 l' n6 i$ k2 P! p0 P; N5 k- ?
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Steven Weinberg is in the Department of Physics, 5 c( x( q% j: Z4 S/ Rthe University of Texas at Austin, Texas 78712, u) {$ s) C5 X' s: Q
USA. This essay is based on a commencement talk ; h9 {, R1 J9 O( R+ o6 W3 x5 Pgiven by the author at the Science Convocation at, L5 H9 k8 {( `! o6 n$ o
McGill University in June 2003.& o) P+ {/ L* d
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When I received my undergraduate degree — about a hundred years , Y. p0 u( C) N: Bago — the physics literature seemed to me a vast, unexplored ocean, 9 J! C$ ^2 R) m, ^1 yevery part of which I had to chart before beginning any research of my own. How & t1 z. y$ t9 c6 Dcould I do anything without knowing everything that had already been done?+ B: J- p' y& s* Q
Fortunately, in my first year of graduate school, I had the good luck to fall into the, k% ^& K! Z' a5 X3 D
hands of senior physicists who insisted, over my anxious objections, that I must start- V. p3 J" n2 x. Z
doing research, and pick up what I needed to know as I went along. It was sink or0 S c S) s) i( s* e
swim. To my surprise, I found that thisworks. I managed to get a quick PhD — 4 i5 L h8 i0 F3 q9 l# C4 cthough when I got it I knew almost nothing about physics. But I did learn one big ' O1 u, k P& E. v* g7 `thing: that no one knows everything, and you don’t have to . / d& K/ ^/ n: a! t1 m. A& q3 ^3 Q 9 e" C. q! }9 @1 Y8 y3 ?- MAnother lesson to be learned, to continue6 V9 Z9 j @* @8 ]
using my oceanographic metaphor, is that * z& \- H; T# L5 s! p1 Z/ h& owhile you are swimming and not sinking you ' i l. w$ U8 ~- ]$ `( C, |should aim for rough water. When I was 7 M7 T# I# j4 ]1 ?; e4 cteaching at the Massachusetts Institute of! R |' c) `0 o: u+ G8 B5 T8 m
Technology in the late 1960s, a student told ( I" M1 r+ b5 U9 ~+ a' M& D4 j( n! Lme that he wanted to go into general 7 A$ _8 Q9 Z) Prelativity rather than the area I was working8 K$ q" a# ?, v& N8 i1 K1 ?
on, elementary particle physics, because & b+ W8 y) E' F) ^the principles of the former were well# J/ f0 _( `, x1 i4 f) L
known, while the latter seemed like a mess / m( ~% x7 V6 U t# s; y' @1 C) Mto him. It struck me that he had just given4 j1 d" H* W9 q( D' d6 F3 f+ R/ D
a perfectly good reason for doing the opposite.4 q; q5 i1 I, j' c
Particle physics was an area where " V w: K Z- G1 |+ C9 v3 Z# zcreative work could still be done. It really was / O& S+ U- Y6 {a mess in the 1960s, but since that time the6 `, {2 Q6 k2 h3 c
work of many theoretical and experimental( n% m7 [, ^1 F
physicists has been able to sort it out, and 8 d) m4 s" e3 S- {# Iput everything (well, almost everything) ) q; p: N# e% J8 \3 ttogether in a beautiful theory known as. N% z' @, t1 q1 h5 l
the standard model.My advice is to go for the ) c% F- ~0 `1 O2 F0 u ~0 J% Hmesses — that’s where the action is." \; }" Z( q) d3 m+ W+ p
2 C$ P4 l+ {/ B+ ?My third piece of advice is probably the' N4 @9 w" G) D, h7 `7 K
hardest to take. It is to forgive yourself for + Q: q, Z8 B: Z* o1 O) D& Lwasting time. Students are only asked to # [6 [1 V$ W+ B( ~3 d" \# _8 t8 Dsolve problems that their professors (unless ; O8 F+ g: ^3 [7 s5 Wunusually cruel) know to be solvable. In' A$ n: ?2 U# i& x* l
addition,it doesn’t matter if the problems are 2 s* @5 ^1 e- Q9 D5 m' x4 Y; V0 dscientifically important — they have to be $ ~$ m7 X4 c; O, n3 msolved to pass the course. But in the real & M& Y& Z8 x T& Aworld, it’s very hard to know which problems - P6 N; K" Z# M9 w8 Qare important, and you never know whether ) Z& M) n2 M2 iat a given moment in history a problem is/ M" u4 a. X9 B1 D! d8 @7 L) H
solvable. At the beginning of the twentieth / j: o; n; q: `0 G& |century, several leading physicists, including5 x4 i6 }! X8 F
Lorentz and Abraham, were trying to work + U( Y0 N u/ I3 d: `3 Z; g) Mout a theory of the electron. This was partly# T4 E" A( n; U3 m! ?
in order to understand why all attempts to 9 z. j" y' o2 ~' ~detect effects of Earth’s motion through the4 c) b- Q: Z7 `; p
ether had failed. We now know that& N8 B$ H6 Z% X+ b) y% M% f" h
they were working on the wrong problem. R9 S- y! H; w9 ]2 N/ c" `At that time, no one could have developed a* b# Z; g. h) \1 u5 A4 g: H% h+ J
successful theory of the electron, because$ j& r: E- y1 U" g2 D. h1 B# C
quantum mechanics had not yet been( O. r! X% c* i0 g
discovered. It took the genius of Albert . _ G6 s t6 f. J, e: NEinstein in 1905 to realize that the right) v7 o- v* T% n# Z
problem on which to work was the effect" p. v& C2 X* W
of motion on measurements of space and% z; u# [+ c7 D+ Q W
time. This led him to the special theory of & A+ Z2 u: f, g9 s& S( C% I# s- Vrelativity. As you will never be sure which9 d9 S( L" ~! `9 L: A
are the right problems to work on, most 8 ~ g, v d" H, [- w# Cof the time that you spend in the laboratory! |* o8 A! H8 Q; u
or at your desk will be wasted. If you want+ D8 p5 t1 G( g3 F7 H- L9 r, C" V# g
to be creative, then you will have to get used5 C' }+ v% y6 d1 r; `( {
to spending most of your time not being, a' ~0 t9 ?0 g2 q$ m
creative, to being becalmed on the ocean of V7 H( n0 c" k. \, U( ]scientific knowledge. 2 Z5 b' z* i( H; @7 D" D0 q ?1 h: c6 a* F6 \ M
Finally, learn something about the history 9 v3 t3 \" y6 l! zof science,or at a minimum the history of your - L% i' @' k% P: ?/ T- Mown branch of science. The least important ( w% x9 Q: f/ p' X; K: M/ oreason for this is that the history may actually' p4 E% c- |9 Y: O
be of some use to you in your own scientific . C, r% N9 @1 U2 E3 E5 ^work. For instance, now and then scientists, R! \' R3 r* n1 Z
are hampered by believing one of the oversimplified , p) p" f- Y; ?. I9 Ymodels of science that have ! c# ?+ j7 k- B; ?been proposed by philosophers from Francis! Q0 z3 h9 ?: G2 a+ R W6 ?
Bacon to Thomas Kuhn and Karl Popper. ' r8 Q3 C: i3 i% \. n3 ]9 pThe best antidote to the philosophy of science q( e+ t4 J5 U$ `6 H/ ]% r$ g& Uis a knowledge of the history of science. w1 }; a8 F: t7 O* _: j
More importantly, the history of science 4 b/ S/ B% t; Lcan make your work seem more worthwhile 2 ?+ ~6 O, S! V1 q% `+ `to you. As a scientist, you’re probably not 1 S" {% A- k A) i& `- {1 S% vgoing to get rich. Your friends and relatives 2 B" W+ x; C3 E oprobably won’t understand what you’re! s q( K2 L: [& ?
doing.And if you work in a field like elementary : g& a8 c7 V' }6 Y* R0 ?0 dparticle physics, you won’t even have the 9 P0 Q) |; w& g7 R l. B+ \: P: osatisfaction of doing something that is- h6 }& |7 |8 ~) s, }
immediately useful. But you can get great p+ L4 r- q Psatisfaction by recognizing that your work in " [* n# T* i+ o$ Vscience is a part of history./ y* G; Q4 P% F; {
1 J$ P8 A0 p9 z$ u9 gLook back 100 years, to 1903. How! W9 h0 j8 u5 H3 t
important is it now who was Prime Minister ( H! \9 M5 u, x- ?) Jof Great Britain in 1903, or President of the! U5 k+ U1 O( l; A: h9 |
United States? What stands out as really 1 P/ V$ B% J$ q5 |important is that at McGill University,* F4 _+ F9 m# r0 r
Ernest Rutherford and Frederick Soddy were4 P$ d) e: G0 x
working out the nature of radioactivity. ' ]! u$ p) X8 j* w X+ aThis work (of course!) had practical applications,2 z( n3 V& W$ u% C! y. r L O9 r# D
but much more important were its ) d q* ^9 p5 _* O0 V; y# hcultural implications. The understanding of/ R. U$ c* V/ D6 @/ R( o9 _7 t# m0 |
radioactivity allowed physicists to explain , i% r4 R: k/ a* U. \9 Fhow the Sun and Earth’s cores could still be , k6 h- s/ \ ?hot after millions of years. In this way, it / D! N, }% ?9 t: Z }+ Xremoved the last scientific objection to what7 |2 ^/ {5 Y" r: D& ~" S
many geologists and paleontologists1 X% s' s5 p" s6 g% W# J
thought was the great age of the Earth and% V9 E$ v" _6 ~% ]
the Sun.After this,Christians and Jews either 9 M* n7 L% B8 b( v& S# H6 ]had to give up belief in the literal truth of B7 h6 s+ e! j: F% n5 \2 H- Vthe Bible or resign themselves to intellectual5 I# R8 W. n9 b1 s1 y( v* g
irrelevance. This was just one step in a % w4 @; a8 ?! \9 [" \. g8 G8 I) Y/ [; Gsequence of steps from Galileo through 6 Z, q$ ~# h$ k/ Q. U8 ^Newton and Darwin to the present that,time3 E4 ~# e5 n1 O( _9 O& G$ i
after time,has weakened the hold of religious v8 M, m6 C/ y$ x8 xdogmatism. Reading any newspaper nowadays9 T/ w& {6 ? M4 Q8 p
is enough to show you that this work, l" h8 L7 o$ t8 v
is not yet complete. But it is civilizing work, 6 q+ b: h4 y3 Q: u6 c/ _' N9 lof which scientists are able to feel proud.