Steven Weinberg 0 V. K7 [4 j0 x$ Q+ w& M- d6 E* V$ l; K
Steven Weinberg is in the Department of Physics,) U6 g4 q X) o! Z
the University of Texas at Austin, Texas 78712,6 s1 o7 a2 C) E# ~& f
USA. This essay is based on a commencement talk ) X7 Q* X0 R& x5 b- Y6 vgiven by the author at the Science Convocation at 1 q- h O: X7 l9 r% |# GMcGill University in June 2003. $ C( y' F1 |; q6 h" a- Q 9 p& W& ?) W5 C- S3 z7 n0 u# d! OWhen I received my undergraduate degree — about a hundred years ~! I, p" i: ?: l) a2 M. @1 {6 rago — the physics literature seemed to me a vast, unexplored ocean,/ [* R) M$ t) \
every part of which I had to chart before beginning any research of my own. How 9 }" Z/ W; j% N4 rcould I do anything without knowing everything that had already been done?1 p( l1 z x# r% P, E/ ~
Fortunately, in my first year of graduate school, I had the good luck to fall into the " Y' _* \$ I" c4 v- phands of senior physicists who insisted, over my anxious objections, that I must start5 \* v# K* I2 T# W0 L
doing research, and pick up what I needed to know as I went along. It was sink or + x9 y1 ? u/ fswim. To my surprise, I found that thisworks. I managed to get a quick PhD — . n, x) y; Q; j7 ]3 Sthough when I got it I knew almost nothing about physics. But I did learn one big1 C7 ]7 F- u$ [' e9 o
thing: that no one knows everything, and you don’t have to . ! ] [, C- {% }3 R m w* I/ T/ o: v, R! c8 ^
Another lesson to be learned, to continue ! c$ f' y4 I3 p4 Z; cusing my oceanographic metaphor, is that 3 v* x5 ]/ ~1 i7 U% k* n2 qwhile you are swimming and not sinking you # i l3 s, b- Z* x Gshould aim for rough water. When I was9 _9 B, H5 v% F1 g" a" \ K. g
teaching at the Massachusetts Institute of 4 c( a, K2 V7 L' [; QTechnology in the late 1960s, a student told 7 X/ y8 O" U$ m* F" s0 zme that he wanted to go into general# P3 c5 W, N! ?' o+ ]: A% G
relativity rather than the area I was working ! i6 P/ l5 y3 n kon, elementary particle physics, because4 K: C. p3 A C/ m8 D. w
the principles of the former were well 5 X% x) s9 I' }known, while the latter seemed like a mess 7 f. y; b8 n5 N2 k# Jto him. It struck me that he had just given 8 s' [. W- E$ B8 W1 ~a perfectly good reason for doing the opposite.4 |( }# M, y+ I
Particle physics was an area where 4 W! X8 O+ S" b5 Q" T2 Ccreative work could still be done. It really was 2 A, G" M7 g' I/ Y- {, ^0 r8 ca mess in the 1960s, but since that time the. T6 ^$ r/ N/ b* D6 ?0 o
work of many theoretical and experimental, \% y! [1 b8 b* Y
physicists has been able to sort it out, and! M( v% p: ]7 I
put everything (well, almost everything)' X/ a) J4 z! K2 a
together in a beautiful theory known as ( a+ p0 W5 ]# C# L5 m# X; D9 f1 Athe standard model.My advice is to go for the" F5 g- W+ C# l" C& r" s5 d. f- M
messes — that’s where the action is. + \ \" W' _3 v3 d6 D8 T 3 b$ |2 K- R3 {" r; F& tMy third piece of advice is probably the# D( M2 U9 b: B$ y! x9 n; r$ P' {
hardest to take. It is to forgive yourself for 6 [/ Y+ d c* g1 L1 Y& q# g0 Rwasting time. Students are only asked to 1 O* M. p+ t! U6 ?- nsolve problems that their professors (unless 3 ?/ m; t4 _& ^; ?% y4 m# Bunusually cruel) know to be solvable. In 8 p+ S" B2 a7 F7 p. P: raddition,it doesn’t matter if the problems are 6 Z9 P9 m L* b+ R& J, s* k" Escientifically important — they have to be* e; Z6 [4 I& e
solved to pass the course. But in the real $ A _1 J3 U: w w# |" F. I% oworld, it’s very hard to know which problems7 Y: O) q, j+ E# F
are important, and you never know whether % v7 y% v2 ?6 V$ M5 d( i, \: S4 oat a given moment in history a problem is ! Q3 d! q8 E# n7 msolvable. At the beginning of the twentieth5 V+ u7 J4 u' c
century, several leading physicists, including; V; Z% W, u; }6 w L
Lorentz and Abraham, were trying to work( {: ]8 ?2 Q, ]+ t' d. W
out a theory of the electron. This was partly$ S/ ] W/ M; q, P1 }8 G
in order to understand why all attempts to + a5 D, Y: G, ?/ x1 I% fdetect effects of Earth’s motion through the 9 f8 t0 r4 B7 i: O/ }0 k6 ^% pether had failed. We now know that # M2 |4 |/ b* E6 x0 |# u" F' D- b1 F6 gthey were working on the wrong problem. 9 ]0 t- e+ l/ QAt that time, no one could have developed a 4 J$ |; f4 O& q' C# x( wsuccessful theory of the electron, because & z" _3 b* m7 V2 U7 H# M! O- n8 D8 i* Gquantum mechanics had not yet been $ b) M% e+ c8 @* Z6 c9 [ a: k" ]discovered. It took the genius of Albert+ h+ v) Q5 y" n7 i
Einstein in 1905 to realize that the right ) g( j* A$ P& Vproblem on which to work was the effect / `& F+ x) ^3 n7 b9 ^" M8 T+ }of motion on measurements of space and ' ~; r5 b) H$ E0 `# Ztime. This led him to the special theory of ! X: L4 c+ Y2 j$ l& k" N$ N4 J& Qrelativity. As you will never be sure which 2 G3 u$ C) s' Z! ~+ Aare the right problems to work on, most& @9 S) U1 `* m% i$ g8 G: V
of the time that you spend in the laboratory) C# R- }/ W2 C
or at your desk will be wasted. If you want! V4 f% k0 p" s* N4 n
to be creative, then you will have to get used& u8 c* b1 _# @% p
to spending most of your time not being : O6 G; y$ V# v, \* mcreative, to being becalmed on the ocean of/ `* X9 t5 v! y) ?# v! Y6 q! K
scientific knowledge. 1 O+ r) ]& G4 l* M4 p+ @0 d5 r; |! y
Finally, learn something about the history ) ]% n5 X6 s% t8 @; g% Rof science,or at a minimum the history of your, v7 o9 i6 i: K6 r1 K
own branch of science. The least important5 ]& H: O: M9 B, E% Q
reason for this is that the history may actually: z9 _$ |3 U1 U$ A( o, W/ X: s
be of some use to you in your own scientific" K. s5 i; B; Y% \% `/ w
work. For instance, now and then scientists : O3 a. b2 |/ p7 Kare hampered by believing one of the oversimplified 7 E6 q! C& z0 Q- omodels of science that have/ S' H5 ^" `5 [
been proposed by philosophers from Francis . V3 b! P1 B/ W' y: Y( QBacon to Thomas Kuhn and Karl Popper. 0 c: |' f2 H: e4 F3 G/ d. F. mThe best antidote to the philosophy of science+ ?$ u% [& f% v) B7 G$ L
is a knowledge of the history of science. - J) F4 \; r( V2 H( p- N2 g0 Q# S' sMore importantly, the history of science ( K. p. P) x7 L4 ican make your work seem more worthwhile- \! E' ], T" Y7 f$ T. Y/ G3 M
to you. As a scientist, you’re probably not ) j# O/ U; M- u- T A$ Z8 Wgoing to get rich. Your friends and relatives l0 O. C: i& ^0 Q4 s2 L% v* U5 k
probably won’t understand what you’re 4 R: D0 o% E- J6 l( B( h: h( F4 ]doing.And if you work in a field like elementary # T. V W; z8 \/ @% \; H6 ~2 Pparticle physics, you won’t even have the & U+ ^9 n# R! S. v& p" n; z* ^5 N. [satisfaction of doing something that is + |) e6 o& M- F% Y: E2 F. I0 Eimmediately useful. But you can get great ' |" o1 B0 W( |4 l9 q0 d" _satisfaction by recognizing that your work in1 W5 p; A+ l8 o" k
science is a part of history.' J# T5 G* D. t# q' }$ J
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Look back 100 years, to 1903. How3 \; [! X5 a% X( T/ [. x
important is it now who was Prime Minister 9 e4 o3 {' C: _# l, F2 yof Great Britain in 1903, or President of the 4 ?" r+ ?( n$ ?) X+ u9 w4 pUnited States? What stands out as really ! ^) Y& I" p7 Mimportant is that at McGill University, 8 [2 I+ y" E& ]' M/ ~& D9 p, qErnest Rutherford and Frederick Soddy were % Q# ]" p, |% [+ {5 o5 bworking out the nature of radioactivity.. L5 l6 `/ P4 x+ y% h
This work (of course!) had practical applications, - ^+ W! B' j, rbut much more important were its : F) M, ^' {, `8 t7 J! ocultural implications. The understanding of y* u- F @, ~radioactivity allowed physicists to explain/ W! J D2 ^# `) [3 F; o
how the Sun and Earth’s cores could still be ! r& n# N5 P+ I9 b9 m7 ?hot after millions of years. In this way, it ; [1 a' R+ g8 wremoved the last scientific objection to what9 ]8 |$ L9 g% `7 |) @8 C/ i
many geologists and paleontologists; C. m6 \3 R* X4 ^
thought was the great age of the Earth and' b' O B4 k2 x+ w9 Z$ q* ?
the Sun.After this,Christians and Jews either" B6 `+ P. l2 c. ]! b; T8 t+ |% S h
had to give up belief in the literal truth of& E/ D* I0 \+ b9 n
the Bible or resign themselves to intellectual; c/ p# R+ Y! k
irrelevance. This was just one step in a! e7 |5 c; |* v. W' k! ~, m8 t
sequence of steps from Galileo through2 \* |5 v' _+ \2 }* Q1 `
Newton and Darwin to the present that,time & G/ Y0 T p! a) v9 u9 [after time,has weakened the hold of religious 1 u* o G- i4 {) i6 B( bdogmatism. Reading any newspaper nowadays9 E# x) y" ^2 A5 y% i
is enough to show you that this work* N& e# Y5 V( R8 Q
is not yet complete. But it is civilizing work,9 h8 s! r, _6 M5 i J
of which scientists are able to feel proud.