Steven Weinberg% S, a9 L, K8 v) i* X
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Steven Weinberg is in the Department of Physics, ' G8 K: c$ w# ^& Tthe University of Texas at Austin, Texas 78712,& w& Z2 e4 o( U. }6 X2 x$ P8 u
USA. This essay is based on a commencement talk ( \1 X) w# c* h# qgiven by the author at the Science Convocation at - T \( O" g* A& z# ?( @& H( dMcGill University in June 2003. 3 Y/ S! Z/ h. X* t1 T3 i2 A. F( @' Y' e0 c9 \
When I received my undergraduate degree — about a hundred years* N: D+ o) w. E7 V# t
ago — the physics literature seemed to me a vast, unexplored ocean, * Q C6 k( A) M- b L+ [9 D/ |7 pevery part of which I had to chart before beginning any research of my own. How / ~5 e& N* ]6 r, G* q0 l. @could I do anything without knowing everything that had already been done? # X9 A3 i# y* N5 |5 t. ]% r) BFortunately, in my first year of graduate school, I had the good luck to fall into the7 d$ ], o$ h/ U9 U& W! j0 r# b: Z
hands of senior physicists who insisted, over my anxious objections, that I must start# r/ h7 G, A3 L' E& L; B' h L
doing research, and pick up what I needed to know as I went along. It was sink or( [1 x; Y' a6 M2 r2 m: U( r
swim. To my surprise, I found that thisworks. I managed to get a quick PhD —2 z/ T% H7 _" r6 b0 X
though when I got it I knew almost nothing about physics. But I did learn one big0 y. q1 N% f* ` z9 h5 l" d
thing: that no one knows everything, and you don’t have to ., ]1 P1 V: w. w( z" h
/ P, n6 \6 X1 F' q2 t
Another lesson to be learned, to continue , M6 J# k. u5 D5 n5 V' tusing my oceanographic metaphor, is that - Q& ` Q# _: h- [while you are swimming and not sinking you) s9 q# y" [1 s x. W
should aim for rough water. When I was 3 p' x; _. V$ R$ Q, t( }9 Tteaching at the Massachusetts Institute of! ?1 |' t1 C% G' ^) U2 ]
Technology in the late 1960s, a student told5 L7 U1 u1 T% y1 a! P) c5 y2 k
me that he wanted to go into general/ b9 H% z3 w9 ^- \% {3 U
relativity rather than the area I was working ; `8 u' N5 }0 Y- f0 A9 M6 a. zon, elementary particle physics, because # a; s9 e; j) g4 {" ]' }1 Rthe principles of the former were well7 @ b S+ w4 d* {$ W
known, while the latter seemed like a mess 7 |% ?* J2 i l& L2 t0 W, }to him. It struck me that he had just given + G# S7 ?! z9 [4 F- P5 ca perfectly good reason for doing the opposite.; R* `5 p0 Z5 B" k1 L
Particle physics was an area where# y! i( A5 u' v4 c
creative work could still be done. It really was V5 r, j) D: r: L6 _: o8 a
a mess in the 1960s, but since that time the 8 c0 c" I# V$ x! n* A8 m" f' [1 Rwork of many theoretical and experimental9 R3 a, t/ E1 j8 R+ e7 b# p3 q( u
physicists has been able to sort it out, and# Z9 o& S. i; S/ T1 ^+ u
put everything (well, almost everything)8 i% F9 G0 B/ A
together in a beautiful theory known as ! x) ]- I! o# k" Fthe standard model.My advice is to go for the ! \9 u- ? V" f5 Qmesses — that’s where the action is. 4 c4 ]5 _ z& u+ {( {. M- Y- m+ k. A8 W- T, x7 Q- f
My third piece of advice is probably the; N% Y3 b# X" W w9 L
hardest to take. It is to forgive yourself for* P, H8 t6 i! Z" c4 S
wasting time. Students are only asked to. o4 x; }% _- \/ b& q/ f
solve problems that their professors (unless* u" o4 _# t$ y/ h& u# X. y
unusually cruel) know to be solvable. In/ k% K! a& Y' m: d
addition,it doesn’t matter if the problems are- g* t5 p7 `4 @1 v$ c
scientifically important — they have to be* P8 I9 S7 N& }0 o7 Y8 T' o, r
solved to pass the course. But in the real ' u L9 g8 s" x; ^world, it’s very hard to know which problems, Y( U6 q/ B% }9 C# }/ |9 m
are important, and you never know whether; }9 f8 g/ ]/ b/ Y/ s" _" ?9 ~
at a given moment in history a problem is ) C% b9 l. X/ Y( esolvable. At the beginning of the twentieth0 `; I, g3 j6 ~' L3 _
century, several leading physicists, including 3 i( N- a" G+ S! cLorentz and Abraham, were trying to work ; ?0 `* d9 D; l# O% }& g( uout a theory of the electron. This was partly ; \7 b# }2 y7 Ain order to understand why all attempts to 0 S0 ?" U9 { X; x0 q- M' O cdetect effects of Earth’s motion through the ' H, S) _9 ]- x7 h3 ^ether had failed. We now know that) d7 Q( \5 A& x
they were working on the wrong problem.! ?8 i4 I5 f9 P; D
At that time, no one could have developed a2 e4 M$ o4 T3 p. S# {9 L
successful theory of the electron, because : h+ C8 D1 M+ b# q: x: Q6 T! Q0 {quantum mechanics had not yet been 2 R) g0 r' V, K! K) Tdiscovered. It took the genius of Albert ' [/ l$ _7 ~; r6 p9 W/ `0 xEinstein in 1905 to realize that the right+ o7 w z. U: M
problem on which to work was the effect# a' O' B* I. E; Y
of motion on measurements of space and. e4 E J' R- g: Y. A
time. This led him to the special theory of # k* N* j0 x$ grelativity. As you will never be sure which. J7 a* A* Q/ ~: g' Q* l* G, b' w
are the right problems to work on, most 4 Q+ ^8 ^" D; g! Nof the time that you spend in the laboratory / y0 `& {- K8 K- Ior at your desk will be wasted. If you want + s/ \1 J5 ~! O: ]4 lto be creative, then you will have to get used - k* a. k; d" B: B3 I* X3 d( X0 m% Ato spending most of your time not being _; g; l+ i% p% I
creative, to being becalmed on the ocean of& ^ V0 w* ?5 P0 s$ f% Z
scientific knowledge. 1 [" H0 h. ]6 A' l0 S3 T% `1 Y) T6 z; u8 X
Finally, learn something about the history 4 n5 ` |1 s+ b7 Xof science,or at a minimum the history of your + q! a+ P# Q2 R& y" w$ l3 A( S4 Town branch of science. The least important % Q" G6 a' E* o" i, \/ _4 Zreason for this is that the history may actually : c+ Z' Q" g5 ]) G" Hbe of some use to you in your own scientific E8 {! t' m. J9 V5 j0 \
work. For instance, now and then scientists & }/ `2 R. T3 U* x9 l# t% nare hampered by believing one of the oversimplified! `7 w- n }7 P& f2 p
models of science that have4 N% A' T; d! x3 `0 p
been proposed by philosophers from Francis 7 U: J, U5 a2 D Z1 vBacon to Thomas Kuhn and Karl Popper. ) }# A* m6 a- [0 PThe best antidote to the philosophy of science % v" C4 ]* z2 \is a knowledge of the history of science.2 g) U8 B) Z4 L6 n7 ^ Y
More importantly, the history of science & U# `9 O8 o: m% E. H& \can make your work seem more worthwhile 7 E' L' H: e( v! I* oto you. As a scientist, you’re probably not! b( g, ]. s& s: J
going to get rich. Your friends and relatives4 x1 h( e' C* c$ Q: Z u
probably won’t understand what you’re+ z& J4 z- O$ N
doing.And if you work in a field like elementary/ I( E) _& F! t
particle physics, you won’t even have the 6 o, Z& z8 V! |4 }5 ~1 e; ?satisfaction of doing something that is : B6 R) n U8 `* N) W9 \7 U- ?3 Cimmediately useful. But you can get great 2 F$ L3 P h/ T5 [: Q5 \6 U0 Z, Csatisfaction by recognizing that your work in % J2 ^' k7 a0 a0 W- J5 Yscience is a part of history.( N" I5 B! l" l4 F* m' q7 x
- a) Y* N: D( a0 \! d2 z, xLook back 100 years, to 1903. How ( Q$ z7 o* d! A. ~* w$ Limportant is it now who was Prime Minister $ U2 A7 G5 O; R: yof Great Britain in 1903, or President of the0 L) B2 k: r, `1 N( {) m
United States? What stands out as really ?7 i0 ] |* g7 \# i! e( t0 qimportant is that at McGill University, ( l a8 R8 m+ wErnest Rutherford and Frederick Soddy were 5 K8 E. q$ C4 z- nworking out the nature of radioactivity., M- m: T" O5 I- J+ a. [1 A
This work (of course!) had practical applications, 6 w- @9 b$ l: J, l9 j' F; F4 ^+ ~but much more important were its/ c4 ], j/ n( u; x2 q' g
cultural implications. The understanding of ) j% I! i6 s. h8 |radioactivity allowed physicists to explain8 {1 A2 U" j+ V( q% ?9 J% C
how the Sun and Earth’s cores could still be & C1 j6 P( O; m9 q- lhot after millions of years. In this way, it. R1 i7 j" x! y+ @+ F
removed the last scientific objection to what + L6 |+ I1 i( d! t$ m& C+ k1 Z/ Fmany geologists and paleontologists : y T3 X# H V# hthought was the great age of the Earth and: U" n. V3 C' @9 A! t. O- T
the Sun.After this,Christians and Jews either. R( n5 i; i) ^+ B
had to give up belief in the literal truth of7 t* Z0 u/ k* k% s2 }$ ?
the Bible or resign themselves to intellectual3 P& v+ J V, [$ [) l
irrelevance. This was just one step in a* y( U5 _' d: x5 |3 C
sequence of steps from Galileo through: `3 g7 H( ^% G/ K# h8 S
Newton and Darwin to the present that,time 9 C( f/ c- |' Q _after time,has weakened the hold of religious" ?1 {" a7 A5 m1 J9 d0 D) s
dogmatism. Reading any newspaper nowadays ( d" i) y% V9 }5 N, X" W0 kis enough to show you that this work5 m* \6 u7 k w0 P/ g5 \
is not yet complete. But it is civilizing work,& q. W% C$ p# l
of which scientists are able to feel proud.