Steven Weinberg c& s; L7 L3 Z. |2 Q) D& C9 O
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Steven Weinberg is in the Department of Physics, 1 V$ d' @) t6 d' ithe University of Texas at Austin, Texas 78712,! j/ t( ?. a: R: A
USA. This essay is based on a commencement talk$ ^- u1 ^- q1 @1 ?7 j# O
given by the author at the Science Convocation at; T! M1 h2 }6 r& R6 ~8 Q
McGill University in June 2003. ' V$ D& u0 g9 Q# d: F 2 e* S9 l; k! m8 \: Q" V u: _8 RWhen I received my undergraduate degree — about a hundred years ! T6 Q5 c3 n3 ^ y5 N. A. z/ {ago — the physics literature seemed to me a vast, unexplored ocean, , `' |3 G/ I# Qevery part of which I had to chart before beginning any research of my own. How . w, ~- I. K% Ucould I do anything without knowing everything that had already been done?0 s: i' V$ x4 t. K0 l8 ]7 {3 ]5 {$ k
Fortunately, in my first year of graduate school, I had the good luck to fall into the' {( Z% e) b3 T! f% Q
hands of senior physicists who insisted, over my anxious objections, that I must start & f2 I) I$ ~$ ldoing research, and pick up what I needed to know as I went along. It was sink or ! [( o9 L/ F5 r" u( _swim. To my surprise, I found that thisworks. I managed to get a quick PhD — & S* o1 I# v! X% ethough when I got it I knew almost nothing about physics. But I did learn one big . l; v6 o- J2 I0 k2 \7 k# d1 _7 Sthing: that no one knows everything, and you don’t have to . # H. _+ e: U) _ ! g% J5 f8 L* B* H- B2 rAnother lesson to be learned, to continue# l) K; j9 M8 g- p0 b) ]2 b
using my oceanographic metaphor, is that G( d" i$ [2 h5 z8 U! h- [
while you are swimming and not sinking you 7 l3 z9 ^ m9 ~7 {8 C% X5 Qshould aim for rough water. When I was% @5 q5 M% ?1 @9 z; [
teaching at the Massachusetts Institute of8 u, `- ?9 q3 t
Technology in the late 1960s, a student told \- s- }) B2 l/ Q3 A5 Kme that he wanted to go into general 9 q& x C2 \9 p' _# Qrelativity rather than the area I was working / m3 v, X! e3 F+ f- Pon, elementary particle physics, because 1 x2 J2 ]& `# V$ e" Athe principles of the former were well . X! D- E D7 rknown, while the latter seemed like a mess % {% Z& l0 x/ v' t `- pto him. It struck me that he had just given & L1 K- E. s7 `# O% G. ~! ?a perfectly good reason for doing the opposite.- v- Z$ {+ V; O. ^1 z3 y% u+ Z, M
Particle physics was an area where % u2 p) a' y* @3 [( P$ Bcreative work could still be done. It really was/ M2 i- ?* F# ? r
a mess in the 1960s, but since that time the ' [% G% s" h- ?( x8 ?$ \3 V8 Vwork of many theoretical and experimental3 @" R6 b7 o' k: a/ E3 [2 Q
physicists has been able to sort it out, and 0 \9 ]& E' \3 w' @9 e, cput everything (well, almost everything) & N+ O/ n! y2 G3 w& Gtogether in a beautiful theory known as - g5 p1 x7 r. Q, {% R; Tthe standard model.My advice is to go for the9 q$ _( ?' I3 X7 P
messes — that’s where the action is.6 [ v- E( w0 E1 ~$ l- T! J+ t
+ a" ` I4 I* L; |$ ]My third piece of advice is probably the! E+ I, a& Z* m; Y" k; O
hardest to take. It is to forgive yourself for3 S5 U+ S/ ^- }2 Y& P, z
wasting time. Students are only asked to# B& D; P; c- X$ m4 Y2 T' c& V
solve problems that their professors (unless ' z. f5 a2 |! `0 `) X) Lunusually cruel) know to be solvable. In! P- ]: u' w: W2 d
addition,it doesn’t matter if the problems are) [) Z9 c6 I" P7 l- k9 }
scientifically important — they have to be! e( B) j7 N* u) n
solved to pass the course. But in the real " d* D# G# s1 c% K/ Z5 u, ~1 N% v7 a) ~8 eworld, it’s very hard to know which problems- Z. G* i$ q0 f
are important, and you never know whether 3 T+ w/ {1 z, C) a/ ~" f1 O# R# j. [at a given moment in history a problem is$ e8 H$ y9 k/ M% o: u3 z2 x
solvable. At the beginning of the twentieth; @/ \! d9 x" X4 }. w
century, several leading physicists, including% z' m; V8 G5 A5 \# o% `) u
Lorentz and Abraham, were trying to work. B8 v% T1 u5 I" p! o2 V
out a theory of the electron. This was partly1 ?$ t; j% R1 e! s& ]1 X& `9 ~2 Z5 l
in order to understand why all attempts to . E4 u5 A m2 Ydetect effects of Earth’s motion through the - _, m- |7 r$ W, U& F! Qether had failed. We now know that6 r. U, g9 i: d. G2 z" s: D
they were working on the wrong problem.3 n& O$ M% K$ C: H
At that time, no one could have developed a3 E# o0 P* h- b' Q
successful theory of the electron, because# u! X; p( t. ~1 J! d# v: a
quantum mechanics had not yet been & p# r& g) D l* |# A' Bdiscovered. It took the genius of Albert+ ~5 ~9 F4 g) N* z
Einstein in 1905 to realize that the right/ M- F( z3 j+ j
problem on which to work was the effect ; \- [2 T2 a: e( sof motion on measurements of space and- {' s: m7 f/ U0 y0 @, z5 l
time. This led him to the special theory of 1 b/ Y, ?( b; J: B, M. Q; Erelativity. As you will never be sure which ; P. f9 j7 o7 [; w Jare the right problems to work on, most) G0 r$ A- D" {1 P( Q+ A
of the time that you spend in the laboratory 9 I7 ^/ @. ^( a0 |# [or at your desk will be wasted. If you want4 v/ B( j& b- J4 o# E
to be creative, then you will have to get used3 q4 g9 o- f0 M! b7 i! h) F8 D
to spending most of your time not being * D9 H8 [( Z) ucreative, to being becalmed on the ocean of! V+ Q' Q; g/ b* b9 {. S" j: X' u
scientific knowledge.4 Z h! y7 X" h8 |7 V. u: x
/ _& ^+ ?6 e; E* B9 MFinally, learn something about the history* @$ w% M/ {6 |9 S
of science,or at a minimum the history of your+ P, p7 J0 n6 K
own branch of science. The least important C1 O4 {6 t3 w. I( _* o6 {reason for this is that the history may actually E) M. G6 |+ F2 L# C
be of some use to you in your own scientific 8 r' u7 |. D! I: {# U; g. zwork. For instance, now and then scientists 3 T' ^/ l1 a' J4 a; q: O: l6 _. B2 w' Oare hampered by believing one of the oversimplified - G) _; g6 V* T( }7 }" omodels of science that have ! _. f& i `/ R: F: b9 K0 e3 c7 |% ]3 Gbeen proposed by philosophers from Francis& p& R4 n! n. y! _- b, Y4 u+ B
Bacon to Thomas Kuhn and Karl Popper. 7 }8 E2 o" O/ P# ^The best antidote to the philosophy of science+ p5 j4 \4 l8 `( g5 n
is a knowledge of the history of science.& K) o8 u2 O0 D. t9 f* u
More importantly, the history of science; c f. X$ e1 E( ]5 v. L( S
can make your work seem more worthwhile 2 _- [4 Y# o( F) zto you. As a scientist, you’re probably not 7 J5 q9 I j8 K, U1 Cgoing to get rich. Your friends and relatives ( ~. s2 }- |" R/ q0 C/ `' i, Z; \probably won’t understand what you’re# ^/ `) `( @0 A( s$ y( q- b
doing.And if you work in a field like elementary 4 B: C( t" H$ r6 mparticle physics, you won’t even have the 8 ^5 N0 s' I% c+ `; K4 ?5 c# Isatisfaction of doing something that is / B" z: N* q/ R( i4 ]4 U2 himmediately useful. But you can get great + y7 K% g6 g( u S1 r7 g/ nsatisfaction by recognizing that your work in 3 g+ L' q+ J3 J: `5 ?science is a part of history. $ M; d+ B5 V2 }5 A7 C2 z9 v2 @0 d7 f2 F6 m! `! B! u
Look back 100 years, to 1903. How ! R4 j; f! Q# L& ~; Yimportant is it now who was Prime Minister ) n* s4 Z+ s" C3 ?) Eof Great Britain in 1903, or President of the 3 H; |) a1 _0 E; xUnited States? What stands out as really" U# I1 x5 ~- K; g# u
important is that at McGill University, ~7 d7 s5 d6 K, B$ g+ aErnest Rutherford and Frederick Soddy were. C2 }7 h! ^: F
working out the nature of radioactivity." J9 {: m X; f
This work (of course!) had practical applications, g) l# _$ e Z% s( n4 o9 @1 {7 y( K9 ^
but much more important were its ) w+ d; @- }+ m( _8 Gcultural implications. The understanding of" i* p `, |8 o7 A4 ~9 G* c* z
radioactivity allowed physicists to explain 5 f' E* ^( ]5 A! J: Xhow the Sun and Earth’s cores could still be9 A% l- X% u4 F/ x* @+ V
hot after millions of years. In this way, it @0 [" U/ p* i6 Oremoved the last scientific objection to what ) u g" T% B% qmany geologists and paleontologists - w1 P3 U+ u' z& I! ythought was the great age of the Earth and ' Z' P7 E5 N6 _4 @3 A$ ?the Sun.After this,Christians and Jews either( B0 N0 |2 r& W1 x1 |
had to give up belief in the literal truth of 9 I. X) I$ o( h( |4 @( h# @the Bible or resign themselves to intellectual ' O/ c- s! M9 ?% Mirrelevance. This was just one step in a3 Y9 E$ l& P$ u. ?2 s
sequence of steps from Galileo through 4 w- {4 r( @# m0 HNewton and Darwin to the present that,time/ e' M$ s( k! I% s
after time,has weakened the hold of religious; F! i% c, E% W8 T
dogmatism. Reading any newspaper nowadays5 Y) O9 t) E a0 e2 _
is enough to show you that this work N4 A+ v4 u$ H0 B
is not yet complete. But it is civilizing work, ; K F6 R& c( Oof which scientists are able to feel proud.