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Steven Weinberg
( E9 K) r5 u# p7 P% [1 {! T9 @# P
) f) b: _# Y0 j. dSteven Weinberg is in the Department of Physics,/ T# Y) b: I: U5 u3 J
the University of Texas at Austin, Texas 78712,2 a5 E* c a% D7 B. {5 [" T. f
USA. This essay is based on a commencement talk
( C# S. m# Z, w2 y- Ggiven by the author at the Science Convocation at8 o& R1 k1 p# s$ h! ~
McGill University in June 2003.# K& ^2 `* R1 z/ ?6 t! s
3 p1 U' |& _" e8 i" x% s
When I received my undergraduate degree — about a hundred years& d% C, p6 Q4 C0 I2 W$ Q: {$ g" p
ago — the physics literature seemed to me a vast, unexplored ocean, f+ `7 u5 V6 n( `
every part of which I had to chart before beginning any research of my own. How9 z% Z) m3 E; P' M5 P
could I do anything without knowing everything that had already been done?2 J7 E, { Y0 z( p9 s4 k
Fortunately, in my first year of graduate school, I had the good luck to fall into the5 k: G% ]" w% R5 j9 F. v4 L2 ~
hands of senior physicists who insisted, over my anxious objections, that I must start
. i) k5 ~9 B% L% \8 I" Sdoing research, and pick up what I needed to know as I went along. It was sink or4 w9 `2 E. J w6 J- l* r& C
swim. To my surprise, I found that thisworks. I managed to get a quick PhD —+ r8 R$ h. f, R. [" ?0 H/ t6 u
though when I got it I knew almost nothing about physics. But I did learn one big- K7 S' k/ B* `) e" [
thing: that no one knows everything, and you don’t have to .* o0 ~9 t& b# N1 f- k9 B
! h! P' L0 i/ z% w9 b, DAnother lesson to be learned, to continue
5 l9 Q# {. G( W- b" qusing my oceanographic metaphor, is that& w/ o. l) P0 ?3 P% H$ v( C
while you are swimming and not sinking you3 W# N$ S" }" t, ]5 ^
should aim for rough water. When I was; b1 @, ]: l3 K6 r/ h
teaching at the Massachusetts Institute of3 p6 T# {; p4 E# s# p
Technology in the late 1960s, a student told; _. r/ Z# A8 R; C+ y
me that he wanted to go into general
. e5 r' \; I3 Hrelativity rather than the area I was working; ~. Z$ ?0 ~9 M' D1 k! [# |$ T
on, elementary particle physics, because# x8 O( A' t9 s
the principles of the former were well
/ U) ~* z% j! W( L: tknown, while the latter seemed like a mess
3 L& G: ~" s J9 @to him. It struck me that he had just given
! l% D# ~5 i. M$ N: c8 _, [' Ga perfectly good reason for doing the opposite.
o" ^- ]7 |# ?) V7 pParticle physics was an area where
2 J) Y: `8 R8 C; S1 ]7 J ?creative work could still be done. It really was% D8 I# A, e4 f W, l J
a mess in the 1960s, but since that time the
2 S" F. F( Y- T7 R" V" zwork of many theoretical and experimental3 x" _. z1 |" k- h( Z
physicists has been able to sort it out, and" F7 i4 e& b8 b% T' O
put everything (well, almost everything)* ^6 s1 R z) [ ~/ n: D
together in a beautiful theory known as
) h7 `; R5 L* n7 r, y) [$ k; nthe standard model.My advice is to go for the
! |* N7 y Z9 N% P+ t$ C8 e+ ]* Smesses — that’s where the action is.
, _8 R( e- o, I8 `' _3 d$ z \ v# r- y$ R$ k0 o
My third piece of advice is probably the
/ J" L1 u2 ?1 i0 k$ C7 o. Fhardest to take. It is to forgive yourself for4 {" i* p+ w- d6 B1 p! w
wasting time. Students are only asked to; ^) {4 U& p4 m5 m- m6 i* K
solve problems that their professors (unless( A. h, K& d7 e; j
unusually cruel) know to be solvable. In. D. F0 h; w, ?' e3 A0 b( e
addition,it doesn’t matter if the problems are
+ f |! @3 _, Dscientifically important — they have to be; ^6 m) Q9 _% s- Q
solved to pass the course. But in the real
0 p2 ]# b/ k* O1 C3 Z. o5 P4 a6 Zworld, it’s very hard to know which problems
5 O4 K; |9 T% z: a; l# {3 Bare important, and you never know whether* Y# S3 [9 T) X- D6 c8 _
at a given moment in history a problem is
3 p- [9 `& U; x) jsolvable. At the beginning of the twentieth
5 u' j2 Q; P/ w* g; t7 rcentury, several leading physicists, including/ C, N; R/ x/ @' N: A3 K8 o$ A
Lorentz and Abraham, were trying to work
' P1 o( b# i! @8 k: l; sout a theory of the electron. This was partly, z. e; V* m2 R
in order to understand why all attempts to
" ~( Z$ m7 U, ]2 d Hdetect effects of Earth’s motion through the; P5 U% ?6 }2 [( P1 k6 t
ether had failed. We now know that
* B9 {% _+ I z$ }/ ]$ m8 Jthey were working on the wrong problem.
5 a9 m- m7 ^# l* d5 D: q DAt that time, no one could have developed a
" @; |, Y) \; J; ?! l! usuccessful theory of the electron, because6 o" k& z4 R# {4 C' C8 M
quantum mechanics had not yet been' K! h+ z# v( r. B: m1 w
discovered. It took the genius of Albert
9 K1 _ t ]. M. LEinstein in 1905 to realize that the right/ R5 v0 G# F0 g. q4 y2 q
problem on which to work was the effect
@, x) v- s" Cof motion on measurements of space and3 d( j. }9 _" D- @* t
time. This led him to the special theory of ~7 `3 q/ o0 x% q" |4 w' x! e/ u
relativity. As you will never be sure which9 n4 ^3 b9 i& k
are the right problems to work on, most! X" a( w& ?' F; j* M( d
of the time that you spend in the laboratory
3 [& H" g7 i# {9 Y# ?% @or at your desk will be wasted. If you want
$ z, W: _. q: E( A( mto be creative, then you will have to get used
$ ^* d! S% d9 G' U/ ?to spending most of your time not being
. L* s r# l% D1 x! W& {creative, to being becalmed on the ocean of
& ^( E7 z( k7 W7 w( V5 ]scientific knowledge.# k4 M" _% [! F B
1 Z: z6 o* @: k3 N: b1 e* o9 B
Finally, learn something about the history+ D/ q, k) \' }4 x
of science,or at a minimum the history of your
3 r8 T5 [ G9 b1 N+ cown branch of science. The least important
1 V9 v& g) g4 X4 V3 F3 L3 jreason for this is that the history may actually7 Z1 W% j3 F( E3 c* Q9 ?- I
be of some use to you in your own scientific$ U* ^5 |& W0 @
work. For instance, now and then scientists
9 k# {" b3 p4 ]8 O" b, C/ c) E0 E$ kare hampered by believing one of the oversimplified
' U% C0 ^$ n8 x! _. ?models of science that have( M! R$ _4 r; U N/ L. F* @+ x
been proposed by philosophers from Francis
5 b+ L9 m `+ r: B3 s0 S" dBacon to Thomas Kuhn and Karl Popper.' d$ B+ i$ m, d8 J
The best antidote to the philosophy of science6 ]; `( w' ^" C- Z
is a knowledge of the history of science.
$ s& l9 V9 m& z0 DMore importantly, the history of science9 F* C B8 A3 U+ ]" c
can make your work seem more worthwhile, \; }2 q( f1 Y6 s c
to you. As a scientist, you’re probably not/ F7 A& s! G! V# t! l
going to get rich. Your friends and relatives! T# ~- [2 D6 N; y- ^& c2 m2 L
probably won’t understand what you’re& ~5 Y% h) c; K3 }
doing.And if you work in a field like elementary
, L5 j: B. h$ q1 h/ }particle physics, you won’t even have the4 S- e6 m# z, ~
satisfaction of doing something that is3 _) K' A. U; H5 V5 F1 t3 }
immediately useful. But you can get great
0 a- k5 D+ q" P j; n/ S( N6 Osatisfaction by recognizing that your work in% R: K) f; n+ l2 f. W
science is a part of history., _8 B/ @7 M* V$ n( R
& I$ F0 o0 x$ z
Look back 100 years, to 1903. How
+ P8 z/ g$ k2 `important is it now who was Prime Minister" z' f, F* r$ ?+ I
of Great Britain in 1903, or President of the: J# |5 F: W2 r2 m9 ?% U+ `
United States? What stands out as really/ a$ `$ p$ f# A; ?" W
important is that at McGill University,
" \' @1 }" Q+ u0 y2 BErnest Rutherford and Frederick Soddy were
+ P! H H. I$ L" G/ Zworking out the nature of radioactivity.
% H9 c% e: U- L# L" z% ]This work (of course!) had practical applications,6 O" u3 l7 }+ l [# m, R, T
but much more important were its
4 V7 e: q% h4 F* b; V* Z' m! xcultural implications. The understanding of+ ~+ b2 `( C1 x% W3 W% q9 m" @6 y, c1 j
radioactivity allowed physicists to explain! W+ m+ K1 \. `! v6 I' x
how the Sun and Earth’s cores could still be6 h) j. Q& h6 X, Z
hot after millions of years. In this way, it
* v3 P5 I+ S8 @5 i2 u/ P2 ]removed the last scientific objection to what3 j. D! S R0 ]8 U% \
many geologists and paleontologists1 [ U3 e2 H U. l9 ^+ a0 H
thought was the great age of the Earth and
7 v& h: n4 [& J( i& z p2 cthe Sun.After this,Christians and Jews either
6 K. Q Y/ `3 R/ Ihad to give up belief in the literal truth of5 t& r; {8 B) w6 n
the Bible or resign themselves to intellectual, l* f1 U# Y8 K( J
irrelevance. This was just one step in a
( j$ ^5 f: j1 }) r/ Jsequence of steps from Galileo through3 U- i @" U. g$ H
Newton and Darwin to the present that,time* Y! M) _3 U6 e/ o4 K5 T
after time,has weakened the hold of religious
2 D# A+ x0 o% W6 E: B8 ]dogmatism. Reading any newspaper nowadays! z: A7 l" P7 \/ l
is enough to show you that this work
# H9 L. z- a5 p: i+ O E; mis not yet complete. But it is civilizing work,9 O) T0 V& w7 |, L6 k
of which scientists are able to feel proud. |