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Steven Weinberg+ _3 I; K! e% g( x$ U8 U& N0 _
% W2 O. y/ X- B T# O/ G& ?, `( qSteven Weinberg is in the Department of Physics,
' ~, R3 \0 Q" j, f% vthe University of Texas at Austin, Texas 78712,* c; C B' L' n* M0 V+ c
USA. This essay is based on a commencement talk
+ M! H) F$ T8 b! agiven by the author at the Science Convocation at
" z4 S) U: s+ y6 B$ n8 W# o! B% VMcGill University in June 2003.. y% B$ o& c+ T5 I' s& a
: X$ z' |3 Y# T! |- @( mWhen I received my undergraduate degree — about a hundred years
/ r0 p% A& |6 M2 B5 Kago — the physics literature seemed to me a vast, unexplored ocean,+ ?7 s! C4 h: J
every part of which I had to chart before beginning any research of my own. How( X1 n* n! G2 r# ]6 l4 D7 T3 [
could I do anything without knowing everything that had already been done?7 g& c$ i0 g6 x
Fortunately, in my first year of graduate school, I had the good luck to fall into the2 V5 L# K T4 ~. T. o8 J: Q
hands of senior physicists who insisted, over my anxious objections, that I must start' B& k9 |8 _; d3 \; Q; |- ^( G6 A% l6 y
doing research, and pick up what I needed to know as I went along. It was sink or
?: W- \- `) z6 cswim. To my surprise, I found that thisworks. I managed to get a quick PhD —9 _3 F( a4 h% e& I4 g1 F
though when I got it I knew almost nothing about physics. But I did learn one big; w% F5 }, [0 D" ?* e' S+ t
thing: that no one knows everything, and you don’t have to ." ^8 ~1 J. z) I) S" b+ E
9 o: w7 ]# Q4 F$ FAnother lesson to be learned, to continue: D# M, J6 G9 v |" X/ Q& U
using my oceanographic metaphor, is that
+ a2 \$ i8 y1 h! f& X6 f. ?while you are swimming and not sinking you; C. x: k! D, R+ d0 L z$ K7 J0 ~, F
should aim for rough water. When I was
. a5 P" E+ [' i# ~8 bteaching at the Massachusetts Institute of# D# X3 d$ w4 m: L1 U) @4 \
Technology in the late 1960s, a student told
4 K# X8 |3 o6 A6 A. p$ m3 a, ~* Ume that he wanted to go into general
4 [# g: V0 F6 s; i1 f0 r0 L( w' ?. ]relativity rather than the area I was working$ L1 ~; b$ S3 L* s! }
on, elementary particle physics, because6 o3 {9 M. J4 `5 e
the principles of the former were well
7 o0 U( A$ z# c1 R# ]8 \* xknown, while the latter seemed like a mess: S; s D- E3 Z: J; q
to him. It struck me that he had just given" E* g/ O8 e7 D6 Z# N4 k
a perfectly good reason for doing the opposite.% n- Q" a7 U( O5 p) h
Particle physics was an area where; a: l& `( Y! F- a1 ~! ?* U1 Z! t
creative work could still be done. It really was; b5 T6 C$ T3 C( B
a mess in the 1960s, but since that time the+ t% H1 U, l/ a* u$ Q& n
work of many theoretical and experimental
/ d- _( X7 L9 K ^9 Uphysicists has been able to sort it out, and
- i" j$ p9 ?( @+ c. M) Eput everything (well, almost everything)( \5 R; J) j, x3 w
together in a beautiful theory known as/ M9 E# T& @* _* g! M8 P6 A
the standard model.My advice is to go for the
/ x& w) ^3 X$ T) q: hmesses — that’s where the action is.
% `2 N& {# ]$ X2 {9 x
h( s6 x, j- W9 a1 r. |+ P5 @" ~My third piece of advice is probably the
- F5 H2 R+ u, H$ [2 w" x2 P3 @# Uhardest to take. It is to forgive yourself for
0 N" l/ z; V% _, u; B0 Pwasting time. Students are only asked to
! m3 O" r! B0 k8 g5 ]5 @solve problems that their professors (unless
. f7 R9 p* N5 Punusually cruel) know to be solvable. In- b% H- G- n: _$ b4 L$ f
addition,it doesn’t matter if the problems are
1 }7 W' R% p; M& r+ tscientifically important — they have to be
8 J; v$ }6 N, m4 W6 M: O1 }0 `solved to pass the course. But in the real3 x2 x9 u- T+ A) N# `
world, it’s very hard to know which problems5 H: X$ Q) B% h$ I+ a9 T r! m- v
are important, and you never know whether
O) w- O$ n6 y( ]; l' sat a given moment in history a problem is
( l! d. B8 U$ a& {: j. g( @solvable. At the beginning of the twentieth
- B0 a8 F6 e: x, P# ccentury, several leading physicists, including2 `6 C& y6 {& T; f. ]$ R
Lorentz and Abraham, were trying to work' @6 J2 u& N! J0 m: }" Y3 E* v
out a theory of the electron. This was partly
. v7 G" O0 `# R$ U1 cin order to understand why all attempts to
, Q7 P" A9 y$ G- Y/ C9 l% \detect effects of Earth’s motion through the
$ `9 B! Z- S( f$ b6 nether had failed. We now know that$ J6 Q+ E% j+ b$ k$ F! |% v
they were working on the wrong problem.
' ^( w ~$ j9 P$ zAt that time, no one could have developed a6 p# K' `* y8 h; }3 ?
successful theory of the electron, because& \' C8 [; B2 I+ |4 S# @2 W; w& a7 c
quantum mechanics had not yet been* o2 A9 t6 m5 k \
discovered. It took the genius of Albert1 {' u6 ?; p$ E. s
Einstein in 1905 to realize that the right
% H$ d4 a" `! j9 X3 @problem on which to work was the effect
* E. ^5 Z+ A: h3 T' L, @of motion on measurements of space and: Z# \7 V! s# `* ?9 @! e
time. This led him to the special theory of R7 E9 B/ f' l7 T" o5 j
relativity. As you will never be sure which8 O" E& V. q; `# l* b; A: o
are the right problems to work on, most4 r$ {8 D; f/ R2 x7 D( r. k8 R
of the time that you spend in the laboratory0 k5 I4 I4 ^5 g+ }, x$ U6 o
or at your desk will be wasted. If you want8 r4 ~) m4 i9 F
to be creative, then you will have to get used1 l$ E4 Q) B3 I6 }
to spending most of your time not being
! l- p& _" O4 [/ D" ^creative, to being becalmed on the ocean of: |, G1 U, ^# u
scientific knowledge.
7 W. Q5 @" R/ d h' v$ I; d3 u7 ~) ?# |
Finally, learn something about the history
0 n( e. K& f" t; R" \" P+ l8 Iof science,or at a minimum the history of your
; o, X9 {( o+ L/ z1 S0 I% gown branch of science. The least important
$ f- ^7 O- J, P) rreason for this is that the history may actually
0 [' F6 j1 p$ Z' V) z! {' ^, w7 ibe of some use to you in your own scientific
% N/ X" `6 J& F \* h" Dwork. For instance, now and then scientists; r. |' z2 }) @7 q! d
are hampered by believing one of the oversimplified9 |8 ^5 l- G: w6 m' w
models of science that have3 i ~5 O0 G8 X5 f* e" G
been proposed by philosophers from Francis
) V. R7 ?# F# e1 @) ]1 H r% H6 ]Bacon to Thomas Kuhn and Karl Popper.
0 N% ]/ A/ l+ L) ]The best antidote to the philosophy of science
/ R9 m# V% U# m$ kis a knowledge of the history of science.
3 j$ \0 P* B$ t) S! DMore importantly, the history of science! D3 ?0 q" {$ D! B3 \
can make your work seem more worthwhile3 b) B8 E# [8 H ^
to you. As a scientist, you’re probably not
5 j9 f" Z! z- J6 @* qgoing to get rich. Your friends and relatives
5 W. w/ L+ t- {probably won’t understand what you’re* t+ m1 \, v' O/ X/ O3 T7 m
doing.And if you work in a field like elementary
# Y, D; A: g6 j2 O1 P) [( cparticle physics, you won’t even have the& N: @- M# X# a. u/ m$ f) u; w; Z- z
satisfaction of doing something that is$ @! |' _- t: k6 |4 T
immediately useful. But you can get great
8 c% q/ ] e; I m! w: R5 [2 ksatisfaction by recognizing that your work in
9 ~, J. Q9 X: m2 Wscience is a part of history." a, {) I9 h! O- ^* ~! F$ S
& N u, r1 y; s( _8 NLook back 100 years, to 1903. How4 t( u0 T0 M) [
important is it now who was Prime Minister
. d6 a" v, |' nof Great Britain in 1903, or President of the
v' Z- l5 \# ]United States? What stands out as really& `% O, Q0 b# T9 S. j7 }$ ` b
important is that at McGill University,4 }% T- a ?9 b
Ernest Rutherford and Frederick Soddy were1 h8 v* w1 V4 B" o: j
working out the nature of radioactivity.( {) d* s7 i+ w' }, q
This work (of course!) had practical applications,$ s" ^9 _' d1 Q9 z4 Z$ t
but much more important were its
6 f! \. _% M8 E* c$ s) bcultural implications. The understanding of1 o% ^8 Y+ j2 f% H3 I) |
radioactivity allowed physicists to explain( Y, L! E( ~! y2 t6 B/ f" p
how the Sun and Earth’s cores could still be
. u6 c. Y- t, F: |5 whot after millions of years. In this way, it
* l q! R B' Z/ i$ Y5 }removed the last scientific objection to what( g5 ?& N* L$ D, s2 [$ B
many geologists and paleontologists
! h: a% |8 s6 T% ythought was the great age of the Earth and
- Y0 L$ E' K7 a! t! ?& ithe Sun.After this,Christians and Jews either
( G' q$ \& V/ G6 N; dhad to give up belief in the literal truth of% `% O: U7 n, w& g; i7 V7 i* j
the Bible or resign themselves to intellectual- `: A- j3 Z+ `0 _( L4 C
irrelevance. This was just one step in a* g- `( f% W4 I6 Y
sequence of steps from Galileo through
2 u& O, l* }' [( D T, iNewton and Darwin to the present that,time) Z: Z0 m3 p+ `$ v# N% P
after time,has weakened the hold of religious. n% ?2 @- e$ D' w: m
dogmatism. Reading any newspaper nowadays4 t: ~2 l0 |3 W$ \
is enough to show you that this work
l2 Z9 C9 x3 G2 J! `/ x% }is not yet complete. But it is civilizing work,
; c0 `* J3 T5 t5 [of which scientists are able to feel proud. |