History: Shut up and calculate!

Abstract

Practical, interdisciplinary ways of working forged during the Second World War had a lasting impact on a generation of physicists and their findings, says David Kaiser.

Full text

BIAS Studies of gender and
research impact should
exclude self-citations p.160
MUSIC In conversation with
an artist inspired by his
own tinnitus p.159
BRAIN A compelling personal
take on the science of
anxiety p.157
MILITARY Two views of the
changing impact of science
on warfare p.156
even faster. Again building on early insights
from a British team, the Manhattan Project,
coordinated from the Los Alamos laboratory
in New Mexico, ballooned to encompass
125,000 people working at 31facilities across
North America. By the time the atomic
bombs were dropped on Hiroshima and
Nagasaki in August 1945, the project had
cost $1.9billion (about $25billion today)
2
.
Together, the radar and atomic-bomb pro-
jects amounted to about 1% of US military
expenditure during the war: modest on the
scale of defence appropriations, but utterly
unprecedented for the academic scientists
and engineers caught up in the war projects.
And it was more than just the
Within weeks of Compton’s call, a skeleton
staff at the Rad Lab was hard at work try-
ing to improve on a British-designed cavity
magnetron, which they hoped could become
the centrepiece of a type of short-wavelength
radar. When the laboratory began operation
— more than a year before the United States
entered the Second World War — the staff
consisted of 20physicists, three security
guards, two stockroom clerks and a secre-
tary. By the war’s end, the lab had swollen
to 4,000 people and was managing develop-
ment contracts worth US$1.5billion (nearly
$20billion in 2013 dollars)1.
The Allied nuclear-weapons project,
code-named the Manhattan Project, grew
Shut up and calculate!
Practical, interdisciplinary ways of working forged during the Second World War had
a lasting impact on a generation of physicists and their findings, says David Kaiser.
O
n 17 October 1940, Karl Compton,
president of the Massachusetts
Institute of Technology (MIT) in
Cambridge, made a hasty telephone call
from WashingtonDC to a colleague back
on campus. Could MIT spare some modest
space to host an urgent, top-secret defence
project? After making some quick assess-
ments, Compton’s assistant reported that
MIT could shuffle some other laboratories to
accommodate the facility. With that phone
call, the Radiation Laboratory, or ‘Rad Lab’,
was born. The laboratory had an enormous
impact on the course of the Second World
War. Arguably, its impact on science was
even greater.
Physicists Edward Bowen (left), Lee DuBridge (centre) and I. I. Rabi work on a cavity magnetron in the 1940s.
MIT MUSEUM
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© 2014 Macmillan Publishers Limited. All rights reserved

budgets that grew. In both projects,
physicists, chemists, metallurgists and their
colleagues found themselves working in huge
groups with larger-than-life equipment. Is o-
tope-separation plants in Oak Ridge, Tennes-
see, stretched the length of a city block; the
nuclear-reactor facilities in Hanford, Wash-
ington, required more than half a billion
cubic metres of concrete.
After the war, many physicists dismissed
their work on such sprawling wartime pro-
jects as temporary distractions: an important
but limited hiatus from their ‘real’ scientific
research. One Rad Lab veteran even com-
posed a song soon after the war closing with
the memorable line, “Oh, dammit! Engi-
neering isn’t physics, is that plain? Take, oh
take, your billion dollars, let’s be physicists
a g a i n ”. 3
Despite the songwriter’s plea, scientists
did not return to the antebellum status quo.
Instead, many characteristics of the wartime
projects became the new normal, even in
peacetime. The war cast a long shadow on
how science is organized and funded, and
even on the methods and questions that many
scientists pursued throughout their careers.
COMMON PURPOSE
Until the war, most scientific research in the
United States had been supported by private
foundations, local industries and under-
graduate tuition fees. After the war, scien-
tists experienced a continuity — even an
expansion — of the wartime funding model.
Almost all support for basic, unclassified
research (as well as for mission-oriented
defence projects) came from the federal
government.
In 1949, 96% of all funding for basic
research in the physical sciences in the
United States came from defence-oriented
federal agencies, including the Department
of Defense and the then-new Atomic Energy
Commission, successor to the Manhat-
tan Project. In 1954 — four years after the
establishment of the civilian US National
Science Foundation — 98% of funding for
basic research in the physical sciences came
from federal defence agencies. And the scale
of funding was unlike anything before the
war. By 1953, funding for basic research in
the United States had leapt to 25 times what
it had been in 1938 (in constant dollars,
adjusting for inflation)4. The fire hose of
federal spending paid for all kinds of inter-
esting research.
Much of the work was conducted in insti-
tutions modelled on wartime examples.
Defence projects during the war had thrown
together experts from many different fields
of science and engineering to work towards
common objectives, rather than grouping
specialists by disciplines. The enormous
time pressures and shared goals of war
work forced scientists and engineers to craft
effective means of communicating with each
other. Mathematical rigour and abstruse
theoretical derivations were worth little if
colleagues from other specialities could not
build on the results.
Veterans of the intense, multidisciplinary
wartime projects came to speak of a new
type of scientist. They touted the war-forged
‘radar philosophy’ and the quintessential ‘Los
Alamos man’: a pragmatist who could collab-
orate with everyone from ballistics experts to
metallurgists, and who had a gut feeling for
the relevant phenomena without getting lost
in philosophical niceties5.
Leading scientists and policy-makers
actively sought to continue the wartime
spirit of collaboration across disciplines.
The Atomic Energy
Commission over-
saw a new network
of national laborato-
ries to pursue both
civilian and defence
research. The labs
featured interdiscipli-
nary teams that mixed
physicists, mathematicians and chemists
with engineers of many stripes6. A similar
set-up appeared across dozens of US univer-
sities: facilities straddling several academic
departments, such as the Research Labo-
ratory for Electronics and the Laboratory
for Nuclear Science and Engineering, both
founded at MIT by the end of 1945 (ref.7).
The facilities hummed with surplus equip-
ment and know-how culled from the wartime
projects. Physicist Bruno Rossi, for one, stud-
ied cosmic rays after the war by adapting the
sensitive timing circuits he had built at Los
Alamos to measure nuclear-fission rates5.
Similarly, just months after the end of
hostilities, self-described ‘boffins’ who had
spent the war working on radar turned their
attention to the impossibly small and the
cosmically large. Some began to build radio
telescopes and aimed them at the heavens.
An international community coalesced,
linking the Jodrell Bank telescopes near
Manchester, UK, and the Parkes telescope
in New South Wales, Australia, to similar
instruments dotted across North America
— from the California Institute of Tech-
nology in Pasadena to the National Radio
Astronomy Observatory in Green Bank,
West Virginia8. And in 1947, using repur-
posed microwave-frequency electronics left
over from his wartime radar work, physicist
WillisLamb of Columbia University in New
York measured a tiny shift — of about one
part in a million — in the energy levels of an
electron in the 2s and 2p orbitals of a hydro-
gen atom. Lamb’s remarkable achievement
challenged physicists’ prevailing under-
standing of the vacuum — the mysterious
state of lowest-possible energy9.
One of the first to hear about the Lamb
shift was physicist JulianSchwinger, who
before the war had been a rising star in
quantum theory. Like so many physicists at
the Rad Lab, Schwinger had been forced to
rethink his approach to calculation. Elegant
derivations from first principles — which
often proved tractable only when applied
to idealized situations — were of little value
to the many colleagues who needed to fine-
tune electronics components for maximum
efficiency. Instead, as Schwinger himself later
recalled, he internalized from the engineers a
Julian Schwinger (standing) with colleagues at MIT’s Radiation Laboratory during the Second World War.
MIT MUSEUM
“This war-
forged
pragmatism
produced
enormously
impressive
research.”
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modular, ‘effective circuit’ approach. Rather
than calculate the total electrical resistance
of a complicated component from the lofty
heights of Maxwell’s equations, he could
‘blackbox’ each component, substituting its
overall resistance as determined from meas-
urements of inputs and outputs. The niceties
of how current flowed between constituent
parts of a given component mattered much
less to the main objective — improving radar
designs — than did the effect of that compo-
nent in a given circuit5,9.
Schwinger approached the Lamb shift
with his Rad Lab lessons still fresh. Since the
1930s, senior theorists had tried to calculate
the effects of subtle quantum fluctuations
from first principles. Maddeningly, their
equations always broke down, producing
unphysical infinities instead of finite answers.
Schwinger rearranged his equations in terms
of measurable inputs and outputs, just as his
engineering colleagues at the Rad Lab had
done with real-world electronics. By recast-
ing the calculation, Schwinger managed to
calculate the effects of quantum fluctuations
on the electron’s energy levels and obtain an
answer that matched Lamb’s measurement
to an extraordinary precision. As it turned
out, Japanese physicist Sin-ItiroTomonaga
had accomplished the same goal a few years
earlier. Tomonaga’s work on radar during
the war had proven similarly essential to his
theoretical approach5,9.
PHILOSOPHY RETURNS
This war-forged pragmatism produced
enormously impressive research and influ-
enced a generation of leading scientists.
Their approach to basic research — and
the institutions in which they pursued it
— assumed an aura of inevitability. But the
approach came with some trade-of fs, largely
unnoticed at the time. Important questions
that resisted the powerful, phenomenologi-
cal methods tended to get eclipsed. Any-
thing that smacked of ‘interpretation’, or
worse, ‘philosophy’, began to carry a taint
for many scientists who had come through
the wartime projects. Conceptual scrutiny
of foundations struck many as a luxury. The
wartime style was reinforced in the United
States by exponentially rising university
enrolments after the war. The new classroom
realities left little space for informal discus-
sion of philosophy or foundations. The Rad
Lab rallying cry of “Get the numbers out”
shaded into “Shut up and calculate!”10
By the mid-1960s, three-quarters of each
year’s crop of physics PhD graduates in the
United States specialized in either nuclear
physics or solid-state physics: two impor-
tant and interesting areas, to be sure, but also
those most readily funded by defence agen-
cies (even for unclassified, basic research).
They were also areas in which most physi-
cists came to agree that a pragmatic style
could yield the greatest success. During this
period, for example, physicists first under-
stood the nuclear force that causes radio-
activity, and conquered strange phenomena
such as superconductivity — both Nobel-
prizewinning achievements.
Openly philosophical areas of physics,
the intellectual roots of which stretched
back before the war, became increasingly
marginalized, such as grand questions
about the birth and fate of the Universe, the
thin border between order and disorder in
chaotic systems, or the subtle foundations
of quantum theory. Sometimes these were
denigrated as not even being ‘real physics’
by influential physicists in the United States,
although research in these areas advanced in
other parts of the world10.
A quarter of a century after the end of the
Second World War, cracks in the system
began to show. The escalation of fighting
in Vietnam made many people question
the dominant place of military funding on
university campuses, and difficult economic
conditions further drove a rapid reversal of
fortunes in the sciences, and in physics in
particular. Job opportunities for those with
science PhDs fell sharply, and university
enrolments quickly followed suit, none more
drastically than in physics.
The organization, funding and basic
approach to research that had come to
seem normal — even inevitable — after
the war were no longer taken for granted.
Complementary styles of research began
to creep back in, and growing numbers of
physicists turned to topics that had seemed
beyond the pale just a few years earlier, such
as cosmology, chaos theory and quantum
entanglement10.
Radar philosophy and the Los Alamos
man did not disappear from view. To this
day, most basic research in the United States
depends on federal funding, and many of
the great successes of the postwar genera-
tion — such as the standard model of parti-
cle physics — remain mainstays of research
and teaching. But that legacy now sits beside
more recent breakthroughs born of the era
that reclaimed more openly speculative
and philosophical approaches to the deep
mysteries of nature. ■
David Kaiser is professor of the history
of science and department head for the
Program in Science, Technology, and Society
at the Massachusetts Institute of Technology,
Cambridge, Massachusetts.
e-mail: dikaiser@mit.edu
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Students protest against military research at the Massachusetts Institute of Technology in 1969.
AP
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