Weaver, an American mathematician and one of the founders of communication theory, directed the Rockefeller Foundation's
Natural Science Division from 1932 to 1955, and in this capacity exercised considerable influence over the direction of basic
research in the United States and abroad during the 1930s and 1940s. From 1954 on he was first trustee, then vice president
of the Sloan-Kettering Institute for Cancer Research in New York City (the "Institute" referred to in his letter).
In this letter Weaver expressed doubt that the reductionism at the heart of modern physics was suitable for the study of biology.
Number of Image Pages:
3 (245,049 Bytes)
1964-06-16 (June 16, 1964)
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
About -- as you say -- biologists' biologists. I quite agree that the best molecular biologists do not forget that they
are dealing with living organisms. But there are few of "the best"; and I think that a fair number of the not quite
best do forget. This, however, is not our problem at our Institute; for we have only "the best."
You do agree that we have to move "toward whole cells, tissues, and organisms"; and you agree that the problem is
"how to do it."
Here I suspect that you and I differ. For I do think that it would be useful to have around a person entirely capable of
understanding even the most technical details of what the molecular biologists do, but a person whose orientating background
is quite other. I mean a person who has a vast store of accurate and dependable knowledge about the whole living world, --
who is in a fine and serious and modern sense a student of natural history.
(I was about to write "a naturalist" rather than a "student of natural history." But the dictionary defines
a naturalist as a person who "expands conceptions drawn from the natural sciences into a world view" and who holds
that the "cause and effect laws (as of physics and chemistry) are adequate to account for all phenomena." In other
words, you are a naturalist according to Webster's Third Edition. And "natural history," I find to my dismay,
has now come to connote either an old-fashioned attitude towards nature or an amateurish interest in nature. Must I conclude
that my enthusiasm for a biologist's biologist is as out-of-date as my vocabulary seems to be?)
Why do I think that it would be salutary for us to have a colleague who has a first-hand knowledge of and experience with
the whole world of animals and plants?
It is because I am skeptical as to whether physicists (even reformed physicists) can ever really abandon (or significantly
generalize) the procedures that have served them so well in their own domain. For their successes have essentially depended
upon the facts that, in the realm of inanimate nature, one can successfully
a) isolate a very small part of a great system, and then study that small part without taking any explicit account of the
general system. Physics is the subject in which you can successfully separate variables.
b) restrict that study to the consideration of a very small number of variables (often two and hardly ever more than four).
Physics is essentially not a complicated subject.
c) keep pushing the study to an ever smaller quantitative scale of length, time, and mass. The fun in physics occurs on a
I do not propose to expand my argument, in this letter, to meet all possible objections to the statements just made; but to
indicate that I have not overlooked some important activities that might possibly seem, at first blush, to run counter to
my claim, may I simply state that I think these three points apply to the DNA structure problem (or for that matter to the
general protein structure problem as it is attacked at present), and to cosmological research as well.
There are, of course, some physical problems whose gross features can successfully be analyzed statistically, because they
involve not 4, but say 10^40 variables.
A long time ago I wrote a very simple-minded paper with the title "Science and Complexity." If I were to rewrite
it today I would alter some of the emphasis, but none of the main conclusions. I am sending you a copy herewith.
My net conclusion then is simply this -- that in the effort to work out ways of moving from molecules to man, I think we ought
to have around a person who is aware of larger-scale, more complex, perhaps even more subtle, relations than can be captured
by the small number of variables that so magnificently handle the law of Newton, of Maxwell, of thermodynamics, of Einstein,
of quantum theory . . .