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MAY 14 1969
Princeton University PALMER PHYSICAL LABORATORY
DEPARTMENT OF PHYSICS
POST OFFICE BOx 708

PRINCETON, NEW JERSEY 08540

12 May 1969

Dr. Joshua Lederberg
Department of Genetics
Stanford University
Stanford, Calif. 9305

Dear Josma,
Thank you very much for letting me have a copy of your article in the WASHINGTON

POST. May I send you in return a copy of my paper in the PROCEEDINGS OF THE
AMERICAN PHYSICAL SOCIETY as soon as they arrive.

Mui ~~ Let me tell you in the meantime that I cannot share your optimism concerning

NY

the explanation of the phenomenon of life in terms of present-day physics.

If I look back into the past, I realize that the existence of an electromagnetic
field could have been denied with arguments very similar to those now being
advanced to claim the applicability of present-day physics to life. After all,
nothing "exhibits tissues or functions that would except these" from being
analyzed in terms of old-fashioned mechanics. In addition, it seems to me

that it is not entirely modern to believe that the present completely determines
the future. Modern quantum mechanics surely contradicts the idea of complete
causality.

I realize that abstract statements of this nature won't convince any biologist,
and it would be nice indeed if we could understand each other's point of view
better. When I next get to Stanford, I will try to get hold of you for a dis-
cussion of these points. :

Concerning your question: I believe it was Elsasser who first suggested that

a computing machine large enough to take in all the complexities of a large
living body would need more material than is contained in the universe.
Greidanus, in various articles of the Dutch Academy expresses and supports the
same thought -- I don't recall whether or not independently of Elsasser. These
thoughts also seem to me to speak against the possibility of explaining life in
terms of present-day physics, but I do not quite agree with them. Abstract
reasoning can often outdo machines, and it would be obviously entirely impossible
to prove the uniqueness of the decomposition of all numbers into primes by a
straightforward application of calculating machines.

It was a pleasure to hear from you.
Sincerely, -

le Ca <

Eugene P. Wigner

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