January 2, 1950.

Dr. E. F. Haskeil,
438 eat 116 Street,
New York 27, N. Y.

Dear Dr. Haskell:

I am very mich afraid that the task of a critical examination of
your presentztion and Dr. Dodd's generalization of coaction theory
is far beyond my means, both of intellectual preparation and of tige.
Because I am entirely unacquainted with your field, even a superficial
reading of the papers has taken mich more time than I can afford to
spend, and I am afraid that even if I spent an unlimited amount of
time and effort on it, I could not give you an informed critdcism.

I think that I understand the main point of your two-dimensional
coordinate system, and to a limited extent, the advantages of expression
in a vectorial as well as a rectilinear form. The rotation of axes that
Dodd proposes had occurred to ma while reading your paper, but it seems
to be a formalism that makes little difference. I think that I would coneur
with Dodd ( and again, this was an anticipation of his remarks) that the
greatest difficulty lies in the fm definition of the "strong" and “weak”
members of the society, the separation of which is basic to your approach.
I am not sure that this is what Dodd does, but my approach to this problem
would be separate the individual memberg, and to express the totality of
his relationships to every other individual. For a predatory individual in
a predator-prey relationship, this would mean n-l terms which in the “pure”
case, would be axr terms G22 and s terms =f where MxEXX rts = n-l ,
and n is the entire population size. These n-l terms would have to be summed
for each of the n individuals (i.e., a total of n(n-1) terms) according to
suitably defined rules. If 1 understand Dodd correctly, the second mement
of the distribution of these terms would provide an objective measure of
the coaction. Howaver, I cannot tell you whether this is what Dodd does,
or whether he does it well. I an certain that the proposal of such a generali-
zation need not imply any disparagement of the coaction theory that underlies
it. To an outsider like myself, Dodd's paper seems rather unclear, but I
did not read your paper without difficulty either, so this judgment is
irrelevant.
For the present, I am notvenclosing the mimeographed material,
in order to expedite the return of the other items. Please let me
know whther you would likes your mimeogranhed naper back.

If reprints of these papers should become available, I would
appreciate receiving copies, so that I can study them at leisure.

Yours sincerely,

Joshua Lederberg
Assistant Professor cf Genetics