THE ASSISTANT SECRETARY OF COMMERCE
WASHINGTON, D.C. 20230

 

Dr. Joshua Lederberg

Professor of Genetics

Stanford University School of Medicine
Stanford, California 94305

Dear Dr. Lederberg:

I, too, enjoyed our discussions very much and look forward to
another chance to continue them. In the meanwhile I have been
and will continue to read your writings. The papers you sent
me were most interesting.

The work on the topology of organic chemistry and the use of
linear graph theory to guide computer programming is most
interesting. For aliphatic compounds up to C20 I suppose one
could rely on bigger and bigger computers, but it does seem
to me that the brute force enumeration of all possibilities
reaches a dead end--probably long before C20, even with an
ILLIAC. It would be efficient if there were someway to
incorporate the BADLIST in the main program to inhibit some
aspects of the automatic listing of all possibilities. Of
course you have already probably thought of these ideas.

There is a certain similarity between your methods for
"scoring" the various possibilities (retained by successive
filterings through GOODLIST and BADLIST) and the methods of
multiple hypothesis testing described in my book. (See
especially the program HYPTEST.)

The program is, of course, an example of the general problem
of character recognition. My students and I have had good
luck using Bayesian inference for this purpose.
I also wondered why you did not use some concepts of free
energy more explicitly than in your BADLIST. Sometime in

the late 40's Dr. Mott Souders of Shell Labs published in

1.¢. E.C. (I believe) a table of free energies associated
with various organic substructures. Given a structure it
predicted free energy. If this material were applied to

your listing it would give an initial ranking on free energies
which, I believe, is what the effect of BADLIST really is.

I found your views on risk taking and on the social implica-
tions of biological technology most interesting and quite
close to my own prejudgments. I especially like your choice
of phrases. I know I have a hard time resisting the urge to
be carried away by them and admire your restraint! There is
one other fellow I know who matches you in highly readable
output--and that is my friend Larry Kubie, the psychiatrist.
When we next get together I hope to explore our concern for
moral judgments on technology.

Sincerely,