Ethical Considerations 
DISCUSSION 
Medawar: In some sense, the last paragraph of Haldane’s 
paper confounds the rest of it. One of the lessons of history is 
that almost everything one can imagine possible will in fact 
be done, if it is thought desirable; what we cannot predict is 
what people are going to think desirable. In his predictions 
Haldane indulges in a two-fold exercise: saying what he thinks 
is possible, and at the same time saying what he thinks 
is desirable. By what conceivable process can we predict 
what people are going to think desirable even in fifty years 
time ? 
Haldane: We can’t guess what will happen; St. Thomas 
More would have been very surprised to find Mr. Kruschev 
putting some of his ideas into practice. 
Lederberg: For the benefit of any writer who is going to take 
up these ideas (although I don’t think he will express them 
more elegantly than you did, Professor Haldane) I would like 
to point out a blind spot in most of our utopian thinking about 
the modification of man. We seem to prefer to put off the 
problem by talking in terms of the next ten thousand years, 
which is the kind of time-scale on which genetic modification 
could just begin to be plausible. On a very much shorter time- 
scale, we are going to modify man experimentally through 
physiological and embryological alterations, and by the sub- 
stitution of machines for his parts. I wonder to what extent 
it is really worth thinking about genetic modification until we 
have made full use of these other methods. If we want a man 
without legs, we don’t have to breed him, we can chop them 
off; if we want a man with a tail, we will find a way of grafting 
it on to him. 
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