Eugenics and Genetics 
because I really do not understand what problem you are 
trying to solve. If you are trying to upset violently the present 
gene frequencies in the population, then nothing that Muller 
proposes could do this. Just as Haldane has shown long ago 
that sterilization of the unfit would hardly have any influence 
on the proportion of recessive genes, so the multiplication of 
what we choose to call the fit can really have very little effect on 
the presence of recessives. (And no one who has known the 
children of accepted geniuses would suppose that the population 
would greatly benefit by there being several hundred of them.) 
If you are trying radically to change the gene frequencies, of 
course you can only do that in Crick’s way, that is by forcibly 
preventing all but a few genes from reproducing. Even this 
supposes that you know (a) why you think a particular gene 
is good, and (b) what tests to apply in order to identify it. 
However, I took Crick’s remarks to be a reductio ad absurdum 
of the method of direct control of the gene frequencies. Indeed, 
we might achieve the same effect in a simpler way—by eating 
the children of the unfit, as Jonathan Swift suggested that the 
Irish poor should eat their own children. But what problem 
are we trying to solve? What genes are we trying to boost? 
Muller asserts in his paper that there are reasons to believe that 
the human population is deteriorating, and Huxley in one 
phrase in his paper also implied this. I know of no evidence for 
that. I know of no evidence that the present human population 
is inferior, in any respect that one could quantify, to the human 
population 50 years ago. On the contrary, the only important 
experimental test of this assertion—the experimental intelli- 
gence testing of Scottish children which has been carried out 
over the past 25 years—produced exactly the opposite results. 
The human race seems to be improving itself by those natural 
means which I propose to continue to enjoy so long as I can! 
MacKay: I have been thinking of Shaw’s mischievous re- 
mark: “‘What has posterity done for me that I should do any- 
thing for posterity?’’ Since the relation between individual 
responsibility and that of “‘society’’ is in fact still unclear, 
the notion of “‘our”’ responsibility to tinker with the genetic 
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