Genes, Brains, and Human Potential The Science and Ideology of Intelligence

294 PROMOTING POTENTIAL

variation is mostly irrelevant. And the output of the genes is highly un-
predictable for very good biological reasons.
As also explained in chapter  4, instead of a “dumb” input- output
machine, what has evolved, even in single cells, is a highly dynamic intel-
ligent system. Such systems can make do with considerable variation in
gene products. Usually, the system can compensate for missing ge ne tic
resources by using an alternative product. Or it can fi nd alternative
pathways to a desired endpoint, as in canalization (chapter 5). Also, the
system can use the same ge ne tic resources to achieve amazing develop-
mental plasticity, even as a lifelong pro cess. Indeed, prob ably the most
in ter est ing aspect of evolution has been the emergence of dynamical sys-
tems, at a number of diff er ent levels, creating and regulating variation far
removed from variation in the genes. And we now know that those intel-
ligent systems can repair or even change the DNA in genes themselves,
in “self- therapeutic” ways, as natu ral ge ne tic engineering.
Th is is, of course, the prob lem encountered in genome- wide associa-
tion studies. Th e direct associations expected cannot be found, resulting
in the so- called missing heritability prob lem. Th ere are other lessons to
be learned there. But it does illustrate the dangers of applying a wholly
inappropriate model to highly complex functions and social contexts. In
chapter  2, I described the prob lem as that of applying pretend genes to
spherical horse prob lems.
Th ere have been other suggestions for promoting potential genet ically.
Th ese are the proposals of the eugenicists, in messages still, alas, not
entirely expunged. In imaginings from Galton through a long line of
followers, the favorable genes can, as it were, be “gathered together” across
generations, and the “bad” genes eliminated. Th at can be achieved, eugeni-
cists have claimed, by vari ous means: selective breeding, marriage control,
sterilization programs, or sequestration (as in asylums). In 1920s Amer-
i ca, sterilization was adopted by several states, some of which infl uenced
Nazi thinkers. In Nazi Germany, as well as the horrors of the Holocaust,
hundreds of thousands of “ mental degenerates” were killed under pro-
grams of euthanasia and infanticide because of assumed “bad” genes.
Th ese are stark reminders of how far ideologically driven science can
take us. But we also need to be reminded that even the more benign, or
therapeutic, plans, can be fanciful— especially when, for the vast major-

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