But don’t values still fall short of the standard of rationality by which we measure beliefs? Appiah replies that even a person’s beliefs are only rational relative to the beliefs he already possesses. It is no more irrational for a member of the Asante clan to believe that his aunt’s illness is caused by her daughter-in-law’s witchcraft than for a person in Manhattan to believe that a virus is responsible. The westerner does not see viruses invading cells any more than the Asante sees witches producing their malign effects. When scientists looked at photographs of cloud chambers they saw fuzzy lines which it was rational to interpret as the paths of electrons only because of prior theoretical beliefs. Appiah concludes that “you can’t get into the game of belief by starting from nothing”. However, he rejects the view that we cannot adjudicate between beliefs in witchcraft and viruses. The former, he declares, are false, the latter true; the theories and ideas of science are “far superior” to those of pre-scientific societies. By Appiah’s own reckoning, this judgment is rational only relative to the beliefs he already possesses.
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