Gould and Lewontin's (1978) essay, ‘The Spandrels of San Marco’ is famous for faulting adaptationists for not considering alternatives to natural selection as possible evolutionary explanations. One of the alternatives that Gould and Lewontin say has been unfairly neglected is random genetic drift. Yet, in spite of the article's wide influence, this particular suggestion has not produced an avalanche of papers in which drift is considered as an explanation of complex adaptive features such as the vertebrate eye. The reason is not far to seek. Biologists whose adaptationism remained undented by the Spandrels paper continued to dismiss drift as an egregious nonstarter. And even biologists sympathetic with Gould and Lewontin's take-home message—that adaptationists need to pull up their socks and test hypotheses about natural selection more rigorously—have had trouble taking drift seriously. Both critics and defenders of adaptationism have tended to set drift to one side because they are convinced that complex adaptive traits have only a tiny probability of evolving under that process. The probability is not zero, but the consensus seems to be that the probability is sufficiently small that drift can safely be ignored.