[Dr John Endler] was travelling on a domestic flight in the United States, and the passenger in the next seat made a conversation by asking him what he did. Endler replied that he was a professor of biology, doing research on wild guppy populations in Trinidad. The man became increasingly interested in the research and asked many questions. Intrigued by the elegance of the theory that seemed to underlie the experiments, he asked Endler what that theory was, and who originated it. Only then did Dr Endler drop what he correctly guessed would be his bombshell: "It's called Darwin's theory of evolution by natural selection!" The man's whole demeanor instantly changed. His face went red; abruptly he turned away, refused to speak further and terminated what had hitherto been an amiable conversation. More than amiable, indeed: Dr Endler writes to me that the man had "asked some excellent questions before this, indicating that he was enthusiastically and intellectually following the argument. This is really tragic."