[Eighteenth-century Scottish atheist David]Hume was perhaps the first to make the point that we cannot derive "ought" from "is". That is to say, we cannot know how the world ought to be, simply from describing how it is - no matter how knowledgeable we are. Hume's point was later defined with more brutal simplicity by men such as Professor A J "Freddie" Ayer: all statements of ethics are factually meaningless, being no more than the expression of the view that we either like or dislike something.
Freddie (my late stepfather, as it happens) was the Richard Dawkins of his day, at least in the sense that he became this country's most celebrated anti-religious proselytiser; but his impeccable Humean logic is now the impenetrable shield that the churches can use to deflect the ideological bullets of his successor. After all, if religion has been forced to become little other than an assembly of ethical opinions - however passionately adhered to and however elegantly housed-- then it cannot actually be depicted as "wrong".
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