Ross Douthat faces a fascinating (to me) dilemma: the Vatican officially says one thing about the morning-after pill, but Ross believes that the Vatican has reached an incorrect conclusion based on a misunderstanding of reproductive science.
Ross is a Catholic. If a friend said to him that she wants to take the morning-after pill, but is concerned that it might be the moral equivalent of an abortion, so she wanted his recommendation -- what would he be morally obliged to advise?
It seems to me from the Church's perspective, if he advised his friend to take the pill, he would be committing a sin. But what if you, like Ross, honestly believe the Church has erred on the facts? Is an orthodox Catholic -- that is, a Catholic who actually believes that his conscience is bound by the teachings of the Church -- therefore required to counsel what the Church counsels, even if he thinks in good faith that the Church has fundamentally erred? Isn't an orthodox Catholic required, moreover, to believe that the Church teaches truth in matters of faith and morals, and that despite the appearance of error, the individual Catholic is, in fact, wrong?
An orthodox Catholic is required to believe that the Church teaches truly in matters of faith and morals. He is not required to believe that the Church teaches truly in matters of science; indeed, the Church does not have "teachings," properly understood, on scientific questions. Where the two intersect - well, there things get a bit dicey. My sense of that matter is that I am bound to accept the Church's moral judgment that the taking of innocent human life at any stage from conception to natural death is a grave evil (and would not have become a Catholic if I did not), but that I am not bound to accept a Vatican document's summary of where the science stands regarding whether the morning-after pill does in fact take a life, by preventing implantation of a fertilized embryo. And therefore, to take up Rod's hypothetical, if someone contemplating taking the morning-after pill asked for my opinion on the matter, I would tell them that I've seen no persuasive evidence that suggests that emergency contraception is anything save, well, contraception - whose use is sinful according to Catholic teaching, obviously, but not nearly so gravely sinful as abortion. That doesn't mean I would urge them to go take it: It just means that if they asked me if I thought it was an abortifacent, I'd feel obliged to say no.