Perhaps some of you Thomists (if you’re still reading this blog) can shed some light on this. A few weeks ago there was a discussion on another blog in which the question of double effect came up. A Catholic was defending the principle that one may not directly intend an act which is intrinsically wrong. He used the example of surgery for an ectopic pregnancy, which of course is technically a form of abortion. The traditional justification for this, as I understand it, is that the abortion is not what is directly intended.
The Catholic was challenged by a skeptic (an atheist, I think), who wanted to know why this couldn’t be used to justify all sorts of things. I’m not sure where the discussion went after that, because he brought up another case: would it be right to shoot down a hijacked airliner full of passengers to prevent a 9/11-type attack? The intent is to stop the plane from being used as a weapon, not to kill the passengers, although their deaths are a foreseeable and all but inevitable consequence.
What about it? Would this be morally licit? I confess I have never been altogether at ease with some of the reasoning used to preserve, in certain hard and extreme cases, the principle that one may not intend evil. It sometimes seems like saving the appearances.