Hauser and his colleagues have found that people are sensitive to the doctrine of double effect even in thought experiments that don't push their emotional buttons. Even when the dirty work of actually doing the pushing is taken out of the equation, most test subjects say they are more willing to kill someone as a side effect of saving others than to kill that person as a direct means toward that end. And they make this distinction even when they can't explain their preferences afterward.
In his forthcoming book, ``Moral Minds: How Nature Designed Our Universal Sense of Right and Wrong" (Ecco), and in other recent papers, Hauser suggests we may have a moral 'faculty' in our brains that acts as a sort of in-house philosopher-parsing situations quickly, before emotion or conscious reason come into play. Hauser compares this faculty to the mental quality that allows human beings to acquire and use language naturally and effortlessly.
Blood on the Tracks