   It would be interesting to hear the outcome of experiments to see whether people’s intuitions about prima facie duty are subject to change on morally irrelevant grounds. This is something that requires empirical testing, but it is hard to imagine someone thinking that the fact that one would have to kill an innocent person in order to save five didn’t count against doing this act, or that the fact that their act would save five innocent people didn’t count in favour of it, regardless of their overall verdict about whether they should kill the one or let the five die. That their act involved physically pushing someone in front of the trolley, or pulling a lever that would release a trap door dropping them onto the track would plausibly make no difference to such intuitions. Nor would framing effects introduced by the order of presentation of the cases. If such a priori expectations are correct then empirical psychology would raise no problems for a Rossian intuitionism that claims only that principles of prima facie duty are self-evident.