There's an entry in the SEP called "Imaginative Resistance" which goes over an account of a problem with our ability to entertain moral counterfactuals:
The phenomenon of “imaginative resistance” refers to psychological difficulties otherwise competent imaginers experience when engaging in particular imaginative activities prompted by works of fiction. Usually, we seem to have no trouble engaging with time-travel or space-exploration stories, superhero movies, or talking non-human animal fables. At other times, we do not seem to be able to play along that easily; for instance, when we are presented with an alternative Macbeth where
the facts of [Duncan’s] murder remain as they are in fact presented in the play, but it is prescribed in this alternate fiction that this was unfortunate only for having interfered with Macbeth’s sleep. (Moran 1994: 95)
The issue touches on matters like supervenience in ethics and, I suspect, the distinction between, and varying capacities for, counterfactual and counterpossible reasoning (the word "counterpossible" does not show up in the SEP article, however). It reminds me of a doubt I've had about Moorean, or maybe better Rossian, intuitionism about ethics: if, "A is a wrong action," can be denied without contradiction and must be supported, then, by intuition (in the quasi-perceptual sense of the term), then it should be possible to imaginatively entertain a proposition like, "Destroying all possible worlds is a neutral action" (perhaps not ever a right one, though).
Question: but then to what extent, if any, does this phenomenon testify for or against moral fictionalism? Offhand, it seemed to me to be counter-testimony, but upon reflection I came to think that the fictionalist has a powerful response available:
- (Against) If the quasi-truth of a moral proposition depends on what story we happen to be telling, then the possibility of telling a different story would seem to allow for reprogramming our imagination so that it doesn't resist our telling such a story.
- (For) That's the reason for the phenomenon, though: when we imagine the counterfactual world where unrestricted destruction is neutral (or the counterpossible one where it is outright goodX), we are not imagining ourselves in that world, ergo we are not imagining that said world is one where we have been telling a different story than the one we are telling in the real world.
There's a chapter in a book on Nietzsche that is apparently relevant, but to get a copy of it at this time, I'd have to go to a shady search engine and find the book on one of those document-sharing sites (I'll admit that I did that the other day to get a citation for an answer I gave to another poster, here, but I don't want to make a habit of doing so).
XC.f. Anselm's peculiar claim in Cur Deus Homo that if God commanded us to look from left to right, even at the cost of all worlds coming to an end, yet would God's command still hold for us. My first impression of this passage was that Anselm was being overly devout, craven even, but I later wondered if he might have meant his thought experiment as a moment in counterpossible, not just counterfactual, reasoning.