Incompatible reasons for the same action

While writing an earlier post, I came across a curious phenomenon. It is, of course, quite familiar that we have incompatible reasons that we cannot act on all of: reasons of convenience often conflict with reasons of morality, say. This familiar incompatibility is due to the fact that the reasons support mutually incompatible actions. But what is really interesting is that there seem to be incompatible reasons for the same action.

The clearest cases involve probabilities. Let’s say that Alice has a grudge against Bob. Now consider an action that has a chance of bestowing an overall benefit on Bob and a chance of bestowing an overall harm on Bob. Alice can perform the action for the sake of the chance of overall harm out of some immoral motive opposed to Bob’s good, such as revenge, or she can perform the action for the sake of the chance of overall benefit out of some moral motive favoring Bob’s good. But it would make no sense to act on both kinds of reasons at once.

One might object as follows: The expected utility of the action, once both the chance of benefit and the chance of harm are taken into account, is either negative, neutral or positive. If it’s negative, only the harm-driven action makes sense; if it’s positive, only the benefit-driven action makes sense; if it’s neutral, neither makes sense. But this neglects the richness of possible rational attitudes to risk. Expected utilities are not the only rational way to make decisions. Moreover, the chances may be interval-valued in such a way that the expected utility is an interval that has both negative and positie components.

Another objection is that perhaps it is possible to act on both reasons at once. Alice could say to herself: “Either the good thing happens to Bob, which is objectively good, or the bad thing happens, or I am avenged, which is good for me.” Sometimes such disjunctive reasoning does make sense. Thus, one might play a game with a good friend and think happily: “Either I will win, which will be nice for me, or my friend will win, and that’ll be nice, too, since he’s my friend.” But the Alice case is different. The revenge reason depends on endorsing a negative attitude towards Bob, while one cannot do while seeking to benefit Bob.

Or suppose that Carl read in what he took to be holy text that God had something to say about ϕing, but Carl cannot remember if the text said that God commanded ϕing or that God forbade ϕing—it was one of the two. Carl thinks there is a 30% chance it was a prohibition and a 70% chance that it was a command. Carl can now ϕ out of a demonic hope to disobey God or he can ϕ because ϕing was likely commanded by God.

In the most compelling cases, one set of motives is wicked. I wonder if there are such cases where both sets of motives are morally upright. If there are such cases, and if they can occur for God, then we may have a serious problem for divine omnirationality which holds that God always acts for all the unexcluded reasons that favor an action.

One way to argue that such cases cannot occur for God is by arguing that the most compelling cases are all probabilistic, and that on the right view of divine providence, God never has to engage in probabilistic reasoning. But what if we think the right view of providence involves probabilistic reasoning?

We might then try to construct a morally upright version of the Alice case, by supposing that Alice is in a position of authority over Bob, and instead of being moved by revenge, she is moved to impose a harm on Bob for the sake of justice or to impose a good on him out of benevolent mercy. But now I think the case becomes less clearly one where the reasons are incompatible. It seems that Alice can reasonably say:

1. Either justice will be served or mercy will be served, and I am happy with both.

I don’t exactly know why it is that (1) makes rational sense but the following does not:

2. Either vengeance on Bob will be saved or kindness to Bob will be served, and I am happy with both.

But it does seem that (1) makes sense in a way in which (2) does not. Maybe the difference is this: to avenge requires setting one’s will against the other’s overall good; just punishment does not.

I conjecture that there are no morally upright cases of rationally incompatible reasons for the same action. That conjecture would provide an interesting formal constraint on rationality and morality.