There are two ways of drawing a distinction between moral and epistemic reasons:
What kind of value grounds the reasons (epistemic or moral).
What kind of thing are the reasons reasons for (e.g., beliefs vs. actions).
If we take option (1), then there will be epistemic reasons not merely for beliefs, but for actions. Thus, the scientist will have epistemic reasons for doing a particularly informative experiment and the teacher may have epistemic reasons for engaging the students in a certain didactically beneficial group activity—i.e., in both cases, epistemic goods (to self and/or others) justify the action.
I like option (2). Moral reasons are reasons for action, while epistemic reasons are reasons for having a belief or credence or the like.
Here are some reasons for not drawing a distinction between reasons for action in terms of the kind of value as in (1).
First, we would morally admire someone who sacrificed a well-paying and easy career option to become a science teacher at an inner city school in order to pass the gift of knowledge to students. In other words, our admiration for someone who at significant personal cost promotes an epistemic value (by otherwise morally upstanding means) is moral.
Second, if we distinguish moral and epistemic reasons for action, consider conflicts. We would have to say that a scientist may have moral reasons to come home on time to feed her hungry children, and epistemic reasons to complete an experiment that cannot be done at another time. But now whether it is right to come home on time or to complete the experiment depends on the details. If the information gained from the experiment is unimportant while the experiment will take hours, and the kids are very hungry, coming home on time is right. But if the children are only very slightly hungry, and the experiment would only protract this hunger by a few minutes, while being extremely illuminating, staying a few minutes may well be the right thing to do.
Right in what way? Well, I think once again the kind of praise that we would levy on the scientist who balances their epistemic goals and their children’s needs well is moral praise. But then the moral praise does not always align with what I have been assuming are moral reasons for action. For we would not morally praise the scientist who neglects a short but extremely illuminating observation in order to make their children dinner a few minutes earlier. Such a scientist would have an insufficient love of epistemic goods. The scientist who hits the right balance is morally praiseworthy. Yet it is very odd to think that one is morally praiseworthy for subordinating moral reasons to non-moral ones!
If you’re not yet convinced by this case, consider one where the moral and non-moral goods are to the same person. A parent is explaining some very interesting matter of science to a child. The child would rather eat a few minutes earlier. If there really is a moral/epistemic reason distinction in actions, then the parent’s reasons for explaining are epistemic and the reasons for feeding are moral. But it could be morally praiseworthy to finish out the explanation.
Third, there are multiple kinds of non-epistemic good: health, virtue, appreciation, friendship, etc. The heterogeneity between them does not appear to be significantly less than that between all of them taken together and the epistemic goods. It seems that that if we are cutting nature at the joints, there is no reason to posit a particularly significant cut between the epistemic and non-epistemic goods. Instead, we should simply suppose that there is a variety of types of good, such as maybe health, virtue, beauty, friendship and understanding (and almost certainly others). All of these are alike in being goods, and different from each other as to the fundamental kind of good. To give the honorific “moral” to all of the ones on this list other than understanding seems quite arbitrary.
On the other hand, the distinction as to the type of thing that the reasons are reasons for does seem quite significant. Reasons for action and reasons for belief are quite different things because we respond, or fail to respond, to them quite differently: by willing and by believing, respectively.
It is interesting to ask this question. If the will has moral reasons, and the intellect has epistemic reasons, are there other faculties that have other reasons? Maybe. We can think of a reason R for ϕing in a faculty F as something that has a dual role:
it tends to causally contributes to ϕing within F
its presence (and causal contribution?) partially grounds ϕing counting as an instance of proper activity of F.
(Thus, reasons are causes-cum-justifiers.)
Are there things like that for other faculties F than will and intellect? Yes! The presence of a certain bacterium or virus may be a reason for the immune system to react in certain way. Humans thus have moral, epistemic and immune reasons, distinguished respectively by being reasons for the will, the intellect and the immune system. And there are doubtless many more (e.g., I expect there are reasons for all our sensory systems’ identifications of stimuli).
Some of these reasons are tied to specific types of goods. Thus, epistemic reasons are tied to epistemic goods, and immune reasons are tied to health goods. But moral reasons are different, in that action has a universality about it where any type of good—including epistemic and health ones—can ground a moral reason. And both epistemic and moral reasons tend to be different from immune reasons in that in the normal course of immune functioning we do not process them intellectually, while both epistemic and moral reasons are intellectually processed in normal use.