Assuming there is no afterlife, or whatever afterlife there is does not depend on the morality of my actions in this life, what is one’s incentive to be moral given basic rational self-interest is often at odds with choosing to be moral?
An afterlife where I am rewarded/punished for the moral/immoral actions I choose to take in this life makes sense in accord with basic rational self-interest. It is in my best interest to act morally because I am rewarded for doing so. But lacking this and observing the frequency choosing moral actions does not serve my self-interest, I am wondering how philosophers of morality or ethics argue why I should care about morality or ethics in the first place.
*Self-interest precludes negative legal repercussions. For example, I am asking what my incentive is to avoid an immoral act which benefits me but is still legal or I know a legal authority cannot discover (it is in my self-interest to avoid punishment).
Update Notes in Response to Comments
I am not presuming self-interest is always rational. I am not presuming what is rational serves self-interest. I am only presuming there is a such thing as self-interest and that there are many situations where a rational and thorough analysis leads to the conclusion I can overall benefit from doing something immoral. Then I am asking what is the incentive to be moral in these cases.
Why should I do the right thing in cases where doing the wrong thing clearly benefits me more than harms me? From the comments and answers, some people seem to believe this is contrived. However, I would argue this is the most commonplace immorality. Consider garden-variety exploitation by wealthy and powerful people. Most seem to agree this is at least somewhat commonplace across the planet, especially due to its legality. Politicians lying and manipulating, as well as being rewarded in certain ways by legal but shady special interest groups, is another common example.
Why should these people care that what they are doing is wrong when the benefits exceed the negative repercussions? They know this more than anyone because they choose to continue to do these things. These people don’t seem to care very much about the morality of their actions. What is the incentive for them to be moral? Why should they care about morality? By extension, why should anyone in similar circumstances (benefiting from immorality)?
Many of the comments indicate violating moral principles simply does, more often than not, entail negative repercussions that outweigh the positives. I don’t see much widespread evidence for this, especially from my examples. Such people can stop whenever they want, yet choose to continue. I also do not see evidence such people suffer more than the average population. In fact, they seem to be very well admired, connected, and cared for.