This is an edited version of a response I made to another student's post on the HUM331 forums (originally discussing the implications of suicide). This is just my personal answer; see my other post for relevant textual views on the more general question of what persists after death.

Although Buddhists often talk about karma and rebirth as literal fact, can we consider them to be mythological or metaphorical? If so, can we base our present actions on the assumption these actions will not lead to suffering (or whatever karmic effects) after death, since we will no longer exist after death and cannot be subject to karma?

Buddhists also talk about the self in a single lifetime even though non-self is a fundamental teaching. Although it may be fair to call rebirth mythological or metaphorical, it isn't clear that it is fundamentally any more or less mythological or metaphorical then the provisional belief in moment-to-moment continuity of the self.

As for whether or not our present actions cause suffering (etc.) after death, the view that they do not cause suffering because we no longer exist assumes not only that rebirth is "metaphorical", but also that one's own suffering is the principle concern. If one stops acting out of self-centredness, then there is no reason to see one's own suffering or karma as distinct from anyone else's. The various causes and conditions set by actions in one's current life go on to affect other beings in the future regardless of whether one is personally still in existence in any sense. In this context it doesn't seem particularly significant whether there is or isn't personal rebirth.

That said, many Buddhists do seem to focus on personal karma, and that view can and does lead to weighing perceived costs of actions against each other in terms of future personal suffering.