Talking to Zim the other day reminded me of how messy ethics can be. This post will just be me rambling, putting down thoughts in the faint hope they'll fall into some discernable pattern. Read at your peril.

It is clearly morally wrong to push a stranger onto the path of an oncoming vehicle.
It is clearly not morally wrong to be shoved in such a way that you push a stranger onto the path of an oncoming vehicle.
It is a little less clear where the responsibility lies, for placing oneself in such a position that one could be used as an object to push someone in front of a car.
It is clearly morally wrong to kill someone while in a drugged stupor.
It is clearly not morally wrong to kill someone while in a drugged stupor, when the drugging was not voluntary.
It is a little less clear where responsibility lies, for taking drugs such that one eventually ends up killing someone involuntarily.
Are we responsible only for actions done in full consciousness?
Are we responsible for actions done involuntarily, under the compulsion of external forces?
Are we responsible for placing ourselves in such a position that we can fall under these compulsions?

These whittle away at the 'should implies could' principle of moral judgment. It might be the case that you should perform an act, even if you couldn't, given that you were the one responsible for not being able to perform the act in the first place. If you fail to save a drowning baby because you lost the use of your arms in a freak orgy-related incident, would you be responsible for that failure? Does responsibility carry across, from 'cause of cause' to the cause?

I suspect the answer is (annoyingly) 'sometimes.' There are cases, like the aforementioned one, where intuition pushes us in the direction that you are responsible for the results of your voluntary actions, even when those results might be involuntary and undesired. There are other cases where intuition pushes us the other way. Consider the person who tries to save a drowning baby and accidentally triggers a massive whirlpool that consumes a passing ship. He might be the cause of the multiple deaths on the ship, but surely he is not morally responsible.

The task then is to determine where the line is. When does responsibility carry across, and when does it not?

I think the right move is to discard all this as irrelevant, and return to an Aristotelian/Greek concept of goodness. Moral goodness shouldn't be somehow distinct from goodness in general. A good person, in the full sense, would not be shoved into someone, thus sending him to his untimely automobile death. A good person, in the full sense, would not be drugged by enemies such that he then goes on to commit murder. A good person, in the full sense, would not contract any limb-paralyzing disease from random orgies. A good life is the life free of evils such as these. While issues such as responsibility might be interesting to a lawyer (and involuntary acts to a bio-psychologist), they are ultimately irrelevant in the question of how to lead a good life. We need to live with wisdom, and courage, and the rest will follow.