I've been thinking about comparing degrees of reponsibility, and then it hit me that there are two kinds of degrees of responsibility. Start by dividing responsibility first by the kinds of norms that are being brought to bear on the evaluation. So we have moral, aesthetic, legal, epistemic, etc. responsibility. Within each of these "normative types" of responsibility we may wish to evaluate the degree to which one is responsible. And it is here that there are the two interesting types that I have been thinking about.
Consider what one might call "merely causal responsibility." This is not a normative notion, and it is not a kind of responsibility in the above sense. But it will be suggestive to think about it. There are two dimensions along which we may measure merely causal responsibility: necessity (N) and sufficiency (S). Degrees of necessary causal responsibility (causal N-responsibility) measure just how necessary the cause was to the effect—how much of a difference the cause made to the effect. Degrees of sufficient causal responsibility (causal S-responsibility) measure how much of the effect was accomplished by the cause. Roughly, a substance cause is N-responsible to the degree that it could have easily prevent the effect, that it made a large difference to its being the case that the effect, rather than some relevant alternative, occurred. And a substance cause has S-responsibility to the degree that it is difficult for other cause to prevent the effect, that other things made a small difference to its being the case that the effect, rather than some relevant alternative, occurred.
There is a suggestive, though rough, formal relationship between S- and N-responsibiity. Thus, x's S-responsibility for E inversely covaries with other things' N-responsibility for E, and x's N-responsibility for E inversely covaries with other things' S-responsibility for E. Thus, it is not possible that x has maximal S-responsibility for E while y, distinct from x, has maximal N-responsibility for E. But it is possible that both x and y has maximal N-responsibility for E—think of how each parent has close to maximal, or maybe even maximal, causal N-responsibility for the child's existence. And likewise it is possible that both x and y has maximal S-responsibility for E—think of two sharpshooters each of whom hits the victim in the heart.
Roughly, N-responsibility goes with preventability and S-responsibility goes with achievement.
Now, there are similar such types of degrees of normative responsibility. The degree of one's S-responsibility for E measures how much E counts an achievement of one's own, how much one's name can be inscribed on E, in respect of the relevant norms, how little others have N-responsibility for E. The degree of one's N-responsibility for E measures how much one is to be treated as having made a difference in respect of E, how little others have S-responsibility for E. These aren't definitions—I am simply sketching some suggestive ideas that I don't have fleshed out.
Among the following, I am inclined to think the claims about moral N-responsibility are true, perhaps given some provisos about knowledge, but I am not sure about the ones about moral S-responsibility:
- One's moral N-responsibility for a conjunctive state of affairs is at least as great as one's moral N-responsibility for the conjunct that one is most morally N-responsible for.
- One's moral N-responsibility for a disjunctive state of affairs is at most as great as one's moral N-responsibility for the disjunct that one is least N-responsible for.
- One's moral S-responsibility for a conjunctive state of affairs is at most as great as one's moral S-responsibility for the conjunct that one is least morally S-responsible for. (?)
- One's moral S-responsibility for a disjunctive state of affairs is at least as great as one's moral S-responsibility for the disjunct that one is most morally S-responsible for. (?)
Here is an interesting thing. In the case of moral responsibility for evil, N-responsibility counts for a lot. Being an essential cog in the production of an evil is really bad. But in the case of moral responsibility for good, N-responsibility counts for much less, though S-responsibility counts for a lot. Being an essential cog in the production of a good is not as good as it is bad to be an essential cog in the production of an evil.
Next, here is an interesting question: When compatibilists and incompatibilists are talking about what one is responsible for, are they perhaps confusing N- and S-responsibility sometimes? Since N- and S-responsibility seem to differently relevant in the case of goods and evil, it may make a difference whether one's intuitions are driven by cases of good actions or cases of evil actions. Evil actions are, I think, the more commonly discussed in the literature, which pushes the discussion towards N-responsibility.
Here is my intuition, one that I think a lot of incompatibilists have. If C is a sufficient cause of E, then one is no more morally N-responsible for E than one is for C. (One might also conjecture that if C is a necessary cause of E, then one is no more morally S-responsible for E than one is for C. But I am less sure about this, for the same reason that I am not sure about the bulleted claims about S-responsibility above.) If this is true, then something like incompatibilism about N-responsibility follows if there is no backwards N-responsibility. For if causal determinism holds, then the precise state of the universe prior to my conception is a sufficient cause of everything I am a cause of, and hence I am no more morally N-responsible for anything I am a cause of than I am morally N-responsible for the precise state of the universe prior to my conception. And it is plausible that I am not at all morally responsible for the precise state of the universe prior to my conception.