It’s taken to be a platitude of folk morality that I can only be morally responsible for my own actions. Call this The Platitude. Sometimes The Platitude is presented in a more expansive form: (a) I can be responsible for my own actions; and (b) I cannot be responsible for anyone else’s actions. This platitude is then taken to entail what I’ll call The Slogan: moral responsibility presupposes personal identity. Classical philosophers who have embraced The Slogan include Locke, Reid, and Butler, and contemporary philosophers who do so include DeGrazia, Glannon, Haksar, Madell, Parfit (on one reading), Schechtman, and Sider. Nevertheless, The Slogan is false. Responsibility doesn’t presuppose identity, even if The Platitude is true.
What I say here will be extremely compressed, so feel free to demand details. In this post I will be concerned only with those authors who believe that responsibility presupposes numerical identity, that the earlier Φ-er and the later person responsible for Φ-ing must be one and the same person or individual. This is in fact the view held by all the authors just mentioned. Now some may object that Schechtman, for instance, holds a version of The Slogan with respect to narrative identity, a uniting sort of conception of identity (where various actions and experiences are united into the life of one person via a self-told narrative), but implicitly for her (as explicitly for DeGrazia) narrative identity actually presupposes numerical identity, insofar as hers is a theory about what makes experiences occurring at different times properly attributable to one and the same person or consciousness. So I will assume here that all these theorists think that moral responsibility presupposes numerical identity. In a later post I may show how moral responsibility doesn’t presuppose narrative-identity-sans-numerical-identity either.
To see what’s going on, then, consider an outline of an argument that’s representative of these theorists’ general approach:
1. One is morally responsible only for one’s own actions. (The Platitude)
2. Thus, an action is one’s own only if one is numerically identical with the performer of the action. (The Slogan)
3. X is numerically identical with Y iff X bears some specified numerical identity relation to Y.
4. Thus, an action is one’s own only if one bears some specified numerical identity relation to the performer of the action.
5. Thus, one is morally responsible only for those actions for which one bears some specified numerical identity relation to the performer of the action.
The general idea, then, is to apply one’s theory of numerical identity to the criterion of ownership of actions. So an advocate of the Biological Criterion (like DeGrazia) might wind up saying that one is responsible only for those actions for which one bears the relation of unique biological (animal) continuity to the original agent. Or an advocate of the Memory Criterion (like Locke) may say that one is morally responsible only for those actions for which one has a consciousness (memory) of the performance by the original agent. And the same goes for the advocate of the Psychological Criterion: one is morally responsible only for those actions for which one is uniquely psychologically continuous with the original agent.
The problem is that all these applications of specific criteria of personal identity succumb to powerful counterexamples. One obvious one is to Locke’s Memory Criterion: if Mel is caught for drunk driving and then yells anti-Semitic epithets at the arresting officer but fails to remember anything of the episode the next day, it seems clear he’s still morally responsible for his action, that the action was indeed his own. And one can think of counterexamples to the other criteria as well, examples where the action is the agent’s own action (and thus he’s responsible for it), even though the proffered criterion of identity doesn’t obtain.
But the most comprehensive counterexample comes from the fission case: if I were to split in two and each half re-grew its missing half, I couldn’t be identical with either survivor (they’d be exactly similar and so there’d be no non-arbitrary reason for me to be one or the other), and I couldn’t be identical with both (2≠1), so I must not be identical with either. Nevertheless, were I to perform some immoral action and then undergo fission, it seems our intuitions would be that both fission products are (at least to some degree) morally responsible for my actions. But how could my actions be theirs if they’re not identical with me?
Here is where someone like Sider steps in and suggests a four-dimensionalist ontology to save the general approach. There were, we can say, two space-time person-worms that were entirely spatially coincident for the stretch of time up until fission, at which point they split. So both fission products are morally responsible for their own actions insofar as they are both one and the same person as the original agent. Indeed, says Sider, its ability to resolve puzzles like fission is one motivation for adopting a four-dimensionalist ontology generally.
I think this move is unmotivated, however, simply because premise 1 (The Platitude) doesn’t entail premise 2 (The Slogan). All I’ll do here is offer an argument by analogy, and then I’ll let you hash it out. Here is a platitude about taxation: I can be legitimately taxed only on my own property, and never on someone else’s property. In one sense this is true, but in another sense it’s false. It is true that I cannot be taxed on your property if it is exclusively yours; it is false that I can’t be taxed on your property, however, if you and I share ownership of the property in question. We can accept, then, that a person can only be taxed on her own property, and that one person can’t be taxed on anyone else’s property, without having to accept that taxation presupposes exclusive property ownership.
Similarly, then, we can accept that a person can only be responsible for her own actions, and that one person can’t be responsible for anyone else’s actions, without having to accept that responsibility presupposes personal identity. The reason is that there are two senses in which I can’t be responsible for someone else’s actions. It is true that I can’t be responsible for actions that are exclusively yours; it is false that I can’t be responsible, however, for actions of which we share ownership. The fact that one owns an action doesn’t necessarily imply that one owns it exclusively, and that, therefore, there is a one-to-one identity relation between the current owner and the original agent. Instead, it just implies that one has a special ownership relation with the original agent’s action. But given that ownership isn’t necessarily tied to exclusivity—a single piece of property may have many owners, after all—one may easily deny The Slogan: The Platitude simply doesn’t entail that responsibility presupposes identity. Instead, it entails only the importantly different slogan that responsibility presupposes ownership. But if this is true, then the motivation to go four-dimensionalist is undercut. One can handle the fission case without violating The Platitude: both of my fission products can be responsible for my actions pre-fission, insofar as both share ownership of them. This renders the identity of the fission products irrelevant, at least with respect to responsibility, and so renders the difficulties associated with the various criteria of identity irrelevant as well. What we need now, of course, is an analysis of ownership of actions, but that’s for another day.