The possibility test for intentions

This test for whether one is intending some effect E of an action is often employed (e.g., by Germain Grisez) in the Double Effect literature:

1. If it is logically possible for an action with an intention J to be fully successful even though E does not happen, then E is not included in J.

Claim (1) follows in standard modal logic (with no need for anything fancy like S5) from:

2. If an intention J includes E, then the inclusion of E is an essential property of J.

3. Necessarily, if an action is done with an intention that includes E and E does not occur, then the action is not fully successful.

For suppose that E is included in J. Then in every possible world where an action is done with J, the action is done with an intention that includes E by (2)) and so in every possible world where an action is done with J, the action is not fully successful if E does not occur, by (3). Hence, there is no possible world where an action is done with J and is fully successful even though E does not happen. Thus, we have (1).

At the same time, (1) sounds awfully strong. Even if the possible world where the action is successful despite the lack of E requires a miracle, E is not included in J. For instance, suppose God is able to keep the soul of a human being bound to a single atom. That means that someone whose intention was to blow the man blocking the mouth of the cave literally to single atoms was not intending death, since there is a possible world where the person’s soul remains bound to a single atom, and in that world the action is clearly successful.

To deny (1), one needs to deny (2) or (3). I think the best route to denying (2) is a strong dose of semantic externalism: the content of an intention is dependent in part on things outside the individual. Perhaps on Earth the very same intention may be an intention to drink water, while on Twin-Earth the very same intention may be an intention to drink XYZ. I am sceptical of this: it seems to me that the best way to understand the water-XYZ issue is that intentions are partly grounded in facts outside the individual, and so it is a different intention on Twin-Earth than on Earth, even if it is partly grounded in the same facts in the individual.

But even if one is impressed by the water-XYZ issue, it seems one should be willing to accept the following variant on 2:

4. If an intention J includes E and occurs at t, then in any possible world that exactly matches the actual world up to an including t the intention J includes E at t.

The argument for (1) can now be modified to yield an argument for:

5. If an action with an intention J occurs at t, and if there is a possible world that matches the actual world up to and including t and where the action with J is fully successful but where E does not happen, then E is not included in J.

And if one’s motivation for denying (1) is to avoid the conclusion that intending to blow the man in the mouth of the cave to single atoms does not include intending death, then (5) is just as bad. For God could miraculously keep the soul bound to a single atom without anything being any different up to and including the time of the action.

If we don’t want (1), we won’t want (5), either.

So a better bet is to deny (3). A start towards a denial of (3) would be to talk of something like “stretch goals”. It seems that an action may have a stretch goal and yet be successful even if that stretch goal is unachieved. However, the stretch goal is surely intended.

I am not sure. If the stretch goal is intended, then it seems that the right thing to say is that the action is successful but not fully successful if the stretch goal is not met.

In any case, we might grant the claim about stretch goals, and introduce the concept of an intention being perfectly satisfied, which includes the satisfaction of all stretch goals, and then replace “fully successful” with “perfectly successful” in (1) and (5). And I think this will still generate the result about blowing the fat man to atoms, because the death of the fat man—the separation of soul from body—is not a stretch goal either. (If anything, one might imagine that his survival is a stretch goal.)

All this makes me want to say that (3) really is true, and we cannot avoid the conclusion that it is possible to intend to blow the man in the mouth of the cave to single atoms without intending to kill him. But I am now inclined to think that an intention to kill is not a necessary condition for murder, and so the action could still be a murder.