## Thursday, November 9, 2017

### Proportionality in Double Effect is not a simple comparison

It is tempting to make the final “proportionality” condition of the Principle of Double Effect say that the overall consequences of the action are good or neutral, perhaps after screening off any consequences that come through evil (cf. the discussion here).

But “good or neutral” is not a necessary condition for permissibility. Alice is on a bridge above Bob, and sees an active grenade roll towards Bob. If she does nothing, Alice will be shielded by the bridge from the explosion. But instead she leaps off the bridge and covers the grenade with her body, saving Bob’s life at the cost of her own.

If “good or neutral” consequences are required for permissibility, then to evaluate the permissibility of Alice’s action it seems we would need to evaluate whether Alice’s death is a worse thing than Bob’s. Suppose Alice owns three goldfish while Bob owns two goldfish, and in either case the goldfish will be less well cared for by the heirs (and to the same degree). Then Alice’s death is mildly worse than Bob’s death, other things being equal. But it would be absurd to say that Alice acted wrongly in jumping on the grenade because of the impact of this act on her goldfish.

Thus, the proportionality condition in PDE needs to be able to tolerate some differences in the size of the evils, even when these differences disfavor the course of action that is being taken. In other words, although the consequences of jumping on the grenade are slightly worse than those of not doing so, because of the impact on the goldfish, the bad consequences of jumping are not disproportionate to the bad consequences of not jumping.

On the other hand, if it was Bob’s goldfish bowl, rather than Bob, that was near the grenade, the consequences of jumping would be disproportionate to the consequences of not jumping, since Alice’s death is disproportionately bad as compared to the death of Bob’s goldfish.

Objection: The initial case where Alice jumps to save Bob’s life fails to take into account the fact that Alice’s act of self-sacrifice adds great value to the consequences of jumping, because it is a heroic act of self-sacrifice. This added increment of value outweighs the loss to Alice’s extra goldfish, and so I was incorrect to judge that the consequences are mildly negative.

Response: First, it seems to be circular to count the value of the act itself when evaluating the act’s permissibility, since the act itself only has positive value if it is permissible. And anyway one can tweak the case to avoid this difficulty. Suppose that it is known that if Alice does not jump on the grenade, Carl who is standing beside her will. And Carl only owns one goldfish. Then whether Alice jumps or not, the world includes a heroic act. And it is better that Carl jump than that Alice, other things being equal, as Carl only has one goldfish depending on him. But it is absurd that Alice is forbidden from jumping in order that a man with fewer goldfish might do it in her place.

Question: How much of a difference in value can proportionality tolerate?

Response: I don’t know. And I suspect that this is one of those parameters in ethics that needs explaining.