An email: “I think you’re perhaps forgetting an important aspect of the argument from error, regarding the death penalty. The state deliberatly ends the life of those convicted of murder. In the case of speed limits and other governmental decisions that may result in greater deaths (as in the example of your article you referenced), those outcomes are in part dicatated by the actions of the individuals themselves, in addition to the general decision of the state. In the case of a wrongly convicted person who is executed, they are not killed because of anything specific they have done, but because of legal or procedural error, and ultimately the deliberate action of the state. (Worst of all, there is no meaningful recompense for them under the law for this error.)

“I point this out because it is the same distinction you so wisely made in a recent post comparing medical abortion to spontaneous abortion. The deliberateness of the action adds to the moral quality of the outcome. Ignorance of the innocence of the accused is no more an excuse that ignorance of the law would be. The innocent person dies in such a case because of the deliberate act of the state upon that specific person.”

My response: It is certainly true that in the hypothetical case of error we are discussing, the state would be directly killing an innocent person–in one sense of the word directly. But it would certainly not be deliberately acting to bring about the death of an innocent person.

It might be helpful to think about these issues in terms of war, where the possibility of error is much greater–you are almost guaranteed to have innocent civilian deaths–and where the state is acting directly in the same sense. I think the basic points I made apply to both cases. At some point, the number of innocent deaths from an otherwise just effort by the state–whether to conduct a war or (again assuming the death penalty is just when applied to guilty parties) to execute murderers–could rise to the level where that effort would have to be abandoned. But neither policy should be abandoned simply because there is some risk of such deaths as an undesired, though predictable, side-effect of the policy.