As they say, “Better than n guilty men go free than one innocent man be punished.” See also 146 U. Pa. L. Rev. 173 (1997). But how do you figure out what value of n you think the legal system should adopt? Easy — just do this set of hypotheticals:

1. Suppose you have a set of identical twins, and you know one of them committed a crime, but you don’t know which one. Each has an equally persuasive alibi. Do you convict them both, or do you let them both go? If you let them both go, then you believe n is at least 1.

2. Suppose you have a set of identical triplets, and you know two of them committed a crime together, but you don’t know which two. Each has an equally persuasive alibi. Do you convict all three, or do you let them all go? If you let them all go, then you believe n is at least 2.

3. Suppose you have a set of identical quadruplets, and you know three of them committed a crime together….

You see how this goes. Well, it turns out this isn’t just hypotheticals anymore.