Unfortunately I don’t have the time right now to discuss this in any more depth, but check out this interesting new article by Richard Dawkins:

Shouldn’t the decision to execute somebody, or imprison them for life, be taken seriously enough to warrant a repeat of the experiment? I’m not talking about a retrial. Nor an appeal, although that of course is desirable, and happens when there is some disputed point of law or new evidence. But suppose every trial had two juries, sitting in the same courtroom but forbidden to talk to each other. Who will bet that they would always reach the same verdict? Does anybody think a second jury is likely to have acquitted O J Simpson?