H. L. A. Hart's new book of essays (Punishment and Responsibility, Oxford 1968) rejects any theory of the classic retributive type for justifying legal punishment. Hart denies that useless punishments can be justified even of fully guilty men; he rejects as the justifying aim of punishment the hope of crowning wickedness with the suffering it deserves; he denies that great guilt could justify a more severe punishment than utility-considerations would call for. We will be concerned here with only one of his arguments supporting this rejection: the objection that mere human judges cannot measure wickedness accurately enough to see that each degree of wickedness gets the appropriate amount of suffering. And of course modern fashions of determinist thinking have brought home to us even more vividly the absurdity of trying to measure wickedness, since determinism makes us wonder if we know how much any offender could have helped doing what he did.