 We should not assume, however, that there is only one question of justification, which can receive just one answer. As Hart famously pointed out (Hart 1968: 1–27), we must distinguish at least three justificatory issues. First, what compelling reason is there to create and maintain a system of punishment: what good can it achieve, what duty can it fulfil, what moral demand can it satisfy? (Hart termed this the question of punishment's ‘general justifying aim’, although the term may be misleading in that talk of ‘aims’ may seem to privilege a consequentialist answer to the question, whereas the compelling reason could be a nonconsequentialist one.) Second, who may properly be punished: what principles or aims should determine the allocations of punishments to individuals? Third, how should the appropriate amount of punishment be determined: how should sentencers go about deciding what sentence to impose? (One dimension of this third question concerns the amount or severity of punishment; another, which is insufficiently discussed by philosophers, concerns the concrete modes of punishment that should be available, in general or for particular crimes.) It might of course turn out that answers to all these questions will flow from a single theoretical foundation — for instance, from a unitary consequentialist principle specifying the good that punishment should achieve, or from some version of the retributivist principle that the sole proper aim of punishment is to impose on the guilty the punitive burdens they deserve. But matters might not be as simple as that: we might find that quite different and conflicting values are relevant to different issues about punishment, and that any complete normative account of punishment will have to find a place for these values and offer guidance in how to resolve tensions among them when they conflict (see s. 6).