The perspectives on punishment mentioned so far have all been highly theoretical. Jurisprudence and the philosophical tradition are concerned with the ought of punishment - what ought to be the goals of punishment, what ought to be the values embodied in and upheld by the criminal law - and little will be encountered by way of discussion of the actual practices of punishment. The sociological perspective is concerned with the is of punish¬ment - what punishment really is for, what the true nature of modern penal systems is — again, this is description at a highly abstracted and theorized level. Such sociological description often claims to be revealing the 'deeper structures' of penal systems (Cohen 1984), and although actual policies and practices may be referred to, they are offered as examples, chosen to illustrate the analyst's general characterization of the penal systems under examination. In other words, in reading writers such as Melossi, Cohen or Foucault, one finds references to certain sorts of punishment, which they see as representative of the defining developments in modes of punishment of particular stages of social development; one does not find a full, descrip¬tive account of penal institutions, policies and practices.