Duff RA (2020) Criminal Law. In: Tasioulas J (ed.) Cambridge Companion to the Philosophy of Law. Cambridge Companions to Law. Cambridge: Cambridge University Press, pp. 313-330. https://www.cambridge.org/gb/academic/subjects/law/jurisprudence/cambridge-companion-philosophy-law?format=HB
First paragraph: Philosophical (as distinct from sociological or historical) theories of criminal law display both analytical and normative dimensions. Analytically, they investigate the defining features of criminal law, as a distinctive kind of law. Normatively, they examine the proper structure and aims of criminal law: what principles should govern it? Towards what goals should it be oriented? Why should we maintain a system of criminal law?