In addiction, apparently causally significant phenomena occur at a huge number of levels; addiction is affected by biomedical, neurological, pharmacological, clinical, social, and politico-legal factors, among many others. In such a complex, multifaceted field of inquiry, it seems very unlikely that all the many layers of explanation will prove amenable to any simple or straightforward, reductive analysis; if we are to unify the many different sciences of addiction while respecting their causal autonomy, then, what we are likely to need is an integrative framework. In this paper, we propose the theory of "Externalist" or "4E"-for extended, embodied, embedded, and enactivecognition, which focuses on the empirical and conceptual centrality of the wider extra-neural environment to cognitive and mental processes, as a candidate for such a framework. We begin in Section 2 by outlining how such a perspective might apply to psychiatry more generally, before turning to some of the ways it can illuminate addiction in particular: Section 3 points to a way of dissolving the classic dichotomy between the "choice model" and "disease model" in the addiction literature; Section 4 shows how 4E concepts can clarify the interplay between the addict's brain and her environment; and Section 5 considers how these insights help to explain the success of some recovery strategies, and may help to inform the development of new ones.