  These two interpretations are set out in section 2. Explanation is discussed in section 3. The strong interpretation naturally suggests that psychiatry should embrace the practices of medical explanation. If disease is a pathological process in bodily systems, then there must be a way of understanding how such processes occur in the brain, and how they explain the clinically observable facts about mental illness. But it seems that the logic of the medical model does not force us to privilege any one level of explanation—notably, it does not commit us to explanations restricted to the resources of molecular biology. Psychiatry, then, is a multi-level science. But we often know very little about the mental illnesses that psychiatrists study, and much explanation in psychiatry involves case studies or narrative accounts that cite the characteristics of a disorder, rather than underlying systems. Theorists disagree over whether these should be seen as different kinds of explanation, or as rudimentary forms of a full causal explanation. Section 3 also discusses the difficulties raised by cross-cultural issues. Section 4 discusses some recent approaches to mental illness that are broadly within the medical model but dissent from the mainstream.