In addition to outlining the state of play, Essential Philosophy of Psychiatry presents a coherent and unified approach across the different debates, characterized by a rejection of reductionism and an emphasis on the ineliminability of uncodified skilled judgement.

The first part, Values, outlines the debate about whether diagnosis of mental illness is essentially value-laden and argues that the prospects for reducing illness or disease to plainly factual matters are poor. It also explains the important role of skilled contextual judgement, rather than a principles-based deduction, in ethical judgement.

The second part, Meanings, examines the central role of understanding and a shared first person perspective, both against attempts to reduce meaning to basic information-processing mechanisms and to explain away the difficulties of understanding psychopathology in recent models of delusion.

The third part, Facts, shows the importance of uncodified clinical judgements, both in assessing the validity of psychiatric taxonomy and in the application of Evidence Based Medicine. Despite advances in the codifaction of practice and operationalism of diagnosis, an element of judgement remains in the assessment both of what, at one level, is good evidence for diagnosis and treatment and what, at a higher level, is good evidence for the validity of classification overall.