Much research in the philosophy of psychiatry has been devoted to the characterization of the normal and the pathological. In this article, we identify and deconstruct two postulates that have held sway in the philosophy of psychiatry. The first postulate concerns the belief that clinicians would benefit from conceiving of psychiatric disorders as stable entities with clear boundaries. By relying on a symptom-based approach, we support a conception of psychiatric disorders whose symptoms are the products of many activated mechanisms in (...) mutual interactions. The second postulate concerns the way in which the philosophy of psychiatry has approached the question of harm. We posit that clinicians perceive harms primarily through networks of clinical manifestations. The identification and deconstruction of these two postulates leads us to propose a practical definition of a psychiatric disorder that is useful for the clinician, while adopting a principle of prudential conservatism that does not exclude other theoretical definitions of psychiatric disorder that are useful as an epistemic hub. Thus, we propose the following definition of a psychiatric disorder that is relevant to clinical practice: “a set of clinical manifestations belonging to the prototypical central core of psychiatry, organized in a causal network, involving at least one harm, and whose set of harms exceeds the traditional threshold of significance for a given psychiatric disorder, directly related to an activated mechanism. Such a network composed of clinical manifestations is frozen in a state that is unable to allow the deactivation of these manifestations spontaneously without a therapeutic intervention”. (shrink)