What does it mean to construct scientific knowledge about mental health? What commitments are involved? What evidence must be gathered, and how should it be handled? This contribution presents some reflections from the philosophy of science aimed at clarifying possible conception of “mental disorder” and “scientific objectivity”, and at highlighting the roles that values – both epistemic and non-epistemic – can play in the development of theories and models. By discussing possible conceptual and methodological intersections and interactions with the philosophy of science, the goal is to bring out a picture of the mental health disciplines as a form of knowledge that is at once fallible and reliable.