The relationship between subject and object is one of the philosophical questions that are of direct relevance for understanding psychiatry as a clinical and scientific field. Characteristic examples from the history of psychiatry are analyzed, including the "romantic era", the clinical concepts in Germany at the turn of the century, and twentieth century theories associated with the linguistic turn in philosophy. The practical implications of these theoretical considerations are often underestimated; this is clarified by a critical look at operationalized diagnostic criteria in psychiatry and at one of the most influential modern epistemological theories, "Evolutionary epistemology."