George Engel's (1913-1999) biopsychosocial model, one of the most significant proposals for the renewal of medicine in the latter half of the 20th century, has been understood primarily as a multi-factorial approach to the etiology of disease and as a call to re-humanize clinical practice. This common reading of Engel's model misses the central aspect of his proposal, that the biopsychosocial model is an epistemology for clinical work. By stating the simple fact that the clinician is not dealing directly with a body, but first, and inevitably, with a person, Engel challenged the epistemology implicit in the classical clinical method-a method predicated on the possibility of direct access to the body. Framed in epistemological terms, the issue at stake is not the need to complement medical science with humane virtues, but rather to acknowledge that the object of clinical practice is not the body but the patient.