Abstract It is a fundamental assumption in nursing theory that it is important for nurses to understand how patients think about themselves and the contexts they are in. According to modern theories of hermeneutics, a nurse and a patient must share the same concepts in order to communicate beliefs with the same content. But nurses and patients seldom understand medical concepts in exactly the same way, so how can this communicative aim be achieved in interaction involving medical concepts? The article uses a theory of concepts from recent cognitive science and philosophy of mind to argue that nurses and patients can share medical concepts despite the diversity of understanding. According to this theory, two persons who understand medical language in different ways will nevertheless possess the same medical concepts if they agree about the normative standards for the applications of the concepts. This entails that nurses and patients normally share medical concepts even though patients’ conceptions of disease and illness are formed in idiosyncratic ways by their social and cultural contexts. Several practical implications of this argument are discussed and linked to case studies. One especially important point is that nurses should seek to make patients feel comfortable with deferring to a medical understanding. In many cases, an adequate understanding of patients presupposes that nurses manage to do this. Another implication is that deference-willingness to normative meaning is not equivalent to the actual application of concepts. Deference-willingness should rather be thought of as a pre-communicative attitude that it is possible for patients who are not fully able to communicate to possess. What is important is that nurses and patients have the intention of conforming to the same meaning.