Abstract

Ockham’s razor is the idea that simpler hypotheses are to be preferred over more complex ones. In the context of medical diagnosis, this is taken to mean that when a patient has multiple symptoms, a single diagnosis should be sought that accounts for all the clinical features, rather than attributing a different diagnosis to each. This paper examines whether diagnostic parsimony can be justified by reference to probability theory. I argue that while attempts to offer universal justifications of diagnostic parsimony fail, a more constrained use of this diagnostic principle can be supported.