In 1943, Philotheus Boehner, the distinguished Ockham scholar, published an article entitled “The Notitia Intuitiva of Non-existents according to William Ockham,” an article that has been extremely influential ever since.

This date can be regarded as a turning point in the history of the misunderstanding, in whole or in part, of Ockham’s theory of intuitive and abstractive cognition in this century. Before that date, eminent scholars2 had ascribed to Ockham the very doctrine of intuitive cognition of nonexistents he had rejected. In his article, Boehner proceeded to denounce their mistake. Ironically, however, in the very same article, he introduced a new mistake, now bearing on the whole of the theory. Unaware that he had misread a certain text, he ascribed to Ockham a theory of intuitive and abstractive cognition that neither he, nor anyone else as far as I know, ever subscribed to. Though this mistake was introduced in the literature more than fifty years ago, not only has it gone undetected, it has been repeated by most subsequent scholars who have written on the subject, all of whom have studied Boehner’s article. As a result, the mistake has become completely entrenched, and many scholarly discussionson Ockham’s epistemology have been based on the assumption that Ockham held a certain doctrine which, in fact, he never subscribed to, nor even conceived of.