Abstract
Roger Bacon’s De signis is a major contribution to the history of semantics. However, we know from the author's summary given in the Opus tertium that it has come down to us in an incomplete form. It belongs to the third part of Bacon’s Opus maius, devoted to the “knowledge of languages”. The three sections of the summary in the Opus tertium enable us to understand its organization. The first section presents various arguments in favor of knowledge of languages. The major part of the second section of the summary is related to the “power of words”, which was originally present in the section on mathematics and magic. The third section is not present is the edition of Opus maius III: it was devoted to the study of signs and signification, which corresponds to the De signis, and circulated independently, and to its application to theology, a section that has not been found. Just as the late Compendium studii theologiae, the De signis offers an original treatment of semantic and linguistic questions which are fully embedded in the sophisticated debates that took place in the faculties of arts in Paris and Oxford during the second half of the 13th century. Bacon’s linguistic analysis can be equally relevant for the study of the Bible and theology.