Ockham and Chatton on the Origin of Logical Concepts

In the fourteenth century, many philosophers discuss the hypothesis of the existence of mental language. This kind of language is commonly described as expressing the logical structure of our conventional languages. While medieval logicians agree to a certain extent on the natural origin of the concepts that are the constitutive elements (subject and predicate) of mental language, they disagree on the origin of so-called ‘syncategorematic concepts’, that is, the concepts corresponding to the logical operators (e.g. copula, connectives, quantifiers, modalities, and so on). If, for example, William of Ockham seems uncertain about the natural or conventional origin of syncategorematic concepts, and his position seems to evolve across time, his confrère Walter Chatton convincingly defends their natural origin. Stating that our logical concepts are innate or instead that they result from the internalization of a conventional language paves the way to different treatments of mental language. In this paper, we shall compare Ockham’s and Chatton’s views of logical concepts.