Thomas Aquinas on Mental Language

Many scholars noted that Thomas Aquinas was very elusive about mental language. Neither a full-fledged theory of mental language nor an accurate description of what happens in our mind when we speak or we listen to a given language can be found in his works. I fundamentally agree with this judgment; nonetheless I think that Aquinas had something important to say about mental language. My purpose in the article is to prove that Aquinas endorsed a version of the so-called “Language of Thought Hypothesis”. Influenced by Boethius, Aquinas seems to believe that our thought is primitively linguistic and provided with a natural grammar that is narrower than those of the different spoken and written languages. If our thought had no language-like articulation, Aquinas seems to argue, we could not be able to form and proficiently speak any language. I give arguments to prove, in particular, that Aquinas adopted a functional explanation of the acts of thought and a compositional description of their contents. On Aquinas’ texts, mental language can be articulated on two-levels, i.e., that of the natural concepts derived, by abstraction, from the extramental world and that of the logical operations that our mind can carry out on such concepts. Unlike Robert Pasnau, I think that Aquinas would be prepared to accept that the mere possession of concepts and mental operations is a necessary and sufficient condition to translate immediately our thought into a spoken and written language.