What is Logic About?

Another lively debate of the late thirteenth and early fourteenth century that played a significant role in the development of the theory of mental language was the discussion over the object of logic as a science, and whether it is primarily concerned with thought or language. It was held by various philosophers that the structure of mental language is what logic deals with. But they did not all agree on what mental language was: some said (as Ockham would) that it is composed of concepts, others (such as Walter Burley) that it is composed of real external things, and others again (such as Richard Campsall) that it is composed of the mental representations of external words. This chapter reviews these various positions and the arguments which supported them.

Triple is the Word

This chapter focuses on the use of the idea of mental discourse in Latin medieval philosophy from the late `eleventh to the mid-thirteenth century. A crucial passage from Anselm of Canterbury is first examined in some details. It is then shown how the idea occurred within a surprising variety of threefold distinctions in quite a number of authors. The notion that the object of grammar as a science is some sort of ‘language in the mind’ (sermo in mente) is also discussed. What comes out is that the Ancient philosophical tradition of the logos endiathetosand the Augustinian tradition of the verbum in mente are now being brought together in various ways and that an important Augustinian distinction between internal discourse properly speaking and the mental representation of spoken words and sentences has become commonly accepted.

Verbum in Corde

Early Christian theologians such as Justin Martyr and Theophilus of Antioch borrowed the philosophical idea of internal discourse as a useful wordly comparison for understanding the engendering of the Son by the Father in the divine Trinity. Occurring first in apologetic and polemical writings, this recourse to philosophy became controversial among theologians themselves. Augustine, however, systematically developed the concept of ‘mental word’ in the context of Trinitarian theology and promoted the notion that human thought is a kind of internal speech underlying natural languages and prior to them.

Plato and Aristotle

The most important relevant passages from Plato and Aristotle are scrutinized. Plato’s focus is on the soul’s dialogue with itself, while Aristotle sees internal discourse as the locus of logical relations. The problem of the compositional structure of thought is shown to arise from Aristotle’s work, without however being addressed by him.

Reactions

This chapter examines how Ockham’s theory of mental language eventually won the field among his immediate successors. It first reviews a controversy among Dominican authors on whether there really is a mental language composed of concepts, and then another series of discussions over what syntactic structure exactly such a mental language could have. And it finally focuses on the idea of mental language in John Buridan, arguably the most important philosopher of the fourteenth century after Ockham.

Act Versus Idol

It is only toward the mid-thirteenth century that mental discourse began to be the object of explicit and precise philosophical controversies. Thomas Aquinas played a crucial role in this by progressively developing an original way of harmonizing Augustine’s idea of mental word with Aristotle’s theory of abstraction. Aquinas’s main innovation was to distinguish between the ‘intelligible species’ stocked in the mind as a result of the abstraction process and the concept or mental word produced by the mind when it is actively thinking about something. This doctrine soon became controversial as it was thought by many to introduce a superfluous and harmful veil of purely ideal objects between the mind and the external things. The Thomistic synthesis is explained in this chapter as well as the philosophical criticisms it was subjected to in the late thirteenth century.

Introduction

The general idea of mental language is introduced. The resemblance between Jerry Fodor and William of Ockham’s ideas is stressed. The goal and the methodology of the research that led to this book is stated.

Conclusion

The Conclusion briefly summarizes the book and provides a list of thirty-six different appellations for mental language in Ancient and medieval philosophy (e.g. logos endiathetos, verbum in corde, verbum intellectuale, oratio mentalis, etc.). It then suggests a number of contemporary philosophical discussions for which this historical enquiry could be relevant, over the compositional structure of thought, for example, the ontological status of intellectual representation, or the connection between thought and language.

Oratio Mentalis

From the third to the seventh centuries, Neoplatonist philosophers such as Porphyry and Ammonius used the idea of internal discourse in their commentaries to Aristotle. Boethius acted as a transmitter to the Latin world in this regard, especially by quoting an earlier threefold distinction between spoken, written, and mental discourses. The question as to whether he endowed the latter with a grammatical structure is discussed in some details—and answered negatively. The Greek notion of internal discourse is also shown to occur in some influential Islamic thinkers, especially al-Fârâbi and Avicenna.

Postscript to the English-Language Edition (2014)

Especially written for the English version, this Postscript discusses a number of recently published contributions on the history of mental language in connection with the claims made in the present book. Those are divided into five groups according to whether they have to do with (1) Ancient and Patristic sources, (2) Augustine and Boethius, (3) Abelard and the twelfth century, (4) Aquinas and the thirteenth century, and (5) Ockham and the late medieval period. It is shown that quite an amount of new material is now to be added to the picture, but that nothing of importance needs to be withdrawn.