Four Ages of Understanding

The subtitle of this 1,019 page book is The First Postmodern Survey of Philosophy from Ancient Times to the Turn of the Twenty-First Century. Written by John Deely, a Thomist scholar who spent 15 years translating the seventeenth century Latin work, Tractatus de Signis by John Poinsot (also known as John of St. Thomas), the Four Ages of Understanding argues that the development of the concept of sign is the central thread in the history of philosophy.

The four ages of understanding in the title correspond for the most part with the dominant language(s) of philosophy. So far as is known, philosophy got its start as an independent line of thought in ancient Greece, where it was conceived as the study of nature and given the name “physics”. Greek philosphers in the first age of understanding didn’t dwell on the idea of sign and the Greek word that John Locke in the seventeenth century applied to the study of signs, σημειον or semiosis, was confined to natural signs, such as symptoms of disease or smoke from a fire. Deely traces Greek philosophy from Thales of Miletus (c. 625–545 BC) to Proclus (c. AD 410–485) and Pseudo-Dionysius (c. AD 455–535).

With the fall of the Roman empire and subsequent loss of Greek philosophy in the West until the thirteenth century revival of Aristotle’s works, the Latin age of understanding was left to develop its own philosophy of being, which in Deely’s hands stretches from Augustine’s (AD 354–430) introduction of the notion of sign through to John Poinsot’s (AD 1589–1644) grounding of the concept in the Tractatus de Signis. The work of Scholastics from Augustine to Poinsot is treated in great detail, consistent with Deely’s Thomism and his concern and obvious love for a scholarly tradition that recognizes the accomplishments of predecessors when advancing claims that expand the intellectual horizon. The more than 300 pages devoted to the Latin age will likely leave the modern reader a bit daunted, but with a firm appreciation for the subtlety, intricacy, and complexity of Scholastic thought.

During the modern age, which began with Descartes (AD 1596–1650) and extended through to Husserl (AD 1859–1938), Russell (AD 1872–1970), and Wittgenstein (AD 1889–1950), philosophy was developed in national languages and not in Latin. Deely’s contempt for modern philosophy runs deep; in his view, the modern philosophers who dominate the academy today have “become to philosophy’s future what the judges of Galileo were to the future of science.” Ouch! In Deely’s view, the moderns, in their justified reaction to the abuses of religious authority that blocked the way of inquiry, threw out the semiotic baby with the authoritarian bathwater. Their naive view that ideas represent objects in a dyadic relationship in the mind ignored the real triadic relation established between a representamen and an interpretant by a sign. Modern debates over whether the world exists outside the mind strike Deely as ghastly reminders of the damage done to the philosophical tradition when the concept of sign was lost or ignored in the modern age.

The future of philosophy belongs to post-modernism, which was introduced programmatically by John Locke (AD 1632–1704), but whose foundations were developed by the American logician Charles Sanders Peirce (AD 1839–1914). According to Deely, Peirce’s work was a clear advance on the work of the Latins.

The Latins, for the most part, got only as far as establishing the being proper to signs, the common factor or element which justifies the notion of sign in general in Augustine’s sense and removes it from every theoretical context of nominalism. But Peirce, in good medieval fashion, goes at once from this as established terrain to consider what immediately follows from it, namely the action proper to signs … Recall what Peirce said about the sign in its proper character as a genuine mediation: anything is related to a second thing, its Object, in respect to a quality, its Ground, in such a way as to bring a third thing, its Interpretant, into relation to the same Object, and that in such a way as to bring a fourth into relation to that Object in the same form, ad infinitum.

When the action proper to signs is combined with Peirce’s claim that all thought is in signs, then the infinite semiosis described above becomes a good description of the activity that generates an intellectual tradition, such as the one Deely uncovers so wonderfully in Four Ages of Understanding.