Home » Semiotics: The Tractatus de Signis of John Poinsot

What is a sign? It is a deceptively difficult question—deceptive because we think we know when we have never bothered truly to ask the question. We believe that we see and hear signs everywhere: guiding our use of streets, telling us where to exit, the location of the bathroom, what dangers might lie ahead, and so on. But in truth, though we experience signification in these instances, the things we identify as the “signs”—the on the street corner, the glowing plastic “EXIT” over a fire door, the nondescript white silhouette of a representatively feminine shape over one door, the print of a large clawed mammal in soft dirt—are only a part of the signs that we experience. The truth hides in a reality far more complex and far more interesting. Discovery and understanding of this hidden reality impacts our understanding of the whole universe, and of ourselves not least of all.

We name this a seminar in “semiotics”, and so one might expect that it concerns thinkers and issues raised no earlier than the late 19th or early 20th centuries, at which time Charles Sanders Peirce (10 September 1839—1914 April 19) retrieved the term from its neglected proposal in John Locke’s Essay Concerning Human Understanding. But—while certainly we will be concerned with many of the issues that preoccupied Peirce and his successors—we find their genesis not in the twilight of modernity, but the twilight instead of the Latin Age. For Peirce was inspired in much of his thinking by the Conimbricenses, a 16th-17th century semi-anonymous group of Jesuit scholars who wrote extensively and profoundly on signs. These same Conimbricenses were, moreover, the teachers of João Poinsot, variously known also as Juan de S. Thoma, Joannes a Sancto Thoma, John of St. Thomas, or, in our usage here, John Poinsot (9 July 1589—1644 June 15).

Poinsot, who took the religious name Joannes a Sancto Thoma upon entering the Dominican Order in 1610 to signify his fidelity to the great saint’s thought, died just six years before René Descartes (31 March 1596–1650 February 11) and yet, despite a much greater profundity of thought and insight, has remained relatively unknown (at least when compared to his French counterpart). Indeed, where Descartes began in earnest the Modern Age of philosophy, with its characteristic Way of Ideas, Poinsot brought to a close the Latin Age. Their relative fame and obscurity to history follow from complex causes. One of these, no doubt, is that while Descartes wrote short and accessible texts, Poinsot crafted both a Cursus Philosophicus and an (incomplete) Cursus Theologicus—each many thousands of pages.

Within this Cursus Philosophicus we find a textually-dispersed but nevertheless conceptually-united Tractatus de Signis, a Treatise on Signs [required]. This treatise has been extracted, arranged, translated, and editorialized in an edition by John Deely (26 April 1942—2017 January 7), first published in 1985 and again in 2013. A careful examination of this text reveals that, while Poinsot may have been the “evening star” of the Latin Age, he proves also the “morning star” of the new, genuinely post-modern era, the Age of Relation. In this seminar, we will study this Tractatus de Signis with close attention. Access to the seminar begins on 18 March 2023.


Discussion Sessions

2:15pm ET

(World times)
Study Topics &

(required in bold)
Copy of the Tractatus de Signis is required. Available from St. Augustine’s Press or other booksellers (1st edition acceptable).
18 March—April 8Preparatory Phase:
All participants are expected to read widely from a selection of articles and texts—including reading required texts in advance—while joining in communal textual discussion.

No discussions are scheduled during this phase, but it is pivotal for entering correctly into the active discussion phase (15 April—June 10).
Week 1: Preliminaries: Entry into the Tractatus
Lecture: An Abbreviated History of Semiotics
» Poinsot 1632: Tractatus de Signis (TDS) 4–39.
» Deely 1994: “A Morning and Evening Star”
» Deely 2009: Augustine & Poinsot, 3–59.
» Kemple 2022: “Augustine: Instituting the Given Sign” and “Aquinas: The Metaphysics behind Semiosis”.
Week 2: Cognition-Dependent Being
Lecture: Entia Rationis and the Constitutive Acts of the Mind
» Poinsot 1632: TDS, 40–76.
» Maritain 1959: Degrees of Knowledge, 118–44.
» Doyle 1994: “Poinsot on the Knowability of Beings of Reason”.
Week 3: Relational Being
Lecture: The Nature and Kinds of Relation
» Poinsot 1632: TDS, 78–112.
» Deely 1985: “Editorial Afterword” in TDS, 472–89.
Week 4: Sign-Relations
Lecture: The Being Proper to Signs
» Poinsot 1632: TDS, 114–52.
» Deely 1990: “Signs: The Medium of Semiosis” in Basics of Semiotics.
» Kemple 2022: “Poinsot: The Essence of the Sign”.

Week 5: Triadic Elements of the Sign-Relation
Lecture: Cognitive Powers and Objects
» Poinsot 1632: TDS, 153–92.
» Deely 2009: Purely Objective Reality, 14–37.
Week 6: The Causality and Extension of Signs
Lecture: The Degrees of Specifying Causality
» Poinsot 1632: TDS, 193–219.
» Deely 1994: New Beginnings, 151–82.
Week 7: Division of Signs, Part I
Lecture: Toward an Understanding of Concepts
» Poinsot 1632: TDS, 220–61.
» Beuchot 1994: “Intentionality in John Poinsot”.
Week 8: Division of Signs, Part II
Lecture: Toward an Understanding of Language
» Poinsot 1632: TDS, 262–83.
» Maritain 1957: “Language and the Theory of Sign”.
10 June—July 2Writing Phase:
All participants in the seminar are not only encouraged but expected to submit an essay of no less than 3000 words pertaining to the Tractatus de Signis of Poinsot.

The essay may be evaluated for publication in Reality.


Lyceum Institute seminar costs are structured on a principle of financial subsidiarity. There are three payment levels, priced according to likely levels of income. If you wish to take a seminar but cannot afford the suggested rate, it is acceptable to sign up at a less-expensive level. The idea is: pay what you can. Those who can pay more, should, so that those who cannot pay as much, need not. Lyceum Institute members receive a further discount (see here for details).

This is an advanced seminar, tantamount to a graduate course in difficulty and intensity. Students should be familiar with the Scholastic and especially Thomistic traditions, or at the very least, with the semiotic work of John Deely.

[2023 Spring] Semiotics: Poinsot – Public Participant

Recommended for those who are currently students or with part-time employment.


[2023 Spring] Semiotics: Poinsot – Public Patron

Recommended for those in professions that do not pay as well as they ought and for whom continued education is especially important (including professors and clergy).


[2023 Spring] Semiotics: Poinsot – Public Benefactor

Recommended for those with fulltime employment in well-paying professions and sufficient resources to provide a little more.


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