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The One: Descartes, Plato, Kant
Alain Badiou’s 1983–1984 lecture series on “the One” is the earliest of his seminars that he has chosen to publish. It focuses on the philosophical concept of oneness in the works of Descartes, Plato, and Kant―a crucial foil for his signature metaphysical concept, the multiple. Badiou declares that there is no “One”: there is no fundamental unit of being; being is inherently multiple.
What is novel in Badiou’s view of multiplicity is his reliance on mathematics, and set theory in particular. A set is a collection of things―yet, as he observes, it often is taken to “count as one” operationally for the purposes of mathematical transformations. In this seminar, distinguishing between “the One” and “counting as one” emerges as essential to Badiou’s ontological project. His analysis of reflections on oneness in Descartes, Plato, and Kant prefigures core arguments of his defining work, Being and Event .
Showcasing the seeds of Badiou’s key ideas and later thought, The One features singular readings, breathtaking theorizations, and frequently astonishing offhand remarks.
What is novel in Badiou’s view of multiplicity is his reliance on mathematics, and set theory in particular. A set is a collection of things―yet, as he observes, it often is taken to “count as one” operationally for the purposes of mathematical transformations. In this seminar, distinguishing between “the One” and “counting as one” emerges as essential to Badiou’s ontological project. His analysis of reflections on oneness in Descartes, Plato, and Kant prefigures core arguments of his defining work, Being and Event .
Showcasing the seeds of Badiou’s key ideas and later thought, The One features singular readings, breathtaking theorizations, and frequently astonishing offhand remarks.
- GenresPhilosophy
288 pages, Hardcover
Published July 4, 2023
7 people are currently reading
39 people want to read
About the author
Alain Badiou
368 books1,015 followersAlain Badiou, Ph.D., born in Rabat, Morocco in 1937, holds the Rene Descartes Chair at the European Graduate School EGS. Alain Badiou was a student at the École Normale Supérieure in the 1950s. He taught at the University of Paris VIII (Vincennes-Saint Denis) from 1969 until 1999, when he returned to ENS as the Chair of the philosophy department. He continues to teach a popular seminar at the Collège International de Philosophie, on topics ranging from the great 'antiphilosophers' (Saint-Paul, Nietzsche, Wittgenstein, Lacan) to the major conceptual innovations of the twentieth century. Much of Badiou's life has been shaped by his dedication to the consequences of the May 1968 revolt in Paris. Long a leading member of Union des jeunesses communistes de France (marxistes-léninistes), he remains with Sylvain Lazarus and Natacha Michel at the center of L'Organisation Politique, a post-party organization concerned with direct popular intervention in a wide range of issues (including immigration, labor, and housing). He is the author of several successful novels and plays as well as more than a dozen philosophical works.
Trained as a mathematician, Alain Badiou is one of the most original French philosophers today. Influenced by Plato, Georg Wilhelm Friedrich Hegel, Jacques Lacan and Gilles Deleuze, he is an outspoken critic of both the analytic as well as the postmodern schools of thoughts. His philosophy seeks to expose and make sense of the potential of radical innovation (revolution, invention, transfiguration) in every situation.
Trained as a mathematician, Alain Badiou is one of the most original French philosophers today. Influenced by Plato, Georg Wilhelm Friedrich Hegel, Jacques Lacan and Gilles Deleuze, he is an outspoken critic of both the analytic as well as the postmodern schools of thoughts. His philosophy seeks to expose and make sense of the potential of radical innovation (revolution, invention, transfiguration) in every situation.
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Displaying 1 - 4 of 4 reviews
June 19, 2025
In these seminars, Badiou takes on what is arguably the hardest, yet most fundamental problem in the history of philosophy, namely, the problem of the one and the many. At multiple levels of scale, one invariant structure is repeated: reality always appears as a differentiated unity, a one-in-many structure. What makes this structure possible and intelligible? Answering this question is one of the basic tasks of philosophical reasoning, and Badiou revisits it, bringing fresh ammo to the seemingly insurmountable task.
He begins with Descartes' famous bifurcation of reality into two distinct causal realms, each with its own pattern of intelligibility: matter and mind. Here, Badiou provides an insightful analysis of the extent to which Descartes' subject, the subject who performs the Cogito to disclose its own being, both prefigures and falls short of Kant's transcendental subject. The parallel with Kant is important because, as Badiou points out, Descartes tries to identify, within the being of the self-conscious subject, the basic axioms or formal principles that can act as the foundation for the system of knowledge of nature. Of course, Descartes famously fails to find a purely subjective foundation for all knowledge, and Badiou has an excellent analysis of the reasons why Descartes had to fail.
He also provides one of the most breathtaking analyses of Descartes' proofs for the existence of God in his third Meditation that I have encountered so far. He shows how the subject's self-conscious being, insofar as the subject is merely a finite being, cannot suffice as the epistemological foundation for the new sciences of nature that Descartes sought. This, as Badiou points out, is why Descartes - unlike Kant - had to deploy the principle of sufficient reason to inquire into the source of the self-conscious subject, thereby arriving at God as the infinite, perfect ground that can act as the principle of unification bridging the gap between mind and nature. Badiou argues that Descartes' proof for God ultimately fails in large part because Descartes operated with an underdeveloped notion of the infinite that he thinks later mathematics (calculus) develops. As a result, Descartes can't rely on God to render intelligible how reality can be a one-in-many, a dual unity of subject and object. Descartes also failed to give absence a positive role in his picture of reality, hence why he distorted the nature of the subject by reifying it. Badiou here gestures to his own view that absence lies at the heart of the subject. He develops this idea in later works, which I am eager to explore.
Badiou then moves backwards from Descartes to explore the problem of the one and the many in Plato's Sophist and Parmenides dialogues. There, he argues that the subject is everywhere lurking behind the scenes in Plato, but that it is never explicitly theorized in his work. Badiou says that the subject is implicitly present in Plato's account of the mixing/combining function that discloses the one and the many in things, even though what makes possible that mixing/combining of elements is not explicitly thematized by him. For the record, I am not sure if Badiou is right to deny that Plato does have some kind of theory of the subject. After all, Plato says in several dialogues that there is a fundamental kinship between the soul and the forms, thus suggesting an essential bond between that which drives and internally structures our minds and agency, on the one hand, and that which drives and inwardly structures things in the outer world, on the other hand.
He then says that Kant explicitly thematize the transcendental subject that is implicitly presupposed by Plato in his discussion of the function of combining and mixing. According to Badiou, in Kant, combining and mixing are the work of the synthetic unity of apperception and of the transcendental subject which makes all synthesis possible. Badiou then gives a truly excellent analysis of how Kant's first critique sheds new light on the problem of the one and the many by introducing the transcendental subject as a purely subjective principle of unification and connectivity. He also has a nuanced understanding of Kant's transcendental idealism that defends it against the oft-repeated, straw-mannish charge that it amounts to a ridiculous form of projectivism and subjective idealism which sees the world as the product of mental construction and projection. Badiou interprets Kant in a way that elucidates the sense in which the latter can still preserve a lot of our common-sense notion that the real, as fundamentally other to subjectivity, cannot be collapsed to the synthesizing activity of the subject, even as it cannot justifiably and meaningfully be posited except insofar as it is essentially related to a possible subject.
Where I was starting to lose the thread was in the last two chapters of Badiou's discussion of the one and the many in Kant's second and third critiques. However, that is entirely a result of my own ignorance of those two critiques. I will revisit those chapters in the future, because Badiou seems to be making some truly mind-bending points about how Kant addresses the problem of the one and the many in the moral domain in his analysis of how freedom, in being autonomous, responds to the necessitating pull of the moral law. You get a kind of unity within the moral domain, and again, within the domain of an aesthetic of the sublime. But it remains unclear what unifies the three modes of intelligibility represented by each of the critiques: theoretical (1st Critique), moral (2nd Critique), and aesthetic (3rd Critique) intelligibility.
These seminars are not an easy read. They are not for the faint of heart. That said, it is worth keeping in mind that the seminars recorded here were, as Badiou mentions in the preface, initially delivered back in the 80s as evening lectures to laypeople. I guess enough laypeople in the 80s still loved philosophy enough to attend such lectures, on such difficult topics, after a busy day at work.
He begins with Descartes' famous bifurcation of reality into two distinct causal realms, each with its own pattern of intelligibility: matter and mind. Here, Badiou provides an insightful analysis of the extent to which Descartes' subject, the subject who performs the Cogito to disclose its own being, both prefigures and falls short of Kant's transcendental subject. The parallel with Kant is important because, as Badiou points out, Descartes tries to identify, within the being of the self-conscious subject, the basic axioms or formal principles that can act as the foundation for the system of knowledge of nature. Of course, Descartes famously fails to find a purely subjective foundation for all knowledge, and Badiou has an excellent analysis of the reasons why Descartes had to fail.
He also provides one of the most breathtaking analyses of Descartes' proofs for the existence of God in his third Meditation that I have encountered so far. He shows how the subject's self-conscious being, insofar as the subject is merely a finite being, cannot suffice as the epistemological foundation for the new sciences of nature that Descartes sought. This, as Badiou points out, is why Descartes - unlike Kant - had to deploy the principle of sufficient reason to inquire into the source of the self-conscious subject, thereby arriving at God as the infinite, perfect ground that can act as the principle of unification bridging the gap between mind and nature. Badiou argues that Descartes' proof for God ultimately fails in large part because Descartes operated with an underdeveloped notion of the infinite that he thinks later mathematics (calculus) develops. As a result, Descartes can't rely on God to render intelligible how reality can be a one-in-many, a dual unity of subject and object. Descartes also failed to give absence a positive role in his picture of reality, hence why he distorted the nature of the subject by reifying it. Badiou here gestures to his own view that absence lies at the heart of the subject. He develops this idea in later works, which I am eager to explore.
Badiou then moves backwards from Descartes to explore the problem of the one and the many in Plato's Sophist and Parmenides dialogues. There, he argues that the subject is everywhere lurking behind the scenes in Plato, but that it is never explicitly theorized in his work. Badiou says that the subject is implicitly present in Plato's account of the mixing/combining function that discloses the one and the many in things, even though what makes possible that mixing/combining of elements is not explicitly thematized by him. For the record, I am not sure if Badiou is right to deny that Plato does have some kind of theory of the subject. After all, Plato says in several dialogues that there is a fundamental kinship between the soul and the forms, thus suggesting an essential bond between that which drives and internally structures our minds and agency, on the one hand, and that which drives and inwardly structures things in the outer world, on the other hand.
He then says that Kant explicitly thematize the transcendental subject that is implicitly presupposed by Plato in his discussion of the function of combining and mixing. According to Badiou, in Kant, combining and mixing are the work of the synthetic unity of apperception and of the transcendental subject which makes all synthesis possible. Badiou then gives a truly excellent analysis of how Kant's first critique sheds new light on the problem of the one and the many by introducing the transcendental subject as a purely subjective principle of unification and connectivity. He also has a nuanced understanding of Kant's transcendental idealism that defends it against the oft-repeated, straw-mannish charge that it amounts to a ridiculous form of projectivism and subjective idealism which sees the world as the product of mental construction and projection. Badiou interprets Kant in a way that elucidates the sense in which the latter can still preserve a lot of our common-sense notion that the real, as fundamentally other to subjectivity, cannot be collapsed to the synthesizing activity of the subject, even as it cannot justifiably and meaningfully be posited except insofar as it is essentially related to a possible subject.
Where I was starting to lose the thread was in the last two chapters of Badiou's discussion of the one and the many in Kant's second and third critiques. However, that is entirely a result of my own ignorance of those two critiques. I will revisit those chapters in the future, because Badiou seems to be making some truly mind-bending points about how Kant addresses the problem of the one and the many in the moral domain in his analysis of how freedom, in being autonomous, responds to the necessitating pull of the moral law. You get a kind of unity within the moral domain, and again, within the domain of an aesthetic of the sublime. But it remains unclear what unifies the three modes of intelligibility represented by each of the critiques: theoretical (1st Critique), moral (2nd Critique), and aesthetic (3rd Critique) intelligibility.
These seminars are not an easy read. They are not for the faint of heart. That said, it is worth keeping in mind that the seminars recorded here were, as Badiou mentions in the preface, initially delivered back in the 80s as evening lectures to laypeople. I guess enough laypeople in the 80s still loved philosophy enough to attend such lectures, on such difficult topics, after a busy day at work.
March 19, 2024
The ease with which badiou can explain and discuss the intertextual thread of all three of these thinkers plus Heidegger and Lacan is absolutely incredible. The fact that he probably grossly simplified his thought as in order portray it in a way one can understand is mind boggling too. However, the amount of reading required prior to this text in order to truly understand it, plus the knowledge of set theory prevents this from being a very accessible work. Then again, anything dealing with Kant is difficult to make accessible. The reason I rated it lower than 4 is because it made me feel horrendous about my own ability to process philosophy.
December 3, 2024
This Badiou’s lecture series delivered in 1983-84 focuses in on three philosopher’s attempts to achieve a metaphysical concept of oneness as opposed to Badiou’s own concept of the multiple. This is far from easy and I found myself reading each lecture twice and spending a few days between each lecture thinking deeply about the material. Not easy, but all the time I was totally involved and thoroughly excited by the material. I just wish my university lectures had been something like this, like you were completely engaging with a philosopher, his ideas, and what he was trying to achieve .
November 27, 2025
The final section on Kant was the hardest in the book, but the final session was perhaps the most pleasant. I loved that you can see Badiou just prior to Being and Event, and in an incredibly clear (again, if difficult due to the matter at hand) tone. I feel this course is also essential for any philosopher, for engaging the topic of the One and the many should be of utmost importance for any contemporary materialist philosophy.
This is Badiou at some of his clearest.
This is Badiou at some of his clearest.
Displaying 1 - 4 of 4 reviews