RésuméEn expliquant la relation entre hypothèses et images dans l'analogie de la ligne du livre Vl de laRépubliquede Platon, je m'attarde d'abordsur l'élucidation platonicienne de la nature des mathématiques telle que la conçoit le mathématicien lui-même. Je poursuis avec une critique des interprétations traditionnelles de cette relation, qui partent de l'assomption douteuse que les mathématiques s'occupent des Formes platoniciennes. Pour formuler mon point de vue sur cette relation, j'exploite la notion de «structure». Je montre comment les «hypothèses» comme principes de (...) preuve peuvent déterminer les structures des «images» par lesquelles les structures intelligibles correspondantes des objets mathématiques en viennent à être connues. (shrink)

RésuméEn expliquant la relation entre hypothèses et images dans l'analogie de la ligne du livre Vl de laRépubliquede Platon, je m'attarde d'abordsur l'élucidation platonicienne de la nature des mathématiques telle que la conçoit le mathématicien lui-même. Je poursuis avec une critique des interprétations traditionnelles de cette relation, qui partent de l'assomption douteuse que les mathématiques s'occupent des Formes platoniciennes. Pour formuler mon point de vue sur cette relation, j'exploite la notion de «structure». Je montre comment les «hypothèses» comme principes de (...) preuve peuvent déterminer les structures des «images» par lesquelles les structures intelligibles correspondantes des objets mathématiques en viennent à être connues. (shrink)

In this paper, I argue that the two versions of divided line create problems that cannot be solved — with or without the hypothesis that the objects belonging to the level of διάνοια on the divided line are intermediates. I also argue that the discussion of arithmetic and calculation does not fit Aristotle’s attribution of intermediates to Plato and provides no support for the claim that Plato had such intermediates in mind when he talked about διάνοια in the Republic. The (...) upshot of my argument is negative: even if Aristotle’s report about Plato and intermediates is correct, there is no evidence for such objects provided in the passages I review from the Republic. If they are to be found in Plato, it will have to be elsewhere that they are found. (shrink)

This paper takes a detailed look at the Republic’s Divided Line analogy and considers how we should respond to its most contentious implication: that pistis and dianoia have the same degree of ‘clarity’ (σαφήνεια). It argues that we must take this implication at face value and that doing so allows us to better understand both the analogy and the nature of dianoia.

In this paper, I consider Plato's persistent and ubiquitous uses of imagery in the Republic, and compare his uses of images with what he says about the uses (and abuses) of imagery in the curricula he proposes for the kallipolis. I show how the dialogue itself might be suited to different levels of the proposed curricula--especially for those at the level of thought (dianoia)--but conclude that the dialogue was not intended to fit into the educational schemes of the 'kallipolis', but (...) was intended, instead, as educational for would-be lawgivers. (shrink)

The purpose of this paper is to reassess some mathematical examples in Plato’s dialogues which at a first glance may appear to be nothing more than trivial puzzles. In order to provide the necessary background for this analysis, I shall begin by sketching a brief overview of Plato’s mathematical passages and discuss the criteria for aptly selecting them. Second, I shall explain what I mean by ‘mathematical examples,’ and reflect on their function in light of the discussion on παραδείγματα outlined (...) in theSophistand theStatesman. Against this framework, I shall move to a close examination of specific examples drawn from theTheaetetus(154c–55d), theRepublic(523c–24d), and thePhaedo(96d–97b, 100e–101d). By placing these examples in the broader context of pre-Euclidean mathematics, I shall show that their mathematical content is often less elementary than might appear at first sight. Moreover, by placing emphasis on the specific philosophical concerns that motivated their introduction, I shall argue that the examples are not merely nonsensical jokes. Even if their illustrative purpose is not always immediately clear, and even if they can sound playful and bizarre, they in fact fulfil an important function: by virtue of their power to generate wonder or confusion, they serve as exercises and act as a trigger with respect to the difficult philosophical issues they are intended to clarify. (shrink)

In this paper, I examine the problem of the so-called Mathematical Objects within the context of the Divided Line. I argue that Plato believes that there are such objects but their distinctness and the mode of cognition relative to them can only be understood in relation to the superordinate, unhypothetical first principle of all, the Idea of the Good. The objects of mathematics or διάνοια are, unlike the objects of intellection or νόησις, cognized independently of the Good.

El propósito de este ensayo es presentar una interpretación deflacionaria de la línea dividida en República VI-VII. Argumento que una parte importante de las dificultades existentes entre la διάνοια y la νόησις radica en el hecho de que se leen las diferentes secciones de la línea dividida como si fueran compartimientos cerrados. Mi afirmación es que uno de los problemas cruciales y de difícil solución es cómo entender que un alma que opere según la νόησις pueda llevar a cabo sus (...) actividades cognitivas prescindiendo completamente de cualquier ingrediente sensible, toda vez que el alma que procede “noéticamente” está en un cuerpo. Para intentar explicar este importante detalle utilizo un pasaje del Fedón, en el que Platón intenta mostrar que es posible desentenderse del cuerpo “en la medida de lo posible”. La tesis de que el alma va ganando “claridad” a medida que va ascendiendo desde la εἰκασία hasta la νόησις, sostengo, podría entenderse como “certeza”: como algunos epistemólogos contemporáneos, Platón parece haber visualizado la idea de que, si hay conocimiento, tal conocimiento debe ser cierto, y tal certeza, sugiero, no se entiende como una mera certeza ‘psicológica’, sino como una certeza ‘epistémica’. Es decir, las razones que el sujeto cognoscente platónico posee son lo suficientemente fuertes como para creer que lo que cree es verdadero. (shrink)

This paper presents a new interpretation of the objects of dianoia in Plato’s divided line, contending that they are mental images of the Forms hypothesized by the dianoetic reasoner. The paper is divided into two parts. A survey of the contemporary debate over the identity of the objects of dianoia yields three criteria a successful interpretation should meet. Then, it is argued that the mental images interpretation, in addition to proving consistent with key passages in the middle books of the (...) Republic, better meets those criteria than do any of the three main positions. (shrink)

I argue against a formidable interpretation of Plato’s Divided Line image according to which dianoetic correctly applies the same method as dialectic. The difference between the dianoetic and dialectic sections of the Line is not methodological, but ontological. I maintain that while this interpretation correctly identifies the mathematical method with dialectic, ( i.e. , the method of philosophy), it incorrectly identifies the mathematical method with dianoetic. Rather, Plato takes dianoetic to be a misapplication of the mathematical method by a subset (...) of practicing mathematicians. Thus, Plato’s critique of dianoetic is a not a critique of mathematics, as such, but of mathematicians. (shrink)

In a 1985 article entitled “The Art of Glaukos,” Diskin Clay suggested that the enigmatic passage at the beginning of the geological myth in Phaedoreferred toRepublic10, where the soul is likened to the sea-creature Glaucus whose true nature, like the soul’s, is obscured by the distortions imposed by underwater life. Starting with a defense of Clay’s ingenious suggestion, my purpose is to compare Phaedoto Glaucus, with its true nature obscured by traditional assumptions about the order in which Plato composed his (...) dialogues, and thus how they should be read. At least part of the reason that Clay’s thesis has not been embraced is because it clashes with the dogma that Phaedocannot refer back to Republic; I want to challenge that dogma. Borrowing from Catherine Zuckert the notion that, since Phaedocomes at the end of Socrates’ story, it can usefully be read as the culmination of the Platonic dialogues, I will show how a “late” Phaedo—i.e., a reading of the dialogue that is open to the possibility that it refers to more than one dialogue generally considered to be later than it with respect to composition—recovers its true nature, presently encrusted with the oysters and seaweed of an outdated developmentalism that has obscured this culminating masterpiece of Plato’s dramatic and philosophical art. (shrink)

Once we realize that the indivisible and infinitely repeatable One of the arithmetic lesson in Republic7 is generated by διάνοια at Parmenides 143a6-9, it becomes possible to revisit the Divided Line’s Second Part and see that Aristotle’s error was not to claim that Plato placed Intermediates between the Ideas and sensible things but to restrict that class to the mathematical objects Socrates used to explain it. All of the One-Over-Many Forms of Republic10 that Aristotle, following Plato, attacked with the Third (...) Man, are equally dependent on Images and above all on the Hypothesis of the One. (shrink)