Aristotle: Criticism of Plato

Aquinas consistently criticizes Plato and his followers for their commitment to the existence of separate forms or ideas. There is no whiteness existing by itself apart from any particular white things or any particular person's thoughts about them. The same goes for every natural form, from humanity to heat. And yet Aquinas is happy to appeal to such separate forms as examples to illustrate his own metaphysical views. This seems like a strange and dangerous procedure. If Aquinas considers Platonic forms (...) to be incoherent, then surely their incoherence will infect the notions he uses them to illustrate. But does Aquinas consider Platonic forms to be incoherent? I don't think so. The very fact that he uses them as examples to illustrate his own views suggests otherwise. And at one point Aquinas even grants that God could create a Platonic form such as a separate whiteness. Why, then, does he reject such forms? What has Aquinas got against them? An examination of his main critical discussions of Platonic forms shows that he rejects them not because he thinks they are impossible, but because he thinks they are unnecessary. In other words, Aquinas rejects Platonic forms on grounds of parsimony, since he thinks they cannot explain any of the things that Plato posited them to explain, such as the changes things undergo, the nature and existence of things, and our knowledge of them. Where Plato's separate forms fail, however, Aquinas thinks Aristotle's inherent forms succeed. (shrink)

Sense experience, naïvely conceived, is a way of knowing perceptible properties: the colors, sounds, smells, flavors, and textures in our perceptual environment. So conceived, ordinary experience presents the perceiver with the essential nature of a property like Sky Blue or Middle C, such that how the property appears in experience is identical to how it essentially is. In antiquity, as today, it was controversial whether sense experience could meet the conditions for knowledge implicit in this naïve conception. Aristotle was a (...) partisan in this debate, but his position is poorly understood. This dissertation examines how Aristotle’s perceptual psychology responds to ancient challenges to the naïve conception, and so articulates his defense of perceptual knowledge. -/- Aristotle’s defense relies on an ontology of “perceptual qualities"—a core class of perceptible properties—according to which those qualities, despite having a perceiver-independent essence rooted in the physics of causation and affection, nevertheless can be present in experience as they essentially are. Chapter 1 defends this realist and objectivist reading against competing interpretations, which overlook a crucial distinction between perceptual qualities and perceptual objects. Chapter 2 presents Aristotle’s ontology as a physicalism that uncharacteristically allows for perceptual qualities to appear in experience as they essentially are. -/- This ontology informs Aristotle’s account of the psychological conditions under which perceivers actually are presented with the essence of perceptual qualities. The locus of this account is an obscure passage where Aristotle purports to show that the senses “discriminate” perceptual qualities because the senses are “mean states” (An. 2.11, 424a5–7). Chapter 3 develops a comprehensive interpretation of the sensory mean state, which Chapter 4 uses to elucidate Aristotle’s argument for sensory discrimination. Sensory discrimination turns out to be a process in which the essence of a perceptual quality comes to be present in the affection it produces in a perceiver. For Aristotle, this shows that sense perception meets a condition for knowledge that his predecessors, including Plato, thought it could not meet. For in his view, but not in theirs, sense experience shares in both the truth and the essence of the qualities it perceives. (shrink)

Y a-t-il des Idées et peut-on démontrer qu’elles existent ? Parmi les protagonistes anciens de la controverse qui a opposé partisans et adversaires des Idées, Aristote mérite une attention toute particulière. De fait, si – au moment où Aristote intervient dans le débat autour de l’hypothèse des Idées – ce débat a déjà une histoire, c’est avec lui que cette histoire atteint une maturité qui est à la fois d’ordre doctrinal et doxographique. De fait, non seulement Aristote est le premier (...) à avoir défini certaines au moins des propriétés de ce qui est et se dit en commun de plusieurs, mais encore a-t-il pris soin d’inscrire ces définitions dans la continuité de l’héritage socratique dont il s’est explicitement revendiqué tout en dénonçant sa dérive aux mains des successeurs de Socrate. L’objectif principal du cycle de conférences a été d’étudier les objections qu’Aristote a formulées à l’encontre des partisans des Idées en prenant comme fil conducteur la notion de substance que sa discussion des Formes platoniciennes tantôt présuppose, tantôt mobilise explicitement. Pour ce faire, nous avons procédé à une lecture détaillée d’un certain nombre de documents, tirés aussi bien de ses écrits d’école que des vestiges de ses traités perdus, où Aristote rejette la notion d’un universel substantiel (autant dire, en l’occurrence, séparé) et s’efforce de mettre à mal les arguments que ses partisans avançaient pour prouver son existence. (shrink)

The opening argument in the Metaphysics M.2 series targeting separate mathematical objects has been dismissed as flawed and half-hearted. Yet it makes a strong case for a point that is central to Aristotle’s broader critique of Platonist views: if we posit distinct substances to explain the properties of sensible objects, we become committed to an embarrassingly prodigious ontology. There is also something to be learned from the argument about Aristotle’s own criteria for a theory of mathematical objects. I hope to (...) persuade readers of Metaphysics M.2 that Aristotle is a more thoughtful critic than he is often taken to be. (shrink)

Do Ideas exist and can we prove it ? Do proofs of their existence have all the same value or not ? Aristotle addresses these issues in two famous documents of the controversy that pitted supporters of the theory of Forms against its opponents within Plato’s Academy : his lost work, quoted by Alexander of Aphrodisias by the title of Peri Ideon, and the lengthy thrust against Ideas that can be read, with some minor variations, in books A, chapter 9, (...) and M, chapter 4, of his Metaphysics. As we only have fragments of the first, the second being laconic and little more than a summary, there has been much speculation about the exact number and nature of the arguments for and against the Forms. Since the pioneering works of Léon Robin, Paul Wilpert et Harold Cherniss, one problem in particular has attracted the attention of specialists : what arguments does Aristotle accuse of either producing Ideas on relatives for one or of dragging in the « Third Man » for another ? Why does he consider these arguments to be more rigorous than the others ? If we are not dealing with the same arguments, how can these be more or better argued than those mentioned by Aristotle in the same breath, namely the arguments Plato’s followers took from the sciences, the one over many and the thought about things that have perished ? Through detailed analysis of texts from the Corpus Aristotelicum and Alexander’s commentary on Aristotle’s Metaphysics, Rationes ex machina develops a new interpretation of the controversial file of the akribesteroi tôn logôn as well as a micrological solution to the puzzle that has come to be a sort of compulsory figure of the exegesis of the Aristotelian criticism of « Plato’s Ideas ». (shrink)

In reply to Seddon's charge that Long's analysis in Reason and Value rests on a mistaken reading of Plato, Long both defends his interpretation of Plato and argues that nothing in Reason and Value depends on Plato interpretation in any case.

I argue here that a properly Platonic theory of the nature of number is still viable today. By properly Platonic, I mean one consistent with Plato's own theory, with appropriate extensions to take into account subsequent developments in mathematics. At Parmenides 143a-4a the existence of numbers is proven from our capacity to count, whereby I establish as Plato's the theory that numbers are originally ordinal, a sequence of forms differentiated by position. I defend and interpret Aristotle's report of a Platonic (...) distinction between form and mathematical numbers, arguing that mathematical numbers alone are cardinals, by reference to certain non-technical features of a set-theoretical approach and other considerations in philosophy of mathematics. Finally I respond to the objections that such a conception of number was unavailable in antiquity and that this theory is contradicted by Aristotle's report in Metaph . XIII that Platonic numbers are collections of units. I argue that Aristotle reveals his own misinterpretation of the terms in which Plato's theory was expressed. (shrink)

In Chapter 9 of the first book of the Metaphysics Aristotle criticizes “those who posit the Ideas as causes”. His second group of criticisms urges that “the ways in which we try to prove that the forms exist” are unsatisfactory, and he enumerates five such ‘ways’. Alexander of Aphrodisias, in his commentary on the passage, offers to explain in more detail what the five ways were and why each is a cul-de-sac. Gail Fine’s On Ideas is a commentary on this (...) section of Alexander’s commentary on Aristotle. (shrink)

The book is a reconstruction and detailed presentation (close to a commentary) of Aristotle's lost work On Ideas, based, in the main, on the testimony of Alexander of Aphrodisias in his commentary to the Metaphysics; Alexander's text is included in the critical edition by D. Harlfinger.

Das historische Buch konnen zahlreiche Rechtschreibfehler, fehlende Texte, Bilder, oder einen Index. Kaufer konnen eine kostenlose gescannte Kopie des Originals durch den Verlag. 1907. Nicht dargestellt. Auszug:... I. TEIL DIE PROBLEME DER GRUNDWISSENSCHAFT ndem wir nunmehr an die von uns zu behandelnde Wissenschaft herantreten, gilt es zunachst uns klar zu werden uber die Fragen, uber die wir eine Entscheidung zu treffen haben. Es sind zum Teil solche, uber welche die Denker vor uns abweichende Ansichten geaussert haben; wir mussen aber auch (...) an etwaige weitere denken, die sie ubersehen haben mochten. Wer einer Sache recht auf den Grund kommen will, fur den ist das erste Erfordernis dies, dass er den Problemen scharf ins Gesicht sehe. Denn die nachher zu erlangende Einsicht hangt an der Losung der vorher ins Auge gefassten Probleme; wer den Knoten nicht kennt, der kann ihn auch nicht losen. Solch ein Knoten in dem Objekte aber ist es, den das Problem darstellt, wie es sich fur das Nachdenken auftut. Dem Denken namlich, sofern es die Schwierigkeit gewahr wird, ergeht es ganz ahnlich wie den Leuten, die sich durch einen festen Knoten eingeschnurt fuhlen: beide konnen keinen Schritt vorwarts tun. Darum ist es notig, zuvorderst alle Schwierigkeiten ins Auge gefasst zu haben; ist es schon aus diesem Grunde geboten, so ist ein weiterer Grund der, dass man, wenn man ohne diese Erwagung der Probleme an die Untersuchung herantritt, dem Wanderer gleicht, der nicht weiss, wohin er seinen Weg zu richten hat; und dass man ausserdem im andern Fall nicht einmal, wenn man etwas gefunden hat, zu erkennen imstande ware, ob das Gefundene auch das ist, was man sucht, oder nicht. Denn in jenem Fall ist das Ziel nicht klar; wohl aber ist es dem klar, der zuvor die Probleme sich zum Bewusstsein gebracht hat. Daz. (shrink)