Definitions (Plato)

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Horoi beginning. Codex Parisinus graecus 1807.jpg
The oldest, surviving manuscript of Definitions: Paris, Bibliothèque Nationale, Gr. 1807 (9th century), first page
Author Pseudo-Plato
LanguageAncient Greek

The Definitions (Greek : ὍροιHoroi; Latin : Definitiones) [1] is a dictionary of 184 philosophical terms sometimes included in the corpus of Plato's works. Plato is generally not regarded as the editor of all of Definitions. Some ancient scholars attributed Definitions to Speusippus. [2]

Greek language language spoken in Greece, Cyprus and Southern Albania

Greek is an independent branch of the Indo-European family of languages, native to Greece, Cyprus and other parts of the Eastern Mediterranean and the Black Sea. It has the longest documented history of any living Indo-European language, spanning more than 3000 years of written records. Its writing system has been the Greek alphabet for the major part of its history; other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems.

Dictionary collection of words and their meanings

A dictionary, sometimes known as a wordbook, is a collection of words in one or more specific languages, often arranged alphabetically, which may include information on definitions, usage, etymologies, pronunciations, translation, etc. or a book of words in one language with their equivalents in another, sometimes known as a lexicon. It is a lexicographical reference that shows inter-relationships among the data.

Plato Classical Greek philosopher

Plato was an Athenian philosopher during the Classical period in Ancient Greece and the founder of the Academy, the first institution of higher learning in the Western world. He is widely considered the pivotal figure in the history of Ancient Greek and Western philosophy, along with his teacher, Socrates, and his most famous student, Aristotle. Alfred North Whitehead once noted: "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato."


In modern scholarship, Definitions is thought to have little philosophical value. Given the sophistication of Plato's and Aristotle's efforts in the area of definition, this collection seems to be an elementary text produced by second-rate philosophical study.[ citation needed ] Its early date, however, does give it some importance as a source for the history of ancient Platonism. [3]


Definitions is a list of 184 terms important in early Platonism together with one or more brief definitions. Though not in alphabetical or any other simple order, it is possible to discern some features of the organization of the collection. Definitions 1–20 consist chiefly of terms from natural philosophy. Definitions 21–107, the main section of the collection, contain concepts from ethics (affects and virtues), political theory, logic, grammar, and epistemology. Definitions 108–184 are a final appendix that contains a mixture of concepts which sometimes duplicate earlier terms and therefore was probably added at a later date. There are few terms drawn from metaphysics. It is probable that the collection underwent changes through the centuries since the number of definitions in the surviving manuscripts varies. [4]

Methodologically, Definitions is related to the Platonic Method of Division (diairesis) that progresses from the more general to the more specific, i.e., from 'above' to 'below.' Definitions were constructed by first giving the genus of the thing to be defined and then giving more and more of its special characteristics (its differentia) until it was fully distinguished from other members of the genus. Such a definition therefore gives the lowest species for the thing defined. In Definitions, for example, the word definition is defined as an expression that is composed of genus and differentia. [5] Many definitions in Definitions follow these principles and define terms by giving their genus and distinguishing characteristics. A human, for example, is a two-footed animal without wings. [6] Here, two-footed animal is the lowest genus that contains humans and without wings distinguishes humans from all the other two-footed animals, i.e., from birds. Other definitions, however, consist only of lists of characteristics or are trivial explanations of words. Many concepts are defined simply by giving the distinguishing characteristic. Humans, for example, are also defined as the only rational animal.

Diairesis is a form of classification used in ancient logic that serves to systematize concepts and come to definitions. When defining a concept using diairesis, one starts with a broad concept, then divides this into two or more specific sub-concepts, and this procedure is repeated until a definition of the desired concept is reached. Apart from this definition, the procedure also results in a taxonomy of other concepts, ordered according to a general–specific relation.

Author and time of composition

There is a scholarly consensus that Definitions cannot be ascribed to Plato. However, many individual points rest on his doctrines and it is probable that the way of defining various concepts goes back to this teaching. It is thought certain that Definitions originated in the circles around the school of philosophy founded by Plato, i.e., in or around the Academy. The definitions were probably collected at the time of the Early Academy, and indeed in the period immediately following Plato's death, that is, in the second half of the fourth century or the first third of the third century BCE. Key Aristotelian terms such as 'potential' and 'actuality' are not conspicuous in Definitions.

It was conjectured that Definitions is a selection from a larger collection that was available in the Academy in that period, and may have been the foundation of a lost collection made by Speusippus, Plato's nephew and the second head of the Academy. [7] Today, however, the hypothesis that the extant collection is related to Speusippus' is no longer defended. [8] Whether Definitions is a compilation made from older collections is debated by scholars. [9]

Speusippus ancient greek philosopher

Speusippus was an ancient Greek philosopher. Speusippus was Plato's nephew by his sister Potone. After Plato's death, c.348 BC, Speusippus inherited the Academy, near age 60, and remained its head for the next eight years. However, following a stroke, he passed the chair to Xenocrates. Although the successor to Plato in the Academy, Speusippus frequently diverged from Plato's teachings. He rejected Plato's Theory of Forms, and whereas Plato had identified the Good with the ultimate principle, Speusippus maintained that the Good was merely secondary. He also argued that it is impossible to have satisfactory knowledge of any thing without knowing all the differences by which it is separated from everything else.


The existence of Definitions is first attested in the Roman imperial period. Until late antiquity, no one else but Plato was named as the author, [10] but the prevailing opinion was that the collection did not originate with him. It was not included in the tetralogical arrangement of Plato's works. The anonymous Prolegomena to Platonic Philosophy, which is dated to late antiquity, designates Speusippus as the author. [11]

The earliest, surviving manuscript is from the ninth century CE. [12]

Definitions was unknown to the Latin-speaking, scholarly world of the Middle Ages and was first rediscovered by Renaissance humanists. In the fifteenth century, the humanist Marsilio Ficino believed the collection's author was Speusippus. [13]

Ficino translated Definitions into Latin and published his translation in Venice in 1497 with Aldus Manutius, and named Speusippus as the author in the introduction. [14]

The first edition of the Greek text was brought out in Venice by Aldus Manutius in September 1513 as part of the complete works of Plato edited by Markos Musuros. This edition was the basis for the Latin translation that the humanist Willibald Pirckheimer brought out in Nuremberg in 1523 with the printer Friedrich Peypus. [15]

Editions and translations

The first printed edition of Definitions, Venice 1513, first page Horoi beginning. Editio princeps.jpg
The first printed edition of Definitions, Venice 1513, first page


  1. Henri Estienne (ed.), Platonis opera quae extant omnia, Vol. 3, 1578, p. 411.
  2. John Madison Cooper, D. S. Hutchinson (1997), Plato – Complete Works. Hackett Publishing. pp. 1677–1687.
  3. Hans Günter Zekl (ed.): Aristoteles: Organon, v. 2, Hamburg 1998, pp. LXIV, LXX–LXXII.
  4. Luc Brisson: Platon: Dialogues douteux et apocryphes. In Richard Goulet (ed.): Dictionnaire des philosophes antiques, v. 5, part 1, Paris 2012, pp. 833–841: 839; Joseph Souilhé (ed.): Platon: Œuvres complètes, v. 13, part 3, 2nd edition, Paris 1962, p. 157ff.
  5. Definitions 415a.
  6. Definitions 415a.
  7. Hans Krämer: Die Ältere Akademie. In Hellmut Flashar (ed.): Grundriss der Geschichte der Philosophie. Die Philosophie der Antike, v. 3, 2nd edition, Basel 2004, pp. 1–165: 96; Hans Günter Zekl (ed.): Aristoteles: Organon, v. 2, Hamburg 1998, p. LXIX. Joseph Souilhé (ed.) argues for a later date: Platon: Œuvres complètes, v. 13, part 3, 2nd edition, Paris 1962, p. 157 ff.; cf. Margherita Isnardi: Nomos e basileia nell’Accademia antica. In La Parola del Passato 12, 1957, pp. 401–438: p. 429 and note 2; Heinz Gerd Ingenkamp: Untersuchungen zu den pseudoplatonischen Definitionen, Wiesbaden 1967, pp. 106–110.
  8. Leonardo Tarán: Speusippus of Athens, Leiden 1981, p. 197.
  9. This is maintained by Heinz Gerd Ingenkamp: Untersuchungen zu den pseudoplatonischen Definitionen, Wiesbaden 1967, pp. 110–112. Konrad Gaiser rejects this in his review of von Ingenkamp's work in Gymnasium (newspaper) 76, 1969, pp. 543–546: 544 ff.
  10. Heinz Gerd Ingenkamp: Untersuchungen zu den pseudoplatonischen Definitionen, Wiesbaden 1967, p. 112 ff.
  11. „Prolegomena zur Philosophie Platons“ 26, ed. by Leendert G. Westerink: Prolégomènes à la philosophie de Platon, Paris 1990, p. 38 ff.
  12. Joseph Souilhé (ed.): Platon: Œuvres complètes, v. 13, part 3, 2nd edition, Paris 1962, p. 158 ff.
  13. For Ficino's hypothesis see Antonio Carlini: Alcune considerazioni sulla tradizione testuale degli scritti pseudoplatonici. In Klaus Döring et al. (ed.): Pseudoplatonica, Stuttgart 2005, pp. 25–35: 31f; James Hankins: Plato in the Italian Renaissance, 3rd edition, Leiden 1994, p. 307.
  14. James Hankins: Plato in the Italian Renaissance, 3rd edition, Leiden 1994, p. 742 ff.
  15. For Pirckheimer's translation see Niklas Holzberg: Willibald Pirckheimer, München 1981, pp. 301–311.

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