The Anonymous Commentary on Plato's Theaetetus is a partially extant Ancient Greek philosophical commentary from the early Roman era that contains an exposition on Plato's Theaetetus. The composition of the text has been dated to some time between the late 1st century BCE through the middle of the 2nd century CE, making it one of the few surviving historical examples of Middle Platonist literature.
In the surviving portion of the commentary, the anonymous commentator discusses major themes of Plato's theories of knowledge such as Definitions of knowledge, Justified true belief, and the Problem of the criterion, and compares the account of knowledge in the Theaetetus to the Meno, Protagoras and the Sophist (dialogue). In addition, the commentator provides a summary of other interpretations of the dialogue during his time and presents a number of arguments against rival philosophical schools, especially Stoicism, Academic skepticism, and Pyrrhonism. The commentator also provides an in-depth analysis of the mathematical proof given by Theodorus of Cyrene and adds background historical detail on many of the people in the story and speculations on Plato's intentions in composition of the work.
The commentary was lost along with the majority of Commentaries on Plato and did not survive to the Medieval era in any known manuscript tradition. It was entirely unknown until the chance discovery in 1901 of a single papyrus roll dating to the middle of the 2nd century CE. The very beginning of the work is missing and the work cuts off partway through the dialogue. Its publication in 1905 attracted little interest at the time, as the commentators were not seen as original philosophers by classical scholarship of the time. In the second half of the 20th century, however, renewed interest in Ancient Roman philosophy and the philosophy of the ancient commentators has elevated it to one of the most important primary sources documenting the historical developments of Platonism and the commentary tradition in the early centuries of the Roman Empire.
Style, dating and authorship
Style
In addition to original philosophical works, many philosophers in antiquity wrote commentaries, most commonly on the works of other philosophers such as Plato and Aristotle, but also interpretive commentaries on religious or literary texts. Rather than simply reviewing or summarizing a philosophical or religious text, these works went through a line-by-line, highlighting specific passages and providing background or expositions. Many philosophical commentaries were intended as school notes, that expanded on the details of a philosophical work for students and clarified the meanings of obscure words, while others were more complex expositions and interpretations that were intended for a more advanced audience within a philosophical school. The Theaetetus commentary contains elements of both kinds of commentary.
The Anonymous Theaetetus commentary is the earliest surviving commentary on a work of Plato. Philosophical commentaries had been written long prior, the earliest evidence of any philosophical commentary is on the works of Homer, and one of the earliest surviving philosophical commentaries on any type of work is the Derveni papyrus, a 4th-century BCE papyrus that contains an allegorical philosophical commentary on an Orphic cosmogony that dates to the middle of the 5th century BCE. The first known commentary on a work of Plato specifically was written in the third century BCE by Crantor of Soli, the last scholarch of the Old Academy, which has been lost, but many later works written by Neoplatonists from the 3rd through 6th centuries CE have been preserved.
Dating The commentary is generally believed to date from 45 BCE to 150 CE, although attempts to establish a more exact dating have proven contentious. The fragmentary nature of the work make questions of the date and authorship of the work difficult to answer more exactly, as few other philosophical works from the period have survived. Based on its content, the commentary must date from the 1st century BCE or later; as a work of Middle Platonism that ascribes positive doctrines to Plato and disputes the Academic Skepticism that was dominant in the Hellenistic period and synthesizes the doctrines of the Stoics. The commentary must also have been written at the latest in the first half of the second century CE, when the papyrus that the surviving copy of the text has been dated to.
Authorship Although no part of the work survives which would allow a definitive identification of its author, the author can be identified as a Middle Platonist on the basis of doctrinal content within the text. The Middle Platonists, beginning with Antiochus of Ascalon, had rejected the skepticism of the Platonic Academy that had been dominant in Hellenistic philosophy, advocating a more dogmatic form of Platonism. Many Middle Platonists attempted to synthesize Platonic doctrines with either Stoicism or Aristotelianism; Antiochus had preferred the Stoics, while the Anonymous Commentator prefers Aristotle while criticizing the Stoics.
There have been attempts to identify the author with known Middle Platonists; John M. Dillon, seeing a similarity with the School of Gaius the Platonist, identifies him with the mid 2nd century CE philosopher Albinus, while Harold Tarrant says the best known candidate is the much earlier Eudorus of Alexandria, in the late 1st century BCE.
Content The commentary is on Plato's Theaetetus, one of his major works of epistemology. In the dialogue, Socrates and an Athenian youth named Theaetetus, investigate the nature of knowledge (episteme). Like many of the characters in Plato's dialogues, Theaetetus is a historical figure who is known to us independently of Plato. Both Theaetetus and his mentor, Theodorus of Cyrene were Ancient Greek mathematicians who are known through citation of their work in theorems proved in Euclid's Elements by later mathematicians. After a more general discussion of knowledge and understanding where they work through a mathematics problem Socrates and Theaetetus then discuss three potential definitions - knowledge as perception, knowledge as true belief (pistis), and knowledge as "justified true belief," although the dialogue ultimately ends in aporia as this definition, too, is shown to be unsatisfactory.
The commentary is only partially preserved, starting in the middle of the introduction to the commentary itself and cutting off partway through. The extant portion covers only the beginning 15%142e-153e, with an additional fragment from 157e to 158a of the dialogue which begins its coverage of the Theaetetus at the end of the prelude, a brief frame story. In this portion of the Theaetetus covered by the dialogue, Socrates asks Theodorus if he has any promising geometry students, and Theodorus introduces him to Theaetetus.143d - 144e Socrates challenges Theaetetus to explain to him the nature of knowledge,145c and they proceed to discuss the difference between knowledge and wisdom145d-146a and the differences between examples of knowledge and knowledge itself.146d-147c Theaetetus gives an example of a mathematical proof,147d-148b and Socrates explains his philosophical method for bringing out ideas, which he compares to midwifery (Maieutics). Socrates and Theaetetus then begin to discuss knowledge gained from sense-perception and examine Protagoras' famous maxim "Man is the measure of all things," and Heraclitus' theory of flux, although the commentary cuts off partway through this discussion. The commentator follows along the dialogue, adding explication of the readings of certain parts of the dialogue, giving cultural or historical background, and occasionally going into in-depth explication of certain philosophical arguments.
Introduction Most ancient commentaries on Plato and Aristotle begin with an introductory preface explaining the work being commented on. However, the first column of text from the papyrus this commentary is very fragmentary, rendering it unreadable, so the surviving portion of the text begins in the middle of this introduction. The surviving text opens at the end of an explanation of the purpose (skopos) of the Theaetetus dialogue, which the commentator claims is catharsis against the relativist doctrine of Protagoras, a Sophist from the 5th century BCE who taught that "Man is the measure of all things" and whose work On Truth the commentator claims Theaetetus had recently read. The commentator then states that some other Platonists believe that the purpose of the dialogue is to outline the Problem of the criterion, to give an argument in the Theaetetus about what knowledge is not (i.e. sense perception) in order to follow it up in the Sophist, with what knowledge is (i.e. the forms). However, the commentator says that these people are mistaken, and that the true purpose of the dialogue is to explain what the essence (ousia) of knowledge is.Comm. II-III in
The commentator then discusses the content of the prologue, which relates a frame story in which the dialogue between Theaetetus and Socrates is being recounted from a book by Euclid of Megara, a Socratic philosopher who founded the Megarian school. The commentator interprets the prologue as a propaedeutic demonstration of practical ethics; Euclid, as a distinguished Socratic philosopher, is being used as a model for how one ought to behave. This is in opposition to the Stoic doctrine of kathekon, which taught that "proper function" could be achieved through deduction rather than practice by example. The commentator then abbreviates his justification for this claim, and refers the reader to (no longer extant) works of "the Socratics" which he says explain this argument in further detail.Comm. III-IV in
Difference between Cyrene and Athens In the dialogue, Theodorus of Cyrene and Socrates discuss the youth of Athens, and Socrates begins with remark about how he cares more for the youth of Athens than the youth of Cyrene. The commentator states that Socrates surely also cares for the Cyreneans, but that as an Athenian he naturally cares more for the youth of his own city due to the phenomenon of Oikeiôsis, often translated as "appropriation." The commentator then goes on to discuss the Stoic and Epicurean doctrine of appropriation, which bases justice on this intuitive feeling. The commentator argues that, because we naturally have more intense feelings of appropriation towards ourselves and our own neighbors rather than strangers, people who based their notion of justice on appropriation will preferentially act in their own interest rather than acting justly. Then the commentator cites an example of a shipwreck, the Plank of Carneades, where someone who based their morality on these intuitive feelings would choose to save a friend or neighbor over a stranger, and that even if this never occurs, the claim is still refuted. The commentator then relates an argument from the Academic skeptics against the Stoics and Epicureans, where he argues that those who fail to preserve justice in equal measure must necessarily fail to preserve it at all. The commentator says that Plato did not base justice on appropriation, but on "becoming like a God" referring to a later part of the Theaetetus,184d which he states that his commentary will discuss at that point, which is however not in the extant portion of the text.Comm. V-VIII in
Nature of the soul