The Scope of Philosophy (I)

Philosophy in the middle of the 1st millennium BCE covered a large range of subject areas, including ontology, epistemology, justice, beauty, virtue, morals and ethics. The best way of getting an overview of its sheer range in the classical and post-classical worlds of antiquity is to look at the systematic arrangements created by Alexandrian scholars for the works of Plato. They did this for Plato because Plato was the philosopher whose canon of works was the most difficult to understand. The arrangments are not consistent with each other, but both reveal the scope of philosophical thought during the classical period.

There is also Aristotle's Protrepticus, which is an invitation to philosophy. Part of it survives in a text of Iamblichus. This unacknowledged addition to Iamblichus's text tells us something of how neophytes were to be attracted to philosophy. [It was common in antiquity not to reference all quotations, especially those which were likely to be well known to the author's readers. This is true in the case of the Protrepticus: most of Iamblichus's readers would have recognised its authorship immediately.]

Beyond the range of subjects covered, there are also the technical approaches to analysis and discussion of these subjects. The principal of these is dialectic, which is easily defined as the process of collection and division.

At the time K.F. Herman wrote his Life of Plato in the early nineteenth century, no means of establishing the chronology of the dialogues existed. In antiquity the dialogues were grouped thematically, according to the assumed method and purpose of the dialogues. This is how they are arranged by Diogenes Laertius in Bk iii ‘Plato’ [iii. 50-51] There was no agreement in antiquity however as to how these dialogues ought to be arranged. Diogenes gives another arrangement, that made by Thrasylus iii. 57-61; and an arrangement accepted by Aristophanes the grammarian iii. 62.

[see Sandys i.126: where he states that Aristophanes of Byzantium (c257 - c180 BCE) succeeded Eratosthenes as Librarian at Alexandria c195 BCE, and that he was the pupil of Zenodotus, Callimachus and Eratosthenes. It was he who “reduced accentuation and punctuation to a definite system” and devised marks to indicate spurious passages, tautologies, etc. Since Diogenes mentions similar (though not identical) critical marks in the texts of Plato he or perhaps his source would appear to have been using editions produced in Alexandria, or perhaps in the library of Pergamum around the time of Antigonus of Caryotus (author of a life of Zeno – see Diog. Laert. iii. 66): Sandys  History of Classical Scholarship vol. I.].

No simple list of Plato’s complete works is given by Diogenes as he does in the case of Aristotle and other philosophers.

I give the thematic arrangements of Diogenes and Thrasylus here. I've keyed the latter to Diogenes arrangement, which indicates just how hit and miss this approach is.

 Diogenes on the division of the Dialogues (iii. 49-50)

		Logical A	Statesman, Crat., Parm., Soph.
	Theoretical
		Physical B	Timaeus
Instructive
		Ethical C	Apol., Crito, Phaed., Phaedr., Symp., Menex., Clitoph., Epistles, Phileb., Hipparchus., Rivals
	Practical
		Political D	Republic, Laws, Minos, Epinomis, Critias
		Midwifery E	Alcibiades, Theages, Lysis, Laches
	Mental Gymnastics (obstetrics)
		Tentative F	Euthyphro, Meno, Io, Charmides, Theaetetus
Inquisitive
		Critical Objections G	Protagoras
	Controversy
		Subversive H	Euthydemus, Gorgias, Hippias Maj. & Min.

Tetralogies of Thrasylus (Diog. Laertius ii. 57-61) 

1st:	Euthyphro or On Holiness; Apology of Socrates; Crito or On what is to be done ; Phaedo or On the Soul.	F C C C	2nd:	Cratylus – On Correct Use of Names; Theaet. – On Knowledge; Sophist – On Being; Statesman – On Monarchy.	A F A A
3rd:	Parmenides – On Ideas; Philebus – On Pleasure; Symposium; Phaedrus – On Love.	A C C C	4th:	Alcibiades – On the Nature of Man 2nd Alcibiades – On Prayer; Hipparchus – Love of Gain; Rivals – On Philosophy.	E E C C
5th:	Theages – On Philosophy; Charmides – On Temperance; Laches – On Courage; Lysis – On Friendship;	E F E E	6th:	Euthyd. The Eristic; Protag. Or Sophists; Gorgias On Rhetoric; Meno On Virtue	H G H F
7th:	Hippias On Beauty; Hippias On Falsehood; Ion On the Iliad; Menexenus Funeral Oration;	H H F C	8th:	Clitophon (the Introduction); Republic On Justice; Timaeus On Nature; Critias Story of Atlantis; [in iii.60 Diog. Says Critias is ethical, but at iii.50 it is political, though not mentioned by name, only as a dialogue concerning Atlantis]	C D B D
9th	Minos On Law; Laws; On Legislation; Epinomis Nocturnal Council, or Philosopher; Epistles (all 13) [Welfare]	D D D C

We are very fortunate to have Diogenes Laertius' work, since it is the only historical account of philosophy surviving from antiquity which gives us details of the lives of the philosophers. We are unfortunate in the same regard, since Diogenes was a compiler, and a compiler of materials which sometimes he did not understand at all. It is often obvious when he is copying materials of much higher quality than appear elsewhere in his work. There are for example some details about the scope of Pythagoras's philosophy which he does not understand, but he includes them anyway, without useful context. I'm grateful to him for doing this, because sometimes it is possible to recognise the proper context from a reading of  other philosophers, such as Plato and Porphyry.

Not only have the other historical surveys of Greek philosophy disappeared, except as excerpted and copied in the pages of Diogene's Lives of the Philosophers, but it seems possible that the size of the work was greater in the late middle ages (14th century) than it is now, according to a statement by the monk Walter Burley.

Another puzzle about Diogenes is his date. He could have been writing anytime from the life of Sextus Empiricus, who he mentions, up until the 5th century of our era. But there are no mentions of the later platonists, who we know as neoplatonists.