A New Testimony on the
Platonist Gaius
Michele Trizio
A
a single Delphic inscription (FD III.4 103),
the testimonia of the life and work of second-century
Middle Platonist Gaius fall into two classes.1 The first
includes first-hand observations of later philosophers up to
Proclus: Porphyry, for instance, reports that Gaius was one of
several authors read regularly by Plotinus’ entourage.2 Galen
tells us that he followed the classes of two of Gaius’ pupils in
Pergamum and Smyrna respectively.3 As to Proclus, he twice
mentions Gaius, among other Platonists, in his commentaries
on the Republic and the Timaeus.4 The second class of testimonia
includes statements concerning Gaius’ scholarship on Plato in
three important Greek MSS. The first of these, Paris.gr. 1962, is
a ninth-century MS. of the so-called ‘philosophical collection’,
which, among others entries, contains a pinax at f. 146v mentioning ᾿Αλβίνου τῶν Γαίου σχολῶν ὑποτυπώσεων πλατωνικῶν
δογµάτων. That is to say, Albinus’ edition of Gaius’ scholia on
PART FROM
1 On Gaius and the related bibliography see J. Whittaker, “Gaius,” in R.
Goulet (ed.), Dictionnaire de philosophes antiques III (Paris 2000) 437–440. All
testimonia on Gaius are collected and discussed with reference to previous
literature in A. Gioè, Filosofi medioplatonici del II secolo d.c. (Naples 2002).
2 V.Plot. 14, ed. P. Henry and H.-R. Schwyzer, Plotini opera I (Leiden
1951) 19.10–14.
3 De propriorum animi 41, ed. W. de Boer (CMG V.4.1.1, Leipzig 1937);
Libr.propr. 2.1, ed. V. Boudon-Millot (Paris 2007).
4 In Ti. I 340.24 Diehl; In R. II 96.11–13 Kroll.
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MICHELE TRIZIO
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Plato were probably included in this MS. and only later lost.5
Finally, the tenth-eleventh century Paris.Coisl. 387 (at 154v) and
the fifteenth-century Bodleianus Auct. T.2.11 (at 359r) mention
Gaius, among others, as the author of useful commentaries.
This paper argues that a middle Byzantine treatise on De
interpretatione 7, which has so far passed unnoticed, should be
added to these testimonia. The eleventh-century scholar John
Italos, pupil of Michael Psellos,6 wrote several short treatises on
Aristotle’s De interpretatione dealing with specific sections or
passages of the text;7 unlike his master, who paraphrased the
entire text of the Aristotelian work in question, Italos’ comments on De interpretatione are all short and discuss parts or
5 On this MS. and its history see J. Whittaker, “Parisinus graecus 1962
and the Writings of Albinus. Part I,” Phoenix 28 (1974) 320–354 (repr. Studies
in Platonism and Patristic Thought [London 1984] XX); F. Ronconi, “Qualche
considerazione sulla provenienza dei modelli della ‘collezione filosofica’:
note a margine del Paris. gr. 1962,” in D. Bianconi and L. del Corso (eds.),
Oltre la scrittura. Variazioni sul tema per Guglielmo Cavallo (Paris 2008) 125–142.
For an overview on the ‘philosophical collection’ and the large number of
studies on it see G. Cavallo, “Qualche riflessione sulla ‘collezione filosofica’,” in C. d’Ancona (ed.), The Libraries of the Neoplatonists (Leiden 2007)
155–156. For a new interpretation of the editorial project or projects behind
the ‘philosophical collection’ see F. Ronconi, “La collection brisée. Pour
une étude des milieux socioculturels liés à la ‘collection philosophique’,” in
P. Odorico (ed.), La face cachée de la littérature byzantine (Paris 2011) 137–166.
6 On Italos see A. Rigo, “Giovanni Italo,” in Dizionario biografico degli
Italiani 56 (Rome 2001) 62–67.
7 P.-P. Joannou, Joannes Italos. Quaestiones quodlibetales (Ettal 1956): e.g. 29–
37, q. 28 Εἰς τὸ Περὶ ἑρµηνείας ἔκδοσις ἐπίτοµος; 40–41, q. 30 Πῶς τοῦ
Ἀριστοτέλους φήσαντος τὴν τὶς καὶ τὴν οὐ πᾶς ἐπὶ τῆς ἐνδεχοµένης καὶ
µόνης ὕλης συναληθεύειν, αὗται καὶ ἐπὶ τῆς ἀναγκαίας ἀληθεύουσαι φαίνονται· τὶ γὰρ ζῷον ἄνθρωπος καὶ οὐ πᾶν ζῷον ἄνθρωπος; 45–47, q. 37
∆ιατί παθήµατα καλεῖ ὁ Ἀριστοτέλης τὰ νοήµατα τῆς ψυχῆς; 55, q. 44
∆ιατί ἡ πᾶς καὶ ἡ οὐδεὶς λέγονται ἐναντίαι; 55–58, q. 45 Εἰς τὸ Περὶ
ἑρµηνείας; 58–60, q. 46 Πρὸς τοὺς λέγοντας ὅτι πῶς ἂν εὑρεθείη ἀντίφασις
ἐπὶ τῆς ἀδυνάτου ὕλης, διὰ τὸ δοκεῖν τὴν οὐ πᾶς παρεισφέρειν τὴν τὶς, οἷον
πᾶς ἄνθρωπος ἵπταται, οὐ πᾶς ἄνθρωπος ἵπταται; 61–63, q. 49 Εἰς τὸ Περὶ
ἑρµηνείας ἔκδοσις; 72–73, q. 53 Περὶ µίξεων; 133, q. 83 Περὶ προτάσεων;
134, q. 85 Περὶ ἀκολουθίας προτάσεων.
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A NEW TESTIMONY ON THE PLATONIST GAIUS
single passages. One short text of the latter type has been transmitted by one of Italos’ students as a report of a lecture given
by the master, as is clear from the formulation Ἰωάννης ὁ
φιλόσοφος ὁ Ἰταλός, ὁ ἡµέτερος διδάσκαλος, οὕτως etc. The
text deals with De interpretatione 7 (17a38–17b16), where Aristotle discusses terms and propositions that are contradictories.
However, the first part of this text is problematic and deserves
attention (55.1–7, q. 44 ):
∆ιατί ἡ πᾶς καὶ ἡ οὐδεὶς λέγονται ἐναντίαι· ὁ µὲν οὖν Ἀµµώνιος
αἰτίαν ἀποδίδωσι διὰ τὸ µιµεῖσθαι τὰ ἔµµεσα ἐναντία· ὥσπερ
γὰρ ἐκεῖνα δύνανται ἀπεῖναι τοῦ ὑποκειµένου, οὕτω καὶ αὗται
συµψεύδονται· ὁ δὲ Πορφύριος διὰ τὸ πλεῖστον ἀλλήλων ἀφεστηκέναι ταῦτά φησιν ἐναντία· ἡ µὲν γὰρ πᾶς ὕπαρξίν τινα
παντελῆ σηµαίνει, ἡ δὲ οὐδεὶς παντελῶς ἀνυπαρξίαν· Γάϊος δὲ
ὁ φιλόσοφος οὕτως· ὥσπερ τὰ ἐναντία συµψεύδονται, οὕτω καὶ
αὗται, καὶ ὥσπερ ἐκεῖνα ἐν τῷ αὐτῷ ἀδύνατα εἶναι, οὕτω καὶ
ταύτας. Ἰωάννης ὁ φιλόσοφος ὁ Ἰταλός, ὁ ἡµέτερος διδάσκαλος,
οὕτως …
The references to Ammonius and Porphyry pose no problem
whatever. In fact, we know both Ammonius’ and Porphyry’s
views on contradictories from Ammonius’ commentary on De
interpretatione, the direct source of the doxography in this part of
the text.8 However, recognising that “Gaius the philosopher,”
the second-century Middle Platonist under discussion here,
held a view on this issue is unprecedented and requires discussion. Though this new testimony on Gaius is no less obscure
than those already known, it is different in one important respect: unlike the testimonia listed above, which do not mention
any of Gaius’ views, Italos’ is the first report of Gaius’ position
on an Aristotelian text or issue, namely the status of contradictories.
He is nevertheless a problematic witness. First of all, as I will
show, it is difficult to identify an accurate reference to a Middle
Platonic doctrine in Italos’ rudimentary report of Gaius’ po8 A. Busse, Ammonius, In Aristotelis de interpretatione commentarius (CAG IV.5,
Berlin 1897) 92.3–102.18.
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sition: “as it is impossible for the former [viz. non-exhaustive/
separated/polar contraries] to be present in the same thing, so
too it is impossible for the latter [‘all’ and ‘no’] to do so.”
Furthermore, neither the late antique nor the Byzantine commentary tradition on this Aristotelian work (or on any other
Aristotelian logical work) mentions Gaius at all. Boethius, Ammonius, Stephanus, the Anonymous Tarán, Michael Psellos,
Michael of Ephesus, Leo Magentinos, not one of these sources
gives the slightest clue as to Gaius’ views on terms or propositions as contradictories. The major known scholia concerning
this Aristotelian passage are equally silent.9
9 The commentaries by Michael Psellos, Michael of Ephesus, and Leo
Magentinos are not available in modern critical editions. For Psellos’ commentary, being aware of the many flaws of the 1503 Aldine edition (on
which see K. Ierodiakonou, “Psellos’ Paraphrasis on Aristotle’s De interpretatione,” in K. Ierodiakonou [ed.], Byzantine Philosophy and its Ancient Sources
[Oxford 2002] 157–181, at 161–163), I collated MS. Laur.Plut. 10.26 (ff.
149–176). After Bandini (A. M. Bandini, Catalogus codicum manuscriptorum
Bibliothecae Mediceae Laurentianae I [Florentiae, Typis Caesareis, 1764] 493) it
has become customary to date this MS. to the twelfth century and to believe
it to be the oldest MS. preserving this work. However, given the importance
of this witness of Psellos’ paraphrase of De Interpretatione, it should be assessed
according to its role within the tradition, and not simply according to its
dating, which however I challenge on the grounds that the handwriting in
this part of the MS. falls into the class of the Beta-Gamma style typical of the
second half of the thirteenth century. The traditional dating of this MS.
should therefore be corrected. Michael of Ephesus’ and Leo Magentinos’
commentaries on De interpretatione are found in the thirteenth-century Paris.
gr. 1917 (ff. 17r–45r), where Michael’s commentary has been copied in the
margin of Magentinos’ commentary. As for the scholia, to no avail I
checked Scholia in Aristotelem, collegit Christianus Augustus Brandis (Berlin
1836), and the following relevant MSS. known for containing scholia on the
text: Laur.Plut 72.5 (ff. 50r–67v, tenth century for this part of the text, with
scholia copied by the two main copyists of this portion of the MS. and by
later scribes, the scholia at ff. 53v–54r concerning De Interpretatione 7 and the
problem of contraries); Ambr. L 93 sup. (ff. 60v–79v, tenth century, copied in
southern Italy and later annotated by Constantinoplitan hands, the scholia
relevant to De interpretatione 7 at ff. 62v–64r). All MSS. have been collated via
digital reproduction or microfilm. Scholia ascribed to Olympiodorus have
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A NEW TESTIMONY ON THE PLATONIST GAIUS
Our knowledge of Gaius is so limited by lack of direct evidence on his teaching that, while acknowledging the possibility
that Italos may have found this reference in some sourcematerial unavailable to us, we should also ponder whether the
reading Γάϊος as found in the MSS. might not be authentic. In
order to verify this suspicion, I examined one of the two most
important MSS. preserving Italos’ work, Vat.gr. 316, a thirteenth-century palimpsest copied in southern Italy in the
Salento area by a scribe whose handwriting falls into the class
of the Barock-styl typical of the literary hands of this period from
this area.10 The MS. does indeed read Γάϊος, with the gamma in
capital form but in the same dimension as the rest of the letters,
the stroke above the word customary for the rendering of
proper names, and -ος abbreviated in the usual way, i.e. with
omicron superscribed.
A scribal mistake can only be admitted if this can be explained on palaeographical grounds. In our case the only alternative that one can take into consideration is the corruption,
which I regard as highly improbable, of Γα(λην)ός into Γάϊος.
Let us imagine for instance that one of the MSS. in the earlier
stages of the text tradition reported instead of iota a very short
lambda (which could easily be read as iota), or let us imagine an
itacism, a quite common phenomenon, which transformed an
eta into an iota. From Γάϊος then one could suggest that the correct reading should have been Γα(λην)ός. Unlike Gaius, Galen
is know to have dealt with Aristotle’s De interpretatione 7 directly
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been copied by a thirteenth-fourteenth century hand in the margin of the
text of De interpretatione in Vat.Urb.gr. 35 (tenth century, ff. 54v–73v), and have
been edited in L. Tarán, Anonymous Commentary on Aristotle’s De Interpretatione
(Meisenheim am Glan 1978) xxv–xli. These scholia also fail to mention
Gaius at all.
10 On this MS. see I. Mercati and P. Franchi de’ Cavalieri, Codices Vaticani
graeci I (Rome 1923) 467–474. The copyist’s literary hand has been studied
by D. Harlfinger, Die Textgeschichte der pseudo-Aristotelischen Schrift Περὶ ἀτόµων
γραµµῶν (Amsterdam 1971) 147. See also D. Arnesano, “Aristotele in terra
d’Otranto. I manoscritti fra XIII e XIV secolo,” Segno e testo 4 (2006) 149–
190, at 153–155.
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in his Institutio logica, a work which had no impact on later
commentators and whose authenticity was not accepted unanimously in the nineteenth century when it was discovered.11
Galen also informs us that he commented several times on De
interpretatione, on Theophrastus’ Περὶ καταφάσεως καὶ ἀποφάσεως, and on Eudemus’ Περὶ λέξεως,12 a circumstance which
could have made him an ideal candidate for restoring the true
identity of the author referred to in Italos’ text. However, this
solution too is problematic, especially because, like Gaius,
Galen is equally ignored in the earlier commentary tradition on
De interpretatione.
Furthermore, it would be improper to question and dismiss
Gaius as the appropriate reading in the MSS. tradition. In fact,
not everything written in antiquity in the commentary tradition
of De interpretatione has reached us.13 As a matter of fact, it might
11
Nowadays there seems to be general agreement on the authenticity of
the Institutio logica. The text is transmitted by only one MS. (Par.gr.suppl. 635,
thirteenth century, in bad state of preservation) discovered in 1844 by
Minoidas Mynas on Mt. Athos; ed. K. Kalbfleisch, Galeni Institutio Logica
(Leipzig 1896). The main objections against the authenticity of the work
were brought by C. Prantl, Geschichte der Logik im Abendlande (Munich 1855)
591–610), on the grounds of the many barbarisms in the Greek text and the
absence of this work in the list of his own works that Galen prepared to
counter the circulation under his name of writings which were not his.
Prantl nevertheless thought the work to be an authentic handbook of logic
of the Hellenistic era. Following up Prantl’s remarks on the authenticity of
the work, I. von Müller, “Über Galens Werk vom wissenschafftlichen Beweis,” AbhMünch 20.7 (1895) 403–478, rejected the attribution to Galen, but
defended that it contains many Galenic logical doctrines. It was again K.
Kalbfleisch, “Über Galens Einleitung in die Logic,” Jahrb.klass.Philol. Suppl.
23 (1897) 679–708), who defended the authenticity of the work and set the
foundation for its subsequent acceptance.
12 Galen Libr.propr. 14.11, 17.1, 17.2 (Theophrastus commentary), 17.3
(Eudemus commentary).
13 For an overview on the antique commentary tradition see C Hasnaoui,
“La tradition des commentaires grecs sur le De Interpretatione (PH) d’Aristote
jusq’au VIIe s.,” in Dictionnaire des philosophes antiques Suppl. (Paris 2003) 122–
173, at 137–158.
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A NEW TESTIMONY ON THE PLATONIST GAIUS
be that the reason for Gaius’ absence among the commentators
on De interpretatione is that he actually never wrote any commentary on it, but nevertheless held a position on the status of
contraries. It should also be remembered that the only two testimonia of Gaius found in MSS. are from the middle Byzantine
period, the very period in which John Italos floruit first as a
pupil of Psellos, then as “consul of the philosophers” in the
reign of Michael VII Doukas (1071–1078). Intriguingly, as we
have seen, one of these witnesses, Paris.gr. 1962, which includes
the pinax refering to Albinus’ edition of Gaius’ scholia on Plato,
most likely once contained the full text of Albinus’ work, lost
before Janos Lascaris brought the MS. to Italy in the late
fifteenth century.14
Whether this lost work contained anything that might have
formed the basis for Italos’ account of Gaius’ position on contradictories is a matter of pure speculation. There is however a
stronger argument for maintaining that Gaius is the right reading in Italos’ text and for accepting the witness transmitted by
this eleventh-century treatise on De Interpretatione 7 as trustworthy: as to the general interest in logic by the Middle
Platonists, who often attributed the invention of Aristotle’s logic
to Plato (see below), the surviving witnesses actually include
several texts discussing the problem of contradictory pairs
within a more general anti-Aristotelian reading of Aristotle’s
Categories, where the philosopher (13a37–b35) also discusses
contraries.15 Intriguingly, one reported statement by a Middle
Platonist on contraries, that of Nicostratus, is found in Simplicius’ comment on 13a37–b35, where, unsurprisingly, the
discussion is placed in the broader context of Aristotle’s De
interpretatione 7 and 9.16
14
See the literature cited in n.5 above.
On logic among the second-century Middle Platonists see P. Moraux,
Der Aristotelismus bei den Griechen II (Berlin/New York 1984) 519–561; J. M.
Dillon, The Middle Platonists2 (Ithaca 1996) 276–280.
16 Simplic. In Aristotelis Categorias commentarium, ed. K. Kalbfleisch (CAG
VIII, Berlin 1907) 406.6–407.14. On this passage see Moraux, Der Ari15
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It is obviously difficult to say whether Gaius shared Nicostratus’ negative view of Aristotle’s categories (which was preceded
by that of Eudorus),17 or whether he opted for a milder approach to this issue comparable to that of Albinus and the
anonymous commentator on Theaetetus, who found it natural to
trace Aristotle’s categories back to Plato’s Parmenides.18 But
clearly there was a debate occurring around Gaius on these
matters and there is no reason to preclude that Gaius had a
view on them, even though John Italos’ account of Gaius’
position leaves us with very little certainty as to the view that
Gaius actually did hold.
Italos’ report can be tentatively explicated as follows. As said
above, he ascribes to Gaius the view that “as it is impossible for
the former [i.e. non-exhaustive/separated/polar contraries] to
be present in the same thing, so too it is impossible for the
latter [‘all’ and ‘no’] to do so” (ὥσπερ ἐκεῖνα ἐν τῷ αὐτῷ ἀδύνατα εἶναι, οὕτω καὶ ταύτας).19 In other words, Gaius states
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stotelismus 553–556.
17 See Simplic. In Cat. 174.14 ff.
18 Albinus Didaskalikos 6.10, ed. P. Louis, Albinos. Epitomé (Paris 1945)
159.34–35; Anonymer Kommentar zu Platons Theaetet (Papyrus 9782), ed. J. L.
Heiberg (Berlin 1905) 68.10–49.
19 The vocabulary used by Italos is of a later period, as is confirmed by
the word συµψεύδονται, which occurs frequently only from Alexander of
Aphrodisias onwards. However, this is not relevant, I believe, for assessing
the authenticity of Italos’ report of Gaius’ view, since this is introduced by
the report of Ammonius’ and Porphyry’s views present in Ammonius’ commentary on De interpretatione, where in fact the word occurs at least six times
(100.13, 101.9, 146.10, 146.27, 234.4, 234.9) in the discussion of propositional theories. Thus we need not be surprised that Italos, influenced by
Ammonius, used late vocabulary in describing an earlier position. Furthermore, the terms συµψεύδεσθαι/συµψεύδονται also occur in a similar
context in the work of an author like Alexander of Aphrodisias, late second/
early third century, not so far removed from the second-century Middle
Platonists. For Alexander’s use of this term in general and in regard to the
positions of earlier philosophers on the theory of propositions, see his In
Aristotelis Analyticorum Priorum librum I commentarium, ed. M. Wallies (CAG II.1,
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A NEW TESTIMONY ON THE PLATONIST GAIUS
that propositions including terms such as ‘All’ and ‘No’ can
both be false about a certain subject, but cannot both be true
about that same subject; analogously, non-exhaustive contraries like ‘black’ and ‘white’ can both be false of a certain
subject, but cannot both be true of that same subject. At the
present stage of research, however, it remains difficult to develop this rather simple logical statement and venture that
Gaius shared the same metaphysical concern as other Middle
Platonists in referring Aristotle’s categories and logic generally
to the sensible world alone and not to the intelligible world.20
In conclusion, in spite of the difficulties in inferring Gaius’
doctrine from John Italos’ sketchy report, his treatise on De
interpretatione indicates that it is more than probable that in
eleventh-century Byzantium some additional information on
Gaius was available, directly or more likely indirectly in the
form of scholia in the margin of a logical text, possibly one of
the lost commentaries written by the Neoplatonists.21 It should
be remembered that eleventh-century Byzantines could still
read some ancient and late-antique material, in particular the
Platonic and Neoplatonic texts that were not lost until later.
The case of Michael Psellos, Italos’ master, who had access,
among many other works, to the now-lost Proclean commentary on Plotinus’ Enneads, is particularly telling in this regard.22
Accordingly, for the time being, I suggest that this Byzantine
witness should be included among those already known on the
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Berlin 1883) 418.5, and In Aristotelis Metaphysica commentaria, ed. M. Hayduck
(CAG I, Berlin 1891) 336.25–29.
20 See e.g. Moraux, Der Aristotelismus 592–601.
21 These are listed in Hasnaoui, La tradition 151–158.
22 See L.-G. Westerink, “Exzerpte aus Proklos’ Enneadenkommentar bei
Psellos,” BZ 52 (1959) 1–10. Another relevant case is that of the anonymous
commentary on Aristotle’s Categories, tentatively dated by its editors to the
third century A.D., discovered in the Archimedes palimpsest and probably
copied around the tenth century. On this see R. Chiaradonna, M. Rashed,
and D. Sedley (with N. Tchernetska), “A Rediscovered Categories Commentary,” Oxford Studies in Ancient Philosophy 44 (2013) 129–194.
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Middle Platonist Gaius. Scholars will then be in a position to
accept or reject its authenticity after a thorough examination of
its meaning and implications.23
September, 2013
University of Bari
Piazza Umberto I, 1
70121 Bari, Italy
miktrizio@gmail.com
23 I would like to express my gratitude to Mauro Bonazzi and David
Sedley for their careful reading and constructive suggestions concerning the
present paper and to Daniele Bianconi for a palaeographer’s view. I also
would like to thank Nikos Aghiotis for providing me with some further
material on the Byzantine commentary tradition on Aristotle’s De interpretatione.
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