In Ps.-Plutarch's epitome, Doctrines of the Philosophers (Plac.), lemma 4.11 bears the heading: Πῶς γίνεται ἡ αἴσθησις καὶ ἡ ἔννοια καὶ ὁ κατὰ ἐνδιάθεσιν λόγος (‘How sense perception, conception, and internal reason come to be’). The text reads:
(1) Οἱ Στωϊκοί ϕασιν· ὅταν γεννηθῇ ὁ ἄνθρωπος, ἔχει τὸ ἡγεμονικὸν μέρος τῆς ψυχῆς ὥσπερ χάρτην εὔεργον εἰς ἀπογραϕήν· εἰς τοῦτο μίαν ἑκάστην τῶν ἐννοιῶν ἐναπογράϕεται. (2) Πρῶτος δὲ [ὁ] τῆς ἀναγραϕῆς τρόπος ὁ διὰ τῶν αἰσθήσεων. αἰσθανόμενοι γάρ τινος οἷον λευκοῦ, ἀπελθόντος αὐτοῦ μνήμην ἔχουσιν· ὅταν δὲ ὁμοειδεῖς πολλαὶ μνῆμαι γένωνται, τότε ϕαμὲν ἔχειν ἐμπειρίαν· ἐμπειρία γάρ ἐστι τὸ τῶν ὁμοειδῶν ϕαντασιῶν πλῆθος. (3) Τῶν δὲ ἐννοιῶν αἱ μὲν ϕυσικῶς γίνονται κατὰ τοὺς εἰρημένους τρόπους καὶ ἀνεπιτεχνήτως, αἱ δὲ ἤδη δι’ ἡμετέρας διδασκαλίας καὶ ἐπιμελείας· αὗται μὲν οὖν ἔννοιαι καλοῦνται μόνον, ἐκεῖναι δὲ καὶ προλήψεις. (4) Ὁ δὲ λόγος, καθ’ ὅν προσαγορευόμεθα λογικοὶ ἐκ τῶν προλήψεων συμπληροῦσθαι λέγεται κατὰ τὴν πρώτην ἑβδομάδα.
(1) The Stoics say: When a human being has been born, the commanding part of his soul is like a sheet of paper in good condition for writing upon; upon this each one of his conceptions is written. (2) The first way of writing is through the senses. For when humans perceive something, e.g. something white, they have a memory of it when it goes away; and when many memories of the same kind have come to be, then we say that they have experience; for experience is a plurality of impressions of the same kind. (3) Of conceptions, some come about naturally and non-technically through the aforementioned ways, but others come about through our own learning and efforts. The latter are called ‘conceptions’, but the former are called ‘prolepses’ as well. (4) And reason, according to which we are called ‘rational’, is said to be completely filled out with prolepses at the age of seven years.Footnote 1
The plural ‘aforementioned ways’ in (3) has long troubled scholars because it does not have a clear antecedent in the preceding lines. ‘Through the senses’ is labelled as ‘the first way of writing’ in (2), but no additional ‘ways’ are labelled as such. This led Eduard Zeller to suggest that there may be a lacuna between πλῆθος at the end of (2) and τῶν δὲ ἐννοιῶν at the beginning of (3). He writes: ‘in context [“the aforementioned ways”] would mean “through memory and experience” – but perhaps the author of the Placita has excerpted badly here and the words originally indicated the various modes of concept-formation.’Footnote 2 Zeller's first suggestion – that ‘the aforementioned ways’ refers to memory and experience – is accepted by Hermann Diels.Footnote 3 But Adolf Bonhöffer rejects this reading as ‘highly unlikely’ on the grounds that memory and experience are subordinate stages of writing ‘through the senses’, rather than separate and coordinate ‘ways’ in their own right.Footnote 4 Instead, Bonhöffer further develops Zeller's second suggestion that between πλῆθος and τῶν δ’ ἐννοιῶν one or more sentences have fallen out. He conjectures that Ps.-Plutarch's source included a list of the various ways things are conceived similar to the one found at Diog. Laert. 7.52:
Τῶν γὰρ νοουμένων τὰ μὲν κατὰ περίπτωσιν ἐνοήθη, τὰ δὲ καθ’ ὁμοιότητα, τὰ δὲ κατ’ ἀναλογίαν, <τὰ δὲ κατὰ μετάθεσιν,> τὰ δὲ κατὰ σύνθεσιν, τὰ δὲ κατ’ ἐναντίωσιν.Footnote 5
Of the things that are conceived, some are conceived through direct experience, some through similarity, some through analogy, <some through transposition,> some through composition and some through opposition.
Bonhöffer suggests that ‘through direct experience’ in Diogenes' list corresponds to ‘through the senses’ in Ps.-Plutarch's account. Although he failed to copy out the rest of the list, Ps.-Plutarch retained the plural ‘aforementioned ways’ from his source when he summarized all of these modes of concept formation in (3). It is worth pausing for a moment to emphasize that the conjectured lacuna is not something that has fallen out of the manuscript tradition of Ps.-Plutarch's epitome. There are no variants listed by Diels, Mau or Lachenaud in their apparatus critici that would suggest this.Footnote 6 Rather, the conjecture is that Ps.-Plutarch's source contained an additional list of ways things are conceived that Ps.-Plutarch failed to copy. Zeller and Bonhöffer do not identify Ps.-Plutarch's source. If we accept Diels' hypothesis, however, Ps.-Plutarch's epitome was excerpted from the longer epitome of Aetius which seems to have been entitled simply On Doctrines (Περὶ ἀρεσκόντων).Footnote 7 Unfortunately, this section of Aetius' text is not attested in any of our other sources. If that work contained a longer list of the sort Bonhöffer imagines, Ps.-Plutarch's preservation of the plural ‘aforementioned ways’ is the only surviving evidence.
Bonhöffer's core argument is repeated with only minor variations by F.H. Sandbach, who is usually credited with the conjecture.Footnote 8 Sandbach adds that the conjectured supplement to Aetius' account is in accord with the Antiochean account offered by Cicero at Lucullus 30.Footnote 9 That text reads:
Mens enim ipsa, quae sensuum fons est atque etiam ipsa sensus est, naturalem vim habet, quam intendit ad ea, quibus movetur. Itaque alia visa sic adripit, ut iis statim utatur, alia quasi recondit, e quibus memoria oritur. Cetera autem similitudinibus construit, ex quibus efficiuntur notitiae rerum, quas Graeci tum ἔννοιας, tum προλήψεις vocant. Eo cum accessit ratio argumentique conclusio rerumque innumerabilium multitudo, tum et perceptio eorum omnium apparet et eadem ratio perfecta his gradibus ad sapientiam pervenit.
For the mind itself, which is the source of the senses and is itself also a sense, has a natural force that it directs to the things by which it is moved. Accordingly some presentations it seizes upon so as to make use of them at once, others it stores away, as it were, these being the source of memory, while all the rest it arranges by similarities, from which are formed the conceptions of things that the Greeks call sometimes “conceptions” and sometimes “prolepses.” When, to this reason, logical proof, and an innumerable multitude of facts have been added, then clear perception of all these things occurs and this same reason, having by these stages finally been made complete, attains wisdom.
I must admit that I fail to see Sandbach's point here. While there is a striking similarity between the stages of development in Cicero's account and in Ps.-Plutarch's text as we have it – note the progression in each from sense perception, to memory, conception, and finally reason – Cicero makes no mention of the ways things are said to be conceived in Diogenes' list at 7.52. If anything, the parallelism tells against the conjecture.Footnote 10
While Sandbach fails to advance the argument for the conjecture much further than Bonhöffer, his version of the conjecture occupies an important place in the literature. Sandbach concludes: ‘The two texts [i.e. Plac. 4.11.1–3 and Diog. Laert. 7.52–3] together give a perfectly consistent account of a preconception as the first conception of a thing, arrived at without special mental attention, and derived either directly or indirectly by some simple and unconscious mental operation from the data given by the senses.’ This summary has become the standard account of the Stoic doctrine of prolepsis in contemporary scholarship.Footnote 11
As for the conjecture itself, its subsequent history can be briefly summarized as follows. It is accepted by Max Pohlenz and Robert Todd, both of whom cite Sandbach. It is rejected by A.A. Long and David Sedley. And, most recently, it has been revived by Matthew Jackson-McCabe.Footnote 12 In these discussions two questions stand out. The first is whether the progression from sense perception to memory and experience in (2) should be viewed as three separate ‘ways’ of writing on the soul or whether we should think of this whole progression as constituting a single ‘way.’ If we take these as three separate ‘ways’, they are sufficient to explain Ps.-Plutarch's use of ‘the aforementioned ways’ at (3) and there is no need to conjecture a lacuna. This is the reading adopted by Diels and by Long and Sedley.Footnote 13 If, on the other hand, we follow Bonhöffer in reading memory and experience as subordinate to sense perception and therefore parts of the ‘first way’, then both Ps.-Plutarch's omission of any subsequent ‘ways’ and his use of ‘aforementioned ways’ require further explanation. This is the reading recently advocated by Jackson-McCabe, who writes: ‘Even if one could explain Aetius’ plural τρόπους entirely with reference to the description of the processes involved in acquisition διὰ τῶν αἰσθήσεων, this doesn't explain the introduction of the latter as πρῶτος ὁ τῆς ἀναγραϕῆς τρόπος.'Footnote 14
The second question is whether the list at Diog. Laert. 7.52 adds something that is doctrinally missing from Aetius' account of concept formation. Sandbach asserts that without a supplemental list of this kind Aetius would be committed to a statement of ‘obvious incompleteness.’Footnote 15 Long and Sedley, on the other hand, suggest that ‘much of D.L. 7.52–3 does not fit the scope of ἔννοιαι’.Footnote 16 To this argument Jackson-McCabe replies: ‘All of the examples given by Diogenes – with the possible exception of those acquired κατὰ μετάβασιν [“by transition”] – are in fact easily imagined as occurring “naturally” apart from the sort of intellectual effort required for conception in the strict sense.’Footnote 17
The proper way to answer both of these questions is to compare these two texts to similar accounts of concept formation in the Hellenistic period. Several scholars have noted that Aetius' account bears a striking similarity to Aristotle's developmental account of first principles at Posterior Analytics 99b34–110a9:Footnote 18
Ἐκ μὲν οὖν αἰσθήσεως γίνεται μνήμη, ὥσπερ λέγομεν, ἐκ δὲ μνήμης πολλάκις τοῦ αὐτοῦ γινομένης ἐμπειρία· αἱ γὰρ πολλαὶ μνῆμαι τῷ ἀριθμῷ ἐμπειρία μία ἐστίν. ἐκ δ’ ἐμπειρίας ἢ ἐκ παντὸς ἠρεμήσαντος τοῦ καθόλου ἐν τῇ ψυχῇ, τοῦ ἑνὸς παρὰ τὰ πολλά, ὃ ἂν ἐν ἅπασιν ἓν ἐνῇ ἐκείνοις τὸ αὐτό, τέχνης ἀρχὴ καὶ ἐπιστήμης, ἐὰν μὲν περὶ γένεσιν, τέχνης, ἐὰν δὲ περὶ τὸ ὄν, ἐπιστήμης.
Memory comes about from sense perception, as we say, and experience from the memory of the same thing coming to be many times; for the memories, which are many in number, constitute experience, which is one. From experience, or from the universal having made a stand in the soul – i.e. the one-over-many which is the same in each and every one of them – comes the principle of craft and knowledge – i.e. of craft concerning things coming to be and of knowledge concerning what is.
In Aristotle's account we see a nearly identical progression from sense perception to memory and experience. What comes from experience, according to Aristotle, is the universal or ‘one-over-many.’ In Aetius' account this is the level of conception. However, it is clear that in the Stoic account prolepses arise first among conceptions; and Chrysippus defines prolepsis as ‘the natural conception of universals’ (ἔστι δ’ ἡ πρόληψις ἔννοια ϕυσικὴ τῶν καθόλου, Diog. Laert. 7.54). Aristotle's final stage, craft and knowledge, corresponds roughly to the Stoics' technical conceptions (those that come about ‘through our own learning and efforts’), since craft and knowledge also come about through refinements and supplements to our natural conceptions of universals.Footnote 19
The verbal similarities between the two passages are so close that Sandbach suspects the Stoic account must have been influenced by Aristotle in some way.Footnote 20 The simplest explanation would be that the Stoics were familiar with An. post. 2.19. A second possibility, however, is that they were familiar with the similar account given at the beginning of the Metaphysics. At Met. 980a27–981a7 Aristotle writes:
Γίγνεται δ’ ἐκ τῆς μνήμης ἐμπειρία τοῖς ἀνθρώποις· αἱ γὰρ πολλαὶ μνῆμαι τοῦ αὐτοῦ πράγματος μιᾶς ἐμπειρίας δύναμιν ἀποτελοῦσιν … γίγνεται δὲ τέχνη ὅταν ἐκ πολλῶν τῆς ἐμπειρίας ἐννοημάτων μία καθόλου γένηται περὶ τῶν ὁμοίων ὑπόληψις.
In humans, experience comes about from memory; for many memories of the same thing produce the capacity for experience, which is singular. And craft comes to be when from the many notions of experience one universal judgment about the similar things has come to be.
A third possibility, proposed by Sandbach, is that the Stoics may have known Aristotle's Protrepticus, which seems to have contained a similar account.Footnote 21 A fourth possibility, which Sandbach does not consider, is that the Stoics were familiar with this doctrine from Theophrastus. We can observe the same basic progression from sense perception to memory, experience, conception and finally knowledge proper in the account attributed to Theophrastus at Sext.Emp. Math. 7.216–26. At Math. 7.224 in particular we are told that ‘the collection of similar phantasms of the intellect and the gathering of these phantasms of particulars under the single heading of the universal is called “conception”’(ἀλλ’ ὁ μὲν ἀθροισμὸς τῶν τοιούτων τοῦ νοῦ ϕαντασμάτων καὶ ἡ συγκεϕαλαίωσις τῶν ἐπὶ μέρους εἰς τὸ καθόλου ἔννοια καλεῖται). This passage links the Aristotelian universal directly to the Stoics' conception.Footnote 22
As one final point of comparison, we should set Ps.-Plutarch's text alongside the Antiochean account given by Cicero at Lucullus 30 (quoted above). Again, the progression of stages moves from simple sense perception to memory, experience (i.e. cetera similitudinibus construit), conception and finally knowledge proper. The most striking similarity between the texts is at the level of conception. Cicero notes the same ambiguity in Stoic terminology as Ps.-Plutarch: conceptions are sometimes called simply ‘conceptions’ and sometimes called ‘prolepses’ as well.
There are two salient points in these comparisons. The first is that none of these accounts interrupts the progression from sense perception to memory, experience and conception with a list of ways things are conceived similar to the one found at Diog. Laert. 7.52. If Aetius' original account did offer such a list, it would be entirely anomalous. The second is that the purpose of these texts is not to give a comprehensive account of the ways things are conceived. Rather, it is to explain how the higher functions of reason (i.e. conceptions of universals and knowledge proper) develop out of sense perception. This is the same purpose announced by the heading of Ps.-Plutarch's lemma; and this purpose is achieved without the conjectured supplement of a list of ways things are conceived similar to Diog. Laert. 7.52.
Let us now consider the family of texts to which the list at Diog. Laert. 7.52 belongs. A similar list occurs in Diogenes' account of Epicurean psychology (Diog. Laert. 10.32):
καὶ γὰρ καὶ ἐπίνοιαι πᾶσαι ἀπὸ τῶν αἰσθήσεων γεγόνασι κατά τε περίπτωσιν καὶ ἀναλογίαν καὶ ὁμοιότητα καὶ σύνθεσιν, συμβαλλομένου τι καὶ τοῦ λογισμοῦ.
All conceptions come to be from the senses through direct experience and analogy and similarity and composition, with reasoning making some contribution as well.
Epicurus' list includes four items that are also on the Stoic list: direct experience, analogy, similarity and composition. The Stoic list also includes two additional items: transposition and opposition. This may suggest that the Stoics adopted and expanded the Epicurean list. Diogenes' subsequent illustration of the Stoic list at 7.53 contains several more additions. He writes:
Κατὰ περίπτωσιν μὲν οὖν ἐνοήθη τὰ αἰσθητά· καθ’ ὁμοιότητα δὲ τὰ ἀπό τινος παρακειμένου, ὡς Σωκράτης ἀπὸ τῆς εἰκόνος· κατ’ ἀναλογίαν δὲ αὐξητικῶς μέν, <ὡς> ὁ Τιτυὸς καὶ Κύκλωψ· μειωτικῶς δέ, ὡς ὁ Πυγμαῖος. καὶ τὸ κέντρον δὲ τῆς γῆς κατ’ ἀναλογίαν ἐνοήθη ἀπὸ τῶν μικροτέρων σϕαιρῶν. κατὰ μετάθεσιν δέ, οἷον ὀϕθαλμοὶ ἐπὶ τοῦ στήθους· κατὰ σύνθεσιν δὲ ἐνοήθη Ἱπποκένταυρος· καὶ κατ’ ἐναντίωσιν θάνατος. νοεῖται δὲ καὶ κατὰ μετάβασίν τινα, ὡς τὰ λεκτὰ καὶ ὁ τόπος. ϕυσικῶς δὲ νοεῖται δίκαιόν τι καὶ ἀγαθόν· καὶ κατὰ στέρησιν, οἷον ἄχειρ.
Sensibles are conceived of through direct experience; things conceived of through something at hand are through similarity, e.g. Socrates from his image. Through analogy some are by expansion, e.g. Tityos and the Cyclops, and some are by diminution, e.g. the Pygmy. The centre of the earth is conceived of by analogy from smaller spheres. Through transposition, e.g. eyes in the chest; the Hippocentaur is conceived of through composition; and death through opposition. Again some things are conceived of through transference, e.g. the sayables and place. Something just and good is conceived of naturally; and through privation, e.g. [a man] without a hand.
Among the additions these illustrations make to the basic Stoic list at 7.52, expansion and diminution are clearly meant to be species of analogy.Footnote 23 Transference, natural conception and privation appear to be later additions.Footnote 24
At Fin. 3.33 Cicero writes:
cumque rerum notiones in animis fiant, si aut usu aliquid cognitum sit aut coniunctione aut similitudine aut collatione rationis, hoc quarto, quod extremum posui, boni notitia facta est.
Since conceptions of things come about in the mind when something is grasped either by direct experience or by conjunction or by similarity or by rational inference, the conception of the good comes to be in this fourth way which I have put last.
By ‘rational inference’ Cicero seems to mean ‘analogy.’Footnote 25 Thus, he only mentions the four ways included on the basic Epicurean list. However, in his subsequent discussion he denies that the good is conceived of by addition (accessione) or expansion (crescendo) or comparison (comparando), which suggests that he is familiar with subdivisions of analogy similar to the ones at Diog. Laert. 7.53.Footnote 26
Sextus cites a similar list of ways things come about in four passages: Math. 3.40–2, 8.56–60, 9.393–5 and 11.250–2. These lists vary slightly in their vocabulary and organization, but the most complete lists (at 3.40–2 and 9.393–5) include direct experience, similarity, analogy (with expansion and diminution as species), transposition, composition and transference. Elsewhere Sextus also mentions privation (3.51ff and 9.403ff.) and opposition (10.263–74). The most striking point of comparison is that in all four texts Sextus offers Socrates as the example of something conceived through similarity, the Cyclopes and Pygmy as examples of expansion and diminution, and the Hippocentaur as an example of composition – all four examples are used by Diogenes at 7.53. Thus, Sextus seems to be working from an expanded list similar to the one found in Diogenes. However, it may be significant that he does not attribute the list to any of the schools. He uses it indiscriminately against ‘the dogmatists’, a phrase that encompasses both Stoics and Epicureans.
The similarities between these texts strongly suggest that the core list of ways things are conceived reproduced at Diog. Laert. 7.52–3 was regarded as a standard unit in Hellenistic philosophy. The basic purpose of this list is to explain how the soul conceives of things that are not directly experienced on the basis of what is directly experienced. This is stated directly at Diog. Laert. 10.32 and most forcefully by Sextus (Math. 8.56–8):
Πᾶσα γὰρ νόησις ἀπὸ αἰσθήσεως γίνεται ἢ οὐ χωρὶς αἰσθήσεως, καὶ ἢ ἀπὸ περιπτώσεως ἢ οὐκ ἄνευ περιπτώσεως … καὶ καθόλου οὐδὲν ἔστιν εὑρεῖν κατ’ ἐπίνοιαν ὃ μὴ ἔχει τις αὑτῷ κατὰ περίπτωσιν ἐγνωσμένον. τοῦτο γὰρ ἢ κατὰ ὁμοιότητα τῶν ἐν περιπτώσει πεϕηνότων ληϕθήσεται ἢ κατὰ παραύξησιν ἢ κατὰ μείωσιν ἢ κατ’ ἐπισύνθεσιν.
Every thought comes to be from the senses or not without the senses, and either from direct experience or not without direct experience … and in general one can discover nothing at the level of conception that is not contained in what one knows by direct experience. For this will be grasped either by similarity to what is given in direct experience, or by expansion, or by diminution, or by composition.
It is not clear that the Stoics unanimously endorsed this empiricist project. In particular, the addition of ‘natural conception’ at Diog. Laert. 7.53 is sometimes thought to make room for ethical conceptions that develop from ‘internal principles’ rather than external perceptions.Footnote 27 But the Stoic list does share the basic intention of explaining how the soul comes to have conceptions of things that it cannot perceive directly, either because they do not exist (e.g. the Cyclops, Pygmy and Hippocentaur), or because they are incidentally imperceptible (e.g. Socrates and the centre of the earth), or because they are imperceptible by nature (e.g. λέκτα and place).
What is lacking from this second family of texts is any suggestion that conception requires a process of abstraction mediated by memory and experience – the very point emphasized by the texts that parallel Ps.-Plutarch 4.11.1–4. Bonhöffer suggests that things conceived of ‘by direct experience’ in Diogenes' account corresponds to conceptions written on the soul ‘through the senses’ in Aetius' account; and that memory and experience are subordinate modes of the latter.Footnote 28 But memory and experience are never mentioned in any of the texts that parallel Diog. Laert. 7.52–3. Rather, these texts assume that conceptions of sensibles are written directly upon the soul by the objects of perception.
In the accounts of universals given by Aristotle and Theophrastus, memory and experience are required to explain how the soul moves from perceptions of particulars to conceptions of the one-over-many. Specifically, memory and experience are required to bring together ‘the many presentations’ into a common pool from which the universal might be abstracted. Since this function is also implied in the Antiochean account at Lucullus 30, where Cicero says that conceptions are derived from the class of perceptions grouped by similarity, this is presumably the role of memory and experience at Plac. 4.11.1–4 as well. The family of texts to which Diog. Laert. 7.52–3 belongs does not share this concern with universal conceptions. The example of Socrates clearly shows that these texts include conceptions of individuals. Indeed, they seem to think of conceptions of individuals as being paradigmatic (e.g. the Cyclops, the Pygmy, the Hippocentaur); and none of the examples are unambiguously conceptions of universals.Footnote 29 Brittain (n. 12), 172–3 argues that the two texts assume two different senses of ‘to conceive of …’ (νοεῖν). In the family of texts to which Diog. Laert. 7.52–3 belongs ‘to conceive of …’ means ‘to think of …’ or ‘to imagine …’, whereas in the family of texts to which Plac. 4.11.1–4 belongs it means ‘to have a conception of …’. Comparison with Aristotle's and Theophrastus' accounts suggests that in Aetius' account ‘having a conception of something’ amounts to grasping the universal or one-over-many. This is confirmed by Chrysippus' definition of prolepsis as ‘the natural conception of universals’ (Diog. Laert. 7.54).Footnote 30
In conclusion, according to the Bonhöffer–Sandbach conjecture, the Aetian source for Plac. 4.11.1–4 contained something like the following list of ways that conceptions are written upon the soul:
(1) through the senses via memory and experience,
(2) through similarity,
(3) through analogy,
(4) through composition,
(5) through transposition,
(6) through opposition.
Aetius reproduced only (1), but retained the summary statement – ‘the aforementioned ways’ – referring to (1) through (6). However, we do not find this kind of hybrid list in any other texts on concept formation in Hellenistic philosophy. Rather, we find that accounts of concept formation fall into two distinct families. The first family of texts explains how conceptions of universals develop out of sense perception through a process of abstraction involving memory and experience. The second explains how conceptions of things that are not directly perceived developed through various processes of association working on the materials provided by sense perception. The account as we have it, without any conjectured lacuna, clearly falls within the first family. While Ps.-Plutarch's introduction of sense perception as ‘the first way’ and subsequent summary of sense perception, memory and experience as ‘the aforementioned ways’ is admittedly awkward, this seems to be the best reading of the text.
Mansfeld and Runia's analysis of Ps.-Plutarch's process of abridgement provides final confirmation of this reading.Footnote 31 They note that Ps.-Plutarch never paraphrases his material from Aetius: he only transcribes or excises. His most common method is to leave out entire lemmata. They find only two examples – lemmata 1.29.2 and 2.13.4 – where Ps.-Plutarch leaves out material from the middle of a lemma.
Two important corollaries can be derived from this conclusion. The first is that there is no reason to think that Diog. Laert. 7.52–3 describes the ways that prolepses come about, as is often assumed. Long and Sedley reject this common interpretation on the grounds that ‘much of D.L. 7.53 does not fit the scope of ἔννοιαι’.Footnote 32 When Jackson-McCabe replies that the examples given by Diogenes are best thought of ‘as occurring “naturally” apart from the sort of intellectual effort required for conception in the strict sense’, he misses the point of Long and Sedley's objection.Footnote 33 Conceptions, of which prolepses are a species in Ps.-Plutarch's account, are universal conceptions; but many of the conceptions at Diog. Laert. 7.53 are not. Indeed, not everything that is conceived of spontaneously in the broader sense of νοεῖν meaning ‘thought of’ or ‘imagined’ will be a prolepsis. This is the second corollary to be drawn from placing Aetius' account in its proper context. Only conceptions of universals that are naturally generated through abstraction from sense perception via memory and experience – i.e. according to the process described in the first family of texts – are prolepses. This is what Chrysippus means when he defines prolepsis as ‘the natural conception of universals’. Recognizing that the Stoic doctrine of prolepsis belongs to the first family of texts places the doctrine into its appropriate comparative context.
