Epistemological debates during the Hellenistic period centred on the question of how knowledge is possible or, put differently, of whether there are criteria of truth (κριτήρια τῆς ἀληθείας), that is, entities that can guarantee the existence of knowledge in the first place.Footnote 1 As is well known, Epicurus is to have claimed in his now-lost work Kanon (Yard Stick) that there are three such criteria: perceptions (αἰσθήσεις), feelings (πάθη) and preconceptions (προλήψεις).Footnote 2 And as Diogenes Laertius, the source for the comment, goes on to explain, ‘(later) Epicureans also (add) τὰς φανταστικὰς ἐπιβολὰς τῆς διανοίας’ (10.31 = fr. 35 Usener). This claim gains some additional plausibility by a fragment from On Methods of Inference, which, if restored correctly, would show that the later Epicurean Philodemus included ἐπιβολαὶ τῆς διανοίας among the criteria of truth.Footnote 3 Be that as it may, what are ἐπιβολαὶ τῆς διανοίας? This will be the topic of this paper, which will shed light on the fourth Epicurean criterion of truth: what it is, what role it may have played in Epicurean epistemology and why it may have been elevated to criterial status by later Epicureans.Footnote 4
In the first section of the paper, I will survey different usages of the term ἐπιβολή in Epicurus. I will argue that, in addition to a general sense of mental act (‘thought’) and of mental act that accompanies an act of perception (‘act of attention’), Epicurus assumes that ἐπιβολαὶ τῆς διανοίας are mental perceptions, the prime example of which is the perception of the gods in dreams. The second section of this paper will then be dedicated to ἐπιβολαὶ τῆς διανοίας as a criterion of truth. After outlining some features that an ἐπιβολή must have in order to be a criterion on par with the other criteria that Epicurus distinguishes, I will argue that ἐπιβολή in the third sense that I distinguished (‘mental perception’) is the most plausible sense in which ἐπιβολή can be understood as a criterion. The third section then compares ἐπιβολή to preconceptions, to which they have been likened, following a comment in Clement of Alexandria. I will discuss different ways in which ἐπιβολαί can be thought to be similar to preconceptions, but I will ultimately argue that they should not be identified with them. In the fourth section, I will finally turn to the textual evidence on ἐπιβολή (or its Latin equivalent) in later authors (Cicero, Lucretius and Philodemus). Although there is some evidence that later Epicurean authors developed the conception of ἐπιβολή further, understanding it as a kind of grasp or direct intuition of what is traditionally thought to be only accessible by a rational inference, I will argue that this new sense of ἐπιβολή is not the one in which later Epicureans elevate ἐπιβολαί to the status of a criterion of truth.
1. THREE SENSES OF ΕΠΙΒΟΛΗ IN EPICURUS
Let us begin with the etymology of the term ἐπιβολή. The term is derived from the verb ἐπιβάλλω, which means ‘to cast or throw upon’ or, alternatively, ‘to apply’. διάνοια means ‘mind’ or ‘thought’.Footnote 5 Accordingly, ἐπιβολὴ τῆς διανοίας can be translated as ‘application of the mind’. Alternative English translations include ‘focussing of the mind’, ‘apprehension of the mind’, ‘contact of the mind’ and ‘attending of the mind’. All of these translations get at the same idea: that ἐπιβολαὶ τῆς διανοίας consist in some mental act, the precise nature and purpose of which is to be elucidated in what follows.
The term ἐπιβολή is mentioned ten times in the Letter to Herodotus Footnote 6 as well as once in Kuria Doxa 24. In addition, it is mentioned in Epicurus’ On Nature Footnote 7 as well as in the passage in Diogenes’ life of Epicurus (already discussed above) and in Clement's Stromata (2.4 = fr. 255 Usener). In what follows, I will survey these passages and argue that we can distinguish three usages of the term: (1) ‘thought in general’, (2) ‘act of attention’ and (3) ‘mental perception’.
An ἐπιβολή can refer to a thought whose object can have varying degrees of generality. Accordingly, Epicurus notes at Letter to Herodotus 35 that ‘we frequently need the overall application (of the mind), not so often the detailed one’ (τῆς … ἀθρόας ἐπιβολῆς πυκνὸν δεόμεθα, τῆς δὲ κατὰ μέρος οὐχ ὁμοίως).Footnote 8 Epicurus also mentions a kind of ‘peculiar’ ἐπιβολή, that is, an act of thinking that is proper to a specific object, in his discussion of bodies and properties: ‘But all of these (are known) by their own peculiar forms of application and comprehension, always in close accompaniment with the aggregate and in no way separate from it, which is given the predicate “body” by reference to the aggregate conception’ (καὶ ἐπιβολὰς μὲν ἔχοντα ἰδίας πάντα ταῦτά ἐστι καὶ διαλήψεις, συμπαρακολουθοῦντος δὲ τοῦ ἀθρόου καὶ οὐθαμῇ ἀποσχιζομένου, ἀλλὰ κατὰ τὴν ἀθρόαν ἔννοιαν τοῦ σώματος κατηγορίαν εἰληφότος, Ep. Hdt. 69; see also 70). By contrast, in the following passage, in the beginning of the Letter to Herodotus, Epicurus makes clear that there are certain thoughts about general ideas pertaining to Epicurean doctrine that would be beneficial to every student of Epicureanism to master (Ep. Hdt. 36; see also 83):
βαδιστέον μὲν οὖν καὶ ἐπ᾽ ἐκεῖνα συνεχῶς, ἐν <δὲ> τῇ μνήμῃ τὸ τοσοῦτο ποιητέον, ἀφ᾽ οὗ ἥ τε κυριωτάτη ἐπιβολὴ ἐπὶ τὰ πράγματα ἔσται καὶ δὴ καὶ τὸ κατὰ μέρος ἀκρίβωμα πᾶν ἐξευρήσεται, τῶν ὁλοσχερωτάτων τύπων εὖ περιειλημμένων καὶ μνημονευομένων⋅ ἐπεὶ καὶ τῷ τετελεσιουργημένῳ τοῦτο κυριώτατον τοῦ παντὸς ἀκριβώματος γίνεται, τὸ ταῖς ἐπιβολαῖς ὀξέως δύνασθαι χρῆσθαι καὶ <τοῦτο ἀδύνατον μὴ πάντων> πρὸς ἁπλᾶ στοιχειώματα καὶ φωνὰς συναγομένων.
We must, then, approach those (general points) continually, and get into our memory an amount (of doctrine) sufficient to permit the most vital application to the facts. Moreover, complete precision on detailed points will be discovered if the general outlines are comprehensively grasped and remembered. For even the fully expert (student of physics) gets the most vital benefit of complete precision the nimble ability to make use of his applications, and <this would happen if every point> were united in (a set of) principles and maxims.
The passage just quoted also makes clear that there is some connection between ἐπιβολαί and memory (μνήμη). In this sense ἐπιβολή in some way helps the recall of objects that were previously committed to memory, in this case, the principal maxims of Epicureanism, or it simply is a kind of mental act that makes it possible to conjure up something that is not immediately present in the mind.Footnote 9
In addition to a kind of thought broadly understood, Epicurus, second, uses the term ἐπιβολή in the sense of a mental act that accompanies another act, for instance a sense perception. He distinguishes between ἐπιβολαί that are associated with the sense organs (τὰ αἰσθητήρια) and those associated with the mind (διάνοια). Discussing perception at Letter to Herodotus 50, Epicurus observes:
καὶ ἣν ἂν λάβωμεν φαντασίαν ἐπιβλητικῶς τῇ διανοίᾳ ἢ τοῖς αἰσθητηρίοις εἴτε μορφῆς εἴτε συμβεβηκότων, μορφή ἐστιν αὕτη τοῦ στερεμνίου, γινομένη κατὰ τὸ ἑξῆς πύκνωμα ἢ ἐγκατάλειμμα τοῦ εἰδώλου. τὸ δὲ ψεῦδος καὶ τὸ διημαρτημένον ἐν τῷ προσδοξαζομένῳ ἀεί ἐστιν <ἐπὶ τοῦ προσμένοντος> ἐπιμαρτυρηθήσεσθαι ἢ μὴ ἀντιμαρτυρηθήσεσθαι, εἶτ᾽ οὐκ ἐπιμαρτυρουμένου <ἢ ἀντιμαρτυρουμένου>.
And whatever presentation we receive by a form of application, whether by the mind or by the sense organs, and whether of a shape or of accidents, this is the shape of the solid object, produced by the continuous compacting or residue of the image. Falsehood or error always resides in the added opinion <in the case of something which awaits> testimony for or against it but in the event receives neither supporting testimony <nor opposing testimony>.
In this passage, ἐπιβολαί are understood as accompanying mental acts. In the case of sense perception, perceivers do not only receive a constant stream of images that all bodies of the phenomenal world emit on the Epicurean view that then lead to the formation of a presentation, but there is also a mental act that accompanies this process. Scholars have described such an accompanying mental act as an act of attention or focussing.Footnote 10 Perceivers receive so many images that it is impossible to process them all at once. Accordingly, they must focus on something. There thus seems to be something ‘active’ about the act perception,Footnote 11 and to guarantee such an ‘active’ function of perception is the role of ἐπιβολαί.
Again, then, in the case of sense perception, the focus on particular objects of perception is called an ‘application of the sense organs’ (ἐπιβολὴ τῶν αἰσθητηρίων). By contrast, an ἐπιβολὴ τῆς διανοίας has to accompany a non-sensory act of perception, a kind of perception distinct from the perception of the five senses: a kind of ‘mental perception’, a perception that uses the mind as a kind of sense organ.Footnote 12 That there is such a mental perception is clear at Letter to Herodotus 49, immediately before the passage just discussed, where the case of mental vision is treated analogously to bodily vision:
δεῖ δὲ καὶ νομίζειν ἐπεισιόντος τινὸς ἀπὸ τῶν ἔξωθεν τὰς μορφὰς ὁρᾶν ἡμᾶς καὶ διανοεῖσθαι· οὐ γὰρ ἂν ἐναποσφραγίσαιτο τὰ ἔξω τὴν ἑαυτῶν φύσιν τοῦ τε χρώματος καὶ τῆς μορφῆς διὰ τοῦ ἀέρος τοῦ μεταξὺ ἡμῶν τε κἀκείνων, οὐδὲ διὰ τῶν ἀκτίνων ἢ ὧν δήποτε ῥευμάτων ἀφ' ἡμῶν πρὸς ἐκεῖνα παραγινομένων, οὕτως ὡς τύπων τινῶν ἐπεισιόντων ἡμῖν ἀπὸ τῶν πραγμάτων ὁμοχρόων τε καὶ ὁμοιομόρφων κατὰ τὸ ἐναρμόττον μέγεθος εἰς τὴν ὄψιν ἢ τὴν διάνοιαν, ὠκέως ταῖς φοραῖς χρωμένων.
One must also believe that it is when something from the external objects enters into us that we see and think about their shapes. For external objects would not stamp into us the nature of their own colour and shape via the air which is between us and them, nor via the rays or any kind of flows which move from us to them, as well as (they would) by means of certain outlines which share the colour and shape of the objects and enter into us from them, entering the vision or the intellect according to the size and fit (of the effluences) and moving very quickly.
The passage does not spell out what this mental perception is of, but the prime candidate for it is the perception of the gods. On the Epicurean view, perceivers receive images of the gods in dreams, even if the term ἐπιβολή is never used with regard to the mental perception of the gods.Footnote 13 In addition to this, centaurs, unicorns and other kinds of chimeras, which do not have a real-world referent (except for the images that have randomly become entangled somewhere in space), are also said to be perceived only by the mind, making these perceptions another candidate for mental perceptions. On this second understanding of ἐπιβολὴ τῆς διανοίας, then, ἐπιβολαὶ τῆς διανοίας would be the acts of attention that accompany the perception of the gods or chimeras, which contrasts with the acts of attention that accompany the perception of the senses.
Such a reading is overall in line with Letter to Herodotus 51, a passage in which different kinds of ἐπιβολαί are contrasted:
ἥ τε γὰρ ὁμοιότης τῶν φαντασμῶν οἱονεὶ ἐν εἰκόνι λαμβανομένων ἢ καθ᾽ ὕπνους γινομένων ἢ κατ᾽ ἄλλας τινὰς ἐπιβολὰς τῆς διανοίας ἢ τῶν λοιπῶν κριτηρίων οὐκ ἄν ποτε ὑπῆρχε τοῖς οὖσί τε καὶ ἀληθέσι προσαγορευομένοις, εἰ μὴ ἦν τινα καὶ ταῦτα πρὸς ἃ <ἐπι>βάλλομεν· τὸ δὲ διημαρτημένον οὐκ ἂν ὑπῆρχεν, εἰ μὴ ἐλαμβάνομεν καὶ ἄλλην τινὰ κίνησιν ἐν ἡμῖν αὐτοῖς συνημμένην μὲν <τῇ φανταστικῇ ἐπιβολῇ>, διάληψιν δὲ ἔχουσαν· κατὰ δὲ ταύτην, ἐὰν μὲν μὴ ἐπιμαρτυρηθῇ ἢ ἀντιμαρτυρηθῇ, τὸ ψεῦδος γίνεται· ἐὰν δὲ ἐπιμαρτυρηθῇ ἢ μὴ ἀντιμαρτυρηθῇ, τὸ ἀληθές.
For the similarity of appearances (which are like what are grasped in a representational picture and occur either in dreams or in some other application of the mind or the other criteria) to what are called real and true things would never occur if some such thing were not added (to the basic experience). And error would not occur if we did not have some other motion in ourselves which is linked <to the presentation-producing application> but is distinct;Footnote 14 falsehood, which occurs because of this, if it is not testified for or testified against; but if it is testified for or is not testified against, truth occurs.
The passage claims that dreams are one source of appearances (φαντάσματα) and suggests that they are one of the species of the genus ἐπιβολὴ τῆς διανοίας, which are again said to be distinct from the other criteria, which presumably mainly means perception: the five other senses.Footnote 15 This makes ἐπιβολή into a kind of sixth sense, a kind of mental perception. Note here, though, that Letter to Herodotus 51 takes ἐπιβολὴ τῆς διανοίας not as the mental act that accompanies a mental perception, as the previous passage did, but as the mental perception itself. This runs together the distinction that was just drawn (or alternatively points to a slightly different structure of mental and sensual perceptions) and gives rise to the third sense of ἐπιβολὴ τῆς διανοίας: a mental perception.Footnote 16
This third sense of ἐπιβολή is also found in an important passage of On Nature 34, which among other topics, discusses mental perception. The text has unfortunately come down to us in only a very fragmentary state. Epicurus claims here that ἐπιβολαί are a means of coming to know what is otherwise invisible: ‘so that also we see all natures that (derive) from applications [of the mind] that immediately proceed to the invisible if we look at the likenesses’ (ὥστε καὶ [π]ά[σας φ]ύσεις τὰς [ἐ]κ [τῶν ἐπι]βολῶν [τῶν ἐπὶ τ]ὸ ἀόρατον ἥδ[η βαδ]ιζουσῶν ὀ[ψ]όμ[ε]θ᾽ ἂ[ν] εἰς ὁμοιό[τ]ητα[ς] ἰδῶμεν, P.Herc. 1431, col. XI.1–7 Leone; transl. mine).
Before moving on to discussing ἐπιβολὴ τῆς διανοίας as a criterion, we should note that in some passages the term φανταστική is added to ἐπιβολή as, for instance, in RS 24:
εἴ τιν᾽ ἐκβαλεῖς ἁπλῶς αἴσθησιν καὶ μὴ διαιρήσεις τὸ δοξαζόμενον καὶ τὸ προσμένον καὶ τὸ παρὸν ἤδη κατὰ τὴν αἴσθησιν καὶ τὰ πάθη καὶ πᾶσαν φανταστικὴν ἐπιβολὴν τῆς διανοίας, συνταράξεις καὶ τὰς λοιπὰς αἰσθήσεις τῇ ματαίῳ δόξῃ, ὥστε τὸ κριτήριον ἅπαν ἐκβαλεῖς. εἰ δὲ βεβαιώσεις καὶ τὸ προσμένον ἅπαν ἐν ταῖς δοξαστικαῖς ἐννοίαις καὶ τὸ μὴ τὴν ἐπιμαρτύρησιν <ἔχον>, οὐκ ἐκλείψεις τὸ διεψευσμένον, ὡς τετηρηκὼς ἔσῃ πᾶσαν ἀμφισβήτησιν κατὰ πᾶσαν κρίσιν τοῦ ὀρθῶς ἢ μὴ ὀρθῶς.
If you reject unqualifiedly any sense perception and do not distinguish the opinion and what awaits confirmation and what is already present in the sense perception and the feelings and every presentational application of the mind, you will also disturb the rest of your sense perceptions with your pointless opinion with the result that you will reject every criterion. If, on the other hand, you affirm both everything that awaits confirmation in your conceptions formed by opinion and what is not testified for, you will not avoid falsehood, so that you will be in the position of maintaining every disputable point in every decision about what is correct and not correct.
What does φανταστική mean? Some commentators have proposed that the function of the term φανταστική is to rule out mental acts that have as their objects illusory entities such as centaurs, which are perceived only by the mind after images randomly become intertwined in space, since such mental acts do not refer to an object that truly exists.Footnote 17 However, in so far as such images are not merely optical illusions, but truly directly enter the mind, it is unclear why such presentations ought to be treated differently than optical illusions.Footnote 18 Epicurus maintains that all perceptions are true. This includes perceptions of optical illusions such as the stick partially submerged in water that appears bent (which will be discussed in more detail shortly) and even perceptions of people who are mentally ill.Footnote 19 Therefore, it seems prima facie surprising that Epicurus would not also make the same claim about mental perceptions, namely that the perception itself is true, but that error is introduced by the mind in some other way. In absence of further textual evidence, it is, therefore, most plausible to understand ‘presentation-producing’ or ‘presentational’ (φανταστική) applications of the mind as those presentations that are not general thoughts that merely recall what a perceiver has previously experienced, but rather as those applications that yield knowledge of objects that are not traditionally grasped by sense perception such as the gods.Footnote 20
2. ΕΠΙΒΟΛΗ ΤΗΣ ΔΙΑΝΟΙΑΣ ΑS A CRITERION OF TRUTH
Having distinguished between three senses of ἐπιβολή in the previous section, we can now turn to how ἐπιβολαί can be understood as criteria of truth. As such, ἐπιβολαί τῆς διανοίας must always be true, just as perceptions, feelings and preconceptions. As Letter to Herodotus 50–1 makes clear, error on the Epicurean view is introduced at the level of opinion. This means that ἐπιβολὴ τῆς διανοίας itself does not contain any errors.Footnote 21 On the Epicurean view, falsehood comes to be by an intervention of the mind, which adds or subtracts something from a presentation, thereby falsifying it.Footnote 22 For instance, in the case of the well-known optical illusion of the straight stick partially submerged in water that appears bent, Epicurus maintains that the eyes correctly report that the stick is bent, but that, in forming the opinion that the stick is actually bent, the mind errs in forming the conclusion.Footnote 23 Likewise, then, Letter to Herodotus 51 is clear in claiming that falsehood is associated with a movement that is connected to an ἐπιβολὴ τῆς διανοίας, but that ἐπιβολὴ τῆς διανοίας is not identical with this movement.Footnote 24
Furthermore, since ἐπιβολὴ τῆς διανοίας as a criterion is free from falsehood, it must be a non-inferential source of knowledge. By this I mean that ἐπιβολὴ τῆς διανοίας does not require higher-level reasoning to come about.Footnote 25 There is no evidence that requires us to assume that the mind draws an inference of any kind when having an ἐπιβολὴ τῆς διανοίας or again that the mind adds or subtracts anything when having an ἐπιβολὴ τῆς διανοίας. A direct consequence of this is that we can restrict the third sense of ἐπιβολαὶ τῆς διανοίας, that is, of mental perception, to exclude entities that are ἄδηλα (non-evident) such as atoms, the void and the all, because these entities can only be grasped through a more complex pattern of inference that is usually referred to as ‘not testifying against’ (οὐκ ἀντιμαρτύρησις).Footnote 26 Likewise, such a reading rules out that such ἐπιβολαί are of scientific concepts,Footnote 27 because such scientific concepts would most certainly be the result of some inference that cannot be characteristic of ἐπιβολαὶ τῆς διανοίας.
Furthermore, with regard to the second sense of ἐπιβολαί as an act of attention, I noted that an act of attention typically requires the mind to be ‘active’. This claim can now be specified. If ἐπιβολαί are a kind of mental focussing, this focus cannot entail that the mind processes the information that it receives by drawing inferences from it.Footnote 28 After all, this is not true of any criterion. For instance, Voula Tsouna has rightly argued for what she calls a ‘Lockean’ reading of preconceptions, according to which preconceptions are formed without the intervention of the mind,Footnote 29 and perceptions, according to Epicurus, are ἄλογος,Footnote 30 that is, free from the interventions of the mind in any substantive way.Footnote 31
Having specified the meaning of two senses of ἐπιβολή in light of their potential criterial nature, we can next turn to the following question: in which of these three senses are ἐπιβολαί most likely criteria of truth? The understanding of ἐπιβολή in the first sense (generic mental acts) is too broad to be a meaningful guarantor of truth. This is especially true in so far as the example of such ἐπιβολαί are ἐπιβολαί about doctrines. Doctrines are (true) opinions, which are learned through inferences on the Epicurean view; they are not immediately grasped by intuitions. To put the same point differently, other criteria either directly refer to and report on the truth of an object or alternatively are conceptual devices that help categorize objects. It is thus hard to see how generic thoughts would be a meaningful addition to Epicurean epistemology rather than completely destroy its empirical foundations.
Second, the suggestion that ἐπιβολαί as criteria are acts of attention runs into a different challenge.Footnote 32 It is unclear why merely an accompanying mental act should guarantee the truth of a sense perception, if the sense perception itself is already, as a criterion of truth, a guarantor of truth. If an ἐπιβολή is only an accompanying act, it is superfluous and does not add anything to the sense perception. The same objection also holds with regard to the other criteria of truth, that is, feelings and preconceptions: it is unclear how an act of attention as an additional criterion of truth does not diminish their value as criteria.
This then leads us to the third and last understanding of ἐπιβολαί distinguished above: mental perceptions. Understanding ἐπιβολαὶ τῆς διανοίας in this way furnishes a neat understanding why later Epicureans may have elevated them to a criterial status.Footnote 33 Since mental perception might be said to be a source of knowledge for the Epicureans, just as sense perceptions and feelings, so ἐπιβολαί, understood in this way, would complement the perception of the world that is embodied by these two other criteria just mentioned. The reading gains additional plausibility by the fact that Letter to Herodotus 51, for instance, already uses ἐπιβολή in a criterial sense, even if the term ‘criterion’ is not explicitly used. Furthermore, it is easy to understand on this reading why Epicurus himself may have not yet elevated ἐπιβολαί to criterial status, as later Epicureans seem to have done. Since the existence of mental perception is somewhat in tension with what is otherwise an empiricist epistemology, Epicurus may have been keen to downplay the impression that he was not in any way an empiricist.Footnote 34 In other words, it is unnecessary to assume that the question to include Epicurean ἐπιβολαί among the criteria of truth is in any way indicative of a more substantial disagreement between the school founder and his followers.
3. ΕΠΙΒΟΛΗ AND PRECONCEPTIONS
After this preliminary sketch, one may wonder how ἐπιβολὴ τῆς διανοίας relates to preconceptions. After all, Clement of Alexandria reports that, on the Epicurean view, preconceptions are ἐπιβολαί: ‘(Epicurus) defines a preconception as an ἐπιβολή with regard to something manifest (ἐναργής) and with regard to a manifest concept of the thing.’Footnote 35
It would exceed the scope of this paper to give a full account of preconceptions in Epicureanism, so I will have to restrict myself to some key observations. First, despite what prima facie seems to be evidence to the contrary, it is now generally assumed that preconceptions are not innate ideas, but rather come to be empirically, as a result of multiple perceptions.Footnote 36 Accordingly, aetiologically, preconceptions differ from perceptions and feelings in so far as the former take time to be formed, whereas the access to the latter is immediate.Footnote 37 If preconceptions are ἐπιβολαὶ τῆς διανοίας, it would well explain some important passages, for instance RS 24 (quoted above): ‘If you reject unqualifiedly any sense perception and do not distinguish the opinion about what awaits confirmation, and what is already present in the sense perception and the feelings and every presentational application of the mind (φανταστικὴν ἐπιβολὴν τῆς διανοίας), you will also disturb the rest of your sense perceptions with your pointless opinion with the result that you will reject every criterion.’ The reason is that, if one assumes that preconceptions are identical with ἐπιβολαὶ τῆς διανοίας, RS 24 would speak of the three standard criteria of truth (perceptions, feelings and preconceptions). Likewise, such a reading would emphasize yet another dimension of ἐπιβολαὶ τῆς διανοίας, namely that they refer not only to the movement of thought that accompanies a mental perception and the mental perception itself but also to the content of the mental perception, that is, perhaps a kind of concept.Footnote 38 One can see this at Letter to Herodotus 38, where ἐπιβολὴ τῆς διανοίας refers to a kind of mental content, not to an act or process:
εἶτα κατὰ τὰς αἰσθήσεις δεῖ πάντα τηρεῖν καὶ ἁπλῶς τὰς παρούσας ἐπιβολὰς εἴτε διανοίας εἴθ᾽ ὅτου δήποτε τῶν κριτηρίων, ὁμοίως δὲ καὶ τὰ ὑπάρχοντα πάθη, ὅπως ἂν καὶ τὸ προσμένον καὶ τὸ ἄδηλον ἔχωμεν οἷς σημειωσόμεθα, ταῦτα δὲ διαλαβόντας συνορᾶν ἤδη περὶ τῶν ἀδήλων.
Again, it is also necessary to observe all things in accordance with one's sense perceptions, that is, simply according to the present applications, whether of the mind or any of the other criteria, and similarly (to observe everything) in accordance with our actual feelings, so that we can have some sign by which we may make inferences both about what awaits confirmation and about the non-evident.
Understood as a kind of concept, then, an ἐπιβολὴ τῆς διανοίας seems to be very close to a preconception.Footnote 39
However, there are also important reasons to be sceptical of identifying preconceptions and ἐπιβολή. Clement's report is the only passage in which a preconception is called an ἐπιβολή, and we cannot be sure that the words used are really Epicurus’ own.Footnote 40 As we saw above, other passages in the Epicurean corpus distinguish ἐπιβολαὶ τῆς διανοίας and preconceptions as separate entities. Accordingly, an identification of the two technical terms is prima facie suspicious. This is all the more the case in so far as, etymologically, the two terms identify quite different activities. An ἐπιβολή is an application or ‘throwing out’ of the mind, whereas a πρόληψις designates a ‘prior grasp’ or ‘receiving’.Footnote 41
Furthermore, even if the words used in Clement are Epicurus’ own, one might also argue that in the passage in Clement ἐπιβολή is used in a general sense, as a generic term for thought. This was the first usage of the term ἐπιβολή that I distinguished in the first section of this paper. However, as I argued above, this sense of ἐπιβολή is not the one in which ἐπιβολή can most plausibly be taken to be a criterion of truth. Accordingly, the claim that a preconception is an ἐπιβολή understood as a general thought is compatible with the claim that there are ἐπιβολαί as criteria of truth that are distinct from the entities that Clement is referring to in the above passage.
Finally, the two passages that were quoted above, RS 24 and Letter to Herodotus 38, are perfectly intelligible if preconceptions and ἐπιβολαί are not identified. Since all mental acts have a content, ἐπιβολή in the passage from the Letter to Herodotus may simply be a shorthand to refer to mental content (according to the general reading of the term just proposed). In regard to RS 24, while it seems desirable to offer a simple and straightforward reading of the Epicurean criteria of truth, the passage in Diogenes Laertius, with which the paper began, already makes clear that there may have been some development of Epicurean doctrines, even if it may be difficult to reconstruct the exact chronology of this development.Footnote 42 In any case, simply substituting preconceptions for ἐπιβολαί in that text may oversimplify the complex evolution of Epicurean doctrines.
Yet, even if we can easily explain the passage in Clement, which seems to speak of an ἐπιβολή as a kind of concept simpliciter and in this way similar to a preconception, one might also think that an ἐπιβολή is a kind of active movement or active part of a kind of generic mental perception.Footnote 43 Such a reading would help explain how a thought can become an immediately true criterion, on the Epicurean view, namely, like perception, through the presentations it processes. However, Voula Tsouna has recently argued against such an assimilation of ἐπιβολὴ τῆς διανοίας and the active part of a preconception.Footnote 44 With regard to the requirement that all criteria of truth should be immediately true and evident, Tsouna observes that preconceptions fulfil this requirement because of their connection to perception as well as because they are immediately available to further thinking. Accordingly, there is no need for ἐπιβολή understood as an additional active movement of the mind to make preconceptions into a criterion of truth. Furthermore, Tsouna also rightly questions the kind of immediacy we can reasonably expect from preconceptions in Epicureanism, given that their role in epistemology differs from that of feelings and sense perceptions: while feelings and sense perceptions are immediate by referring to experience, preconceptions are immediate with regard to more complex states of affairs.Footnote 45
The results of this section are thus the following. ἐπιβολαί are not to be identified with preconceptions simpliciter; they are separate and so are a criterion separate from preconceptions. By contrast, I argued in the second section of the paper that the most plausible way of interpreting ἐπιβολαί as criterion is to understand them as kinds of mental perception, as in dreams and imagination, and of some objects that are otherwise not observable with the senses. In short, then, there should be ἐπιβολαὶ τῆς διανοίας, direct mental perceptions, of the gods, for instance, as well as a preconception of them that follows as a result of these mental perceptions.Footnote 46
As we saw at the beginning, later Epicureans are supposed to have elevated ἐπιβολή to criterial status. In the next and last section of the paper, I will, therefore, consider how the reading of ἐπιβολή as criterion suggested here holds up against the textual evidence in later Epicurean authors.Footnote 47
4. ΕΠΙΒΟΛΗ IN LATER EPICUREAN AUTHORS
Voula Tsouna has recently argued that the testimony on ἐπιβολή in later Epicurean authors points to a different and, overall, less strictly empirical understanding of ἐπιβολή.Footnote 48 In what follows, I will examine this claim, beginning with the occurrence of the term in authors who write in Latin. First, the typical Latin translation of ἐπιβάλλω is inicio, and accordingly both Lucretius and Cicero typically use some form of this verb to translate ἐπιβολὴ τῆς διανοίας.Footnote 49 In On the Nature of Things the term appears three times. All of these occurrences are in Book 2 of the work, which deals with atomic theory, not in Book 4, which deals with perception, as one would perhaps expect. The first occurrence of the term is at line 740, where Lucretius discusses the idea that the mind of a blind person can think of bodies devoid of colour through a mental act: ‘If by chance you think that the mind is unable to become cognizant of such particles, you are wandering far astray’ (in quae corpora si nullus tibi forte uidetur | posse animi iniectus fieri, procul auius erras, Lucr. 2.739–40).Footnote 50 The second occurrence is at line 1047. The respective passage marks the beginning of a discussion on the innumerability of different worlds beyond our own, which Lucretius claims is to be grasped in a mental act (2.1044–7):
For, since the totality of space out beyond the ramparts of our world is infinite, my mind seeks the explanation of what exists in these boundless tracts which the intelligence is eager to probe and into which the mind can freely and spontaneously project itself in flight.
The third occurrence, finally, can be found at line 1080, if Lipsius's emendation of inice mentem for indice mente is correct. There Lucretius adduces an argument for the likelihood of an infinite number of worlds, namely that, since we can observe a principle of non-uniqueness in living creatures, we ought also to adopt the principle with regard to the number of worlds, with the following words: ‘To begin with, direct your attention to living creatures’ (in primis animalibus inice mentem, Lucr. 2.1080).
As Tsouna rightly observes, the passages employ the term with different semantic rigour. This is unsurprising, though, since we already saw that Epicurus himself also uses ἐπιβολή in different senses, and, as far as Epicurean vocabulary is concerned, Lucretius is not always a reliable source. To take a parallel case from Epicurean epistemology, Lucretius uses notitia and notities multiple times in On the Nature of Things,Footnote 51 but it is not clear that he is always rendering the same Greek technical term and so whether all instances of the term translate the Epicurean technical term πρόληψις.
With this caveat in mind we can examine the passages in more detail. The third passage quoted above makes clear that by inice mentem Lucretius here refers to any act of attention to something. By contrast, the projection of the mind that Lucretius mentions in the first passage seems to be used in the general sense of thought. After all, the passage states that a blind person can recognize an object with the help of the sense of touch. I take this to mean that it is possible for a blind person to think of a body, namely in so far as this thought is dependent on the sense perceptions that a blind person has (which will not include a sense of what colour the body is). Finally, the second passage discusses an application of the mind as a faculty of direct perception for what is not directly observable by the five senses: the mind projects itself into a realm it cannot directly experience, perhaps even with the help of inferences, given the nature of the object. Accordingly, there is no equivalent for such a usage of the term in Epicurus. In fact, such a usage seems a further development of the Epicurean position.
This last understanding is also found in Cicero's On the Nature of the Gods. Arguing against the conception of an interventionist Stoic god, the Epicurean spokesperson Velleius invokes, in remarkable similarity to Lucretius, an ἐπιβολή of space beyond our experience (Nat. D. 1.54):Footnote 52
cuius operam profecto non desideraretis, si inmensam et interminatam in omnis partis magnitudinem regionum uideretis, in quam se iniciens animus et intendens ita late longeque peregrinatur ut nullam tamen oram ultimi uideat in qua possi insistere.
[W]hose [that is, the Stoic god's] intervention (in the world) you assuredly would not require if you would but contemplate the measureless and boundless extent of space that stretches in every direction into which, when the mind projects and propels itself, it journeys onwards far and wide without ever sighting any margin or ultimate point where it can stop.
Given the similarity of the passages in Lucretius and Cicero, we have to take seriously a kind of non-empirical application of the mind, a direct perception of what is otherwise ἄδηλον. This is all the more the case when we look at the usages of ἐπιβολή in Philodemus, who uses the term several times in his extant writings, including in the passage in On Methods of Inference that was already quoted at the beginning of the paper and that may provide additional evidence for the criterial nature of ἐπιβολαί.Footnote 53 The relevant usages occur in On the Gods and in On Death.
In On the Gods 1, Philodemus first uses ἐπιβολή to refer to a general kind of thought. In the context of the discussion regarding the mental distress caused by certain thoughts about the gods, he writes (Phld. D 1, col. XIV.8–12; transl. mine):
καὶ μὴν ὅ γε τέλει[ο]ς ἄνθρωπος, ὅταν ἐπὶ τοὺς θεοὺς ἀνεπίβλητος ᾖ διειλημμένως, ἀδιαλήπτως ἐπι[βάλ]λει πολλάκι[ς]⋅ κἂν μηδ᾽ οὕτως, ἀλλὰ τήν [γ᾽ ἐκ] τῶν ἐπιβολῶν ἔχει ταραχὴν διαμέ[νου]σαν.
Even the adult human being, whenever he is inattentive to distinctly perceiving the gods, many times applies their mind to them in an indistinct way. And even if he does not do so, he is in a state of persisting mental distress stemming from his thoughts.
In On the Gοds 3, Philodemus uses ἐπιβολή to designate a general act of attention (Phld. D 3, col. II.23–7; transl. mine):
ἀξιωτέον δ᾽ ἀδιαλείπτως γε τοῦτο ποεεῖν, καὶ κατασκευαστέον τοῦτο, δι᾽ ὧν εἰώθαμεν, τῶ[ι] τὴν συνεχεστάτην ἐπιβολὴν ἐπὶ τὰ γεγονό[τ]α κ(αὶ) παρ[ό]ντα [κ(αὶ) μ]έλλοντα ἀγ[α]θά.
One must think it worthy to do this incessantly, and one must procure it. Through these things we are accustomed on the grounds of a continuous application (of the mind) on past, present and future goods.Footnote 54
However, in this passage the act of attention also extends into the future, and so cannot refer to a criterial use of the term. Overall, what is exactly meant by this passage is unclear, because the referent of ‘this’ cannot be reliably reconstructed. Yet even so the meaning of ἐπιβολή in this passage as well as in the previous passage can be said to mirror closely the first and second meanings of the term that I distinguished in the previous section.Footnote 55
At the end of On Death, by contrast, Philodemus writes (Phld. Mort. col. XXXIX.6–25 Henry; transl. Henry, modified):
ἀλλ᾽ ἐοίκασι διὰ τὸ φιλόζωον ἐκ τοῦ πεφρικέναι τὸν θάνατον, οὐ διὰ τὸ βιοῦν ἡδέως, καὶ τὰς ἐπιβολὰς τὰς ἐπ᾽ αὐτὸν ἐξωθεῖν, εἶθ᾽ ὅταν ἐναργὴς αὐτοῦ γένηται θεωρία, παράδοξος αὐτοῖς ὑποπίπτει, παρ᾽ ἣν αἰτίαν οὐδὲ διαθήκας ὑπομένοντες γράφεσθαι περικατάληπτοι γίνονται καὶ διξυμφορεῖν ἀναγκάζονται κατ[ὰ] Δημόκριτον. οἱ δὲ φρενήρεις, κἂν διά τινος αἰτίας ἀναγκαίας ἀνεννόητοι γένωνται τοῦ τάχ᾽ ἤδη συγκυρήσειν τὴν τοῦ β[ί]ου παραγαφήν, ὅταν ἐν ὄμματι γένηται, περιοδεύσαντες ἀρρήτως τοῖς ἀγνοοῦσιν ὀξύτα[τ]α καὶ τὸ πάντων ἀπολε[λ]αυκέναι καὶ τὸ τελέαν αὐτοὺς ἐπιλαμβάνειν ἀναισθ[η]σίαν, οὕτως ἀκαταπλήκτως ἐκπνέο[υσι]ν ὡς εἰ μηδὲ τὸν ἐλάχιστον χρόν[ο]ν ἐγλείπουσαν ἔχον τὴν ἐπιβολήν.
But because of an attachment to life that results from being frightened of death, not because they live pleasantly, they seem even to banish applications (of the mind) to it; then when observation of it becomes distinct, it comes to them as a paradoxical thing, for which reason, being unable to bear even to write a will, they are overtaken and surrounded, and are forced to bear a double burden of misfortune, as Democritus says. But persons of sound mind, even if as a result of some compelling cause they become unmindful of the fact that the finishing-line of life may immediately meet with them, (still) when it comes into view, they survey with a great speed that cannot be described to those unfamiliar with it both the fact that they have enjoyed everything and the fact that complete unconsciousness is taking hold of them, and expire as undauntedly as (they would) if their application (of the mind) had not been wanting even for the briefest period.
Here, ἐπιβολαί are again described as acts of focussing on something. In this case, this something is thinking of the agent's life in the face of death, which has the beneficial consequence of making the experience of dying easier for the agent with the ἐπιβολή. This usage is thus similar to the second sense of ἐπιβολή distinguished above. However, Tsouna contends that this passage also shows that ‘Philodemus advances the original and significant suggestion that … it can be a mental act of the greatest intensity and comprehensiveness …, by which the good Epicurean simultaneously summarizes and vindicates his life, and also affirms his complete acceptance of his own mortality.’Footnote 56 If this is correct, it further supports the tendency visible in Cicero and Lucretius, namely that ἐπιβολαί can now also be used to refer to mental acts of great magnitude that can encompass objects that cannot be perceived in a simple way, be it by a perception of the sense organs or by a simple perception of the mind.
However, we are now faced with a puzzle: if ἐπιβολαί, as criteria, are kinds of simple mental perceptions, for instance, of the gods, as I suggested, it is striking that such mental perceptions are not mentioned by the later Epicurean authors who added ἐπιβολαί to their list of criteria. By contrast, if our main textual evidence indicates that later Epicurean authors innovated with regard to ἐπιβολαί, it is strange how these ἐπιβολαί can be criterial, that is, plausibly said to guarantee reliably the truth of the impressions they produce if they extend to objects that generally are grasped by inferences, not by direct sense or by mental perception. This would all be far away from Epicurean sensualist epistemology. Therefore, the following middle path seems the most plausible: while later Epicureans made certain kinds of ἐπιβολαί criterial, namely those that refer to mental perceptions, they also at the same time expanded the meaning of the term ἐπιβολή to include a special kind of mental act. Such a reading would allow later Epicureans to expand the usage of the term to include a looser meaning of ἐπιβολή in line with the generally expanded usage of the term during the Hellenistic period,Footnote 57 while at the same time making clear that the most sensible way to understand ἐπιβολή as a criterion is to make it a kind of mental perception.
