Alexander of Aphrodisias’ Criticism of the Stoic Theory of Perception: typos and typōsis

2.1 Stoic Debates on phantasia

Alexander does not name his opponents, but we can safely identify them as the Stoics.^[17] Some of the arguments echo the debates within the Stoic school, viz. Chrysippus’ polemic against taking impression literally (SE M VII 229, 373 = part of SVF II 56), and so commentators take Alexander as basically reciting Chrysippus’ arguments.^[18] Below, I show that despite similarities Alexander’s argument differs from Chrysippus’, and results in rejecting the Stoic account in favour of Alexander’s version of the Aristotelian view. Before analysing the argument, it is worth summarizing the Stoic views that are attacked.

According to Zeno, phantasia is typōsis in the soul (SE M VII 236 = SVF I 58; DL VII 45 = SVF II 53; DL VII 50 = LS 39A3; Cic. Luc. 77 = LS 40D3–4) in the literal sense of impressing physically, just like a signet ring impresses its shape into a piece of wax.^[19] Presumably, the same idea is expressed by Cleanthes in claiming that phantasia is impression involving depth and protrusion, kata eisokhēn te kai exochēn (SE M VII 228, 372–373, VIII 400; PH II 70 = SVF I 484). Alexander too takes these terms as the basic meaning of impression (De an. 72.5–13).^[20]

This literalist theory is rejected by Chrysippus (SE M VII 229, 373 = part of SVF II 56) on at least two grounds. (1) If the hēgemonikon had phantasiai of two objects with contradictory attributes at the same time, the same body (the hēgemonikon ^[21]) would have two contradictory attributes simultaneously (two different shapes, as the literal account of typos requires), which is impossible (SE M VII 229). Further, (2) there could be but one impression at a time (SE M VII 373; cf. DL VII 50 = LS 39A3). For the literal impression of one shape would obscure the literal impression of another, if they are impressed in the very same bodily part. But since impressions are taken to be into one body, the hēgemonikon, this consequence indeed follows (Argument from Obscuring of Affections). Moreover, as a corollary, accumulation of phantasiai would be impossible on Cleanthes’s theory. And since memory, according to the Stoics, presupposes many similar phantasiai (SE M VII 373; cf. Aëtius IV 11, 2 = LS 39A2), it would be impossible too. Thus, instead of the literal account, Chrysippus proposes an alternative definition according to which phantasia is alteration (heteroiōsis: SE M VII 230–231, 372 = part of SVF II 56; SE M VII 376; alloiōsis: DL VII 50 = LS 39A3; SE M VII 400) of the pneuma constituting the hēgemonikon. This is not a literal impressing, nevertheless it must be a physical affection,^[22] for there is no room within Stoicism for non-physical change. Thus, Chrysippus’ alteration is intended to be such as to allow for (1) simultaneous alterations by contradictory attributes and (2) consecutive alterations by multiple attributes so that the alterations are retained.

Notice that both of Chrysippus’ arguments presuppose that there are not several physical parts of the hēgemonikon into which the (simultaneous) impressions of different or even contradictory qualities and shapes could be distributed to avoid the absurd consequences. That is, the Stoic theory apparently presupposes the Indivisibility of the Central Sense-Organ: impressions modify the central organ of perception as a whole rather than parts of it.^[23]

This is remarkable, as Alexander seriously considers in his investigation of simultaneous perception a problem analogous to (1) Chrysippus’ first argument: the Problem of Opposites (In sens. 143.9–26; De an. 61.20–30; Quaest. III 9, 95.20–28).^[24] Alexander’s solution is indeed partly the rejection of the Indivisibility of the Central Sense-Organ, as he avoids the physical impossibility by arguing that the opposite perceptual changes from opposite perceptible objects should affect different parts of the central organ (In sens. 168.2–5; De an. 64.4–65.1; Quaest. III 9, 97.22–98.15). Moreover, in course of his discussion of simultaneous perception, Alexander himself poses the same problem for the Stoic account (In sens. 167.4–9; cf. Mantissa 4, 118.6–9). Accordingly, the hēgemonikon could not be in opposite states at the same time, only successively, so the Stoics cannot explain the possibility of simultaneous perception.^[25]

Thus, it seems that despite his objection to the literal account of impressing, Chrysippus’ own solution is liable to the analogous Problem of Opposites (at least according to Alexander). The problem for Chrysippus follows from two premises: (i) the Indivisibility of the Central Sense-Organ; and that (ii) the conception of alteration (the kind of modification Chrysippus proposes) does not allow the same thing to be modified in different ways simultaneously. Of these, Chrysippus clearly adopts (i). Perhaps his reason is to ensure the unity and simplicity of the soul and its ruling part.^[26] Nevertheless, he wants to deny (ii), and allow that several of his alterations (even contradictory ones) may coexist in one and the same subject. Whether or not he succeeds does not concern us here.^[27] Alexander probably believed that the Problem of Opposites is applicable to Chrysippus’ doctrine, because the alterations are nevertheless physical changes.^[28]

2.2 Alexander’s Argument (A1)

Turning to Alexander’s argument at De anima 68.10–21, let us start with (A1) against identifying the phantasia with the impression. Alexander derives two unacceptable consequences: (a) we would be in a state of phantasia without being active, simply by having the impression; (b) moreover, we would be in as many states of phantasia – with various content – as many impressions we have. Let us see the two consequences in turn.

First, (a) is prima facie question begging, as it apparently supposes Alexander’s own view that phantasia should be an activity of ours, different from perception. But, let us see if a better argument can be reconstructed. The consequence will follow if having an impression φ is sufficient for being in phantasia-state φ. Alexander does not specify what having an impression amounts to, but we can extract the sense from his initial account presented immediately before the argument (De an. 68.5–7, cited in Section 2). He claims that the impressions (or residues) are seated in the primary sense-organ, i.e. in the heart, as remnants of the perceptual motions that created them (cf. De an. 97.11–14). This suggests that the residues remain in their place in the heart, without the possibility of moving elsewhere. So we might say: for s to have an impression φ is for impression φ to be present in the central organ of s. So, replacing ‘having’ with ‘being present’ in our initial formula we get: if an impression φ is present in the central organ of s, s is in phantasia-state φ (Sufficiency of Impression’s Presence).^[29] Thus we can reduce the vague ‘having’ of an impression to the quite straightforward ‘presence’ in a local sense.

Now, it seems that the Stoics accepted that impressions are present in the central organ. For they believed that impressions are in the soul, or in the hēgemonikon, or more properly impressions (i.e., phantasiai) are the hēgemonikon pōs echon, the ruling faculty in a certain state, which indeed applies to every mental state.^[30] Now, since the hēgemonikon is the subject of the occurrences of phantasiai, phantasiai cannot be seated but at the very same place as the hēgemonikon. Since the hēgemonikon is the pneuma in the heart, phantasia-impressions are also in the heart. In this theory it makes no sense even to say that phantasia is elsewhere (either on the literal interpretation or Chrysippus’ alteration). Again, if one identifies phantasia with impression (as the Stoics), then the presence of the impression will constitute the occurrence of phantasia with a particular content. Further explanation how a phantasia may occur is not needed. So, the Sufficiency of Impression’s Presence is also accepted by the Stoics.

Alexander’s problem with the Sufficiency of Impression’s Presence is that it leaves the subject without an activity concerning the impression, it requires only the presence of a physical item.^[31] That is, the Stoic account implies that for a psychological state (phantasia) to occur it is sufficient that a bodily item is located in a certain area in the body of the living being. For Alexander this does not constitute an explanation of the psychic phenomenon.

The other consequence (b) (we are in as many phantasia-states as many impressions we preserve) requires a further premise. This is because a preserved impression does not necessarily mean an impression that we have, viz. that is present in our central organ. We may preserve impressions somewhere else – e.g., in another organ, or in the vascular system as we shall see for Aristotle on dream – or being preserved in the central organ may constitute less than being present in it (e.g., it may be present only potentially, to use Aristotelian terminology). To rule out such possibilities, it must be supposed that every impression preserved by s is always present in the central-organ of s (Constant Presence of Impressions).

As it is clear from the above description of the Stoic view, the Stoics adopted the Constant Presence of Impressions. For impressions may only be located in the hēgemonikon, so if an impression is preserved, it is in the hēgemonikon. Again, it is plausible to understand the Stoic view so as the impression is present in actuality (and not on a lower level like potentiality), since arguably phantasia (thus the impression) in itself involves awareness.^[32] It is clear that this argument of Alexander’s is not the same as that of Chrysippus’ argument (1) in Section 2.1, against the literal interpretation of impressing, as it was identified as analogous to Alexander’s Problem of Opposites concerning simultaneous perception.

Thus, Alexander’s argument works against those who accept both the Sufficiency of Impression’s Presence and the Constant Presence of Impressions, as the two premises together entail the unacceptable consequences. Alexander (plausibly) takes the Stoics, including Chrysippus, to accept both premises,^[33] and continues with the assumption that the Sufficiency of Impression’s Presence should be dropped and the Constant Presence of Impressions may be accepted. Indeed, as noted, Alexander has reasons to accept the Constant Presence of Impressions (cf. De an. 68.4–9, 97.11–14).^[34] Before we move on to Alexander’s considerations following the denial of the Sufficiency of Impression’s Presence, it is instructive to see what it would look like to drop the Constant Presence of Impressions, so let us see Aristotle’s account of dreaming.

First, Aristotle apparently denies the Constant Presence of Impressions, as his phantasmata (the items analogous to impressions) are not always in the heart or primary sense-organ (where they can appear), but they can be in potentiality somewhere in the vascular system or in the peripheral sense-organs (cf. Insomn. 3.461b11–21),^[35] and they are taken (down) into the heart by the movement of the blood in sleep (Insomn. 3.460b32–461a8).^[36] Aristotle also denies the Sufficiency of Impression’s Presence. Having arrived into the primary sense-organ, phantasmata do not automatically appear, but further physiological conditions are necessary to be met (ibid.): (A) absence of larger movements, (B) absence of disturbance.^[37] That is, the presence of phantasmata is not a sufficient condition for appearing (for the dream-phantasia). Nonetheless, as Aristotle does not mention other factors, the physiological conditions taken together seem to constitute a sufficient condition. Hence, no further condition must be met for phantasmata to appear, in particular, no need for a specific activity of phantasia.^[38] As we can see, Alexander requires precisely this: an activity of phantasia in the explanation why an impression appears in a mental state involving phantasia. In this regard, Alexander’s explanation seems to be more psychological in nature than Aristotle’s physiological account of dream appearance.

So far we have seen that Alexander’s argument against the Stoic account of phantasia as impression differs from Chrysippus’ polemic against Cleanthes’ literal account. Indeed, the latter is analogous to Alexander’s Problem of Opposites, presented in the context of simultaneous perception, which Alexander also takes to apply to any Stoic view. Again, the analysis of Alexander’s argument shows that it aims at motivating to drop the Sufficiency of Impression’s Presence while keeping the Constant Presence of Impressions; so it is not only against any Stoic account of impression, but implicitly at odds with Aristotle’s account of dream appearance.

2.3 Alexander’s Argument (A2)

Having denied the Sufficiency of Impression’s Presence, Alexander goes on to see (in A2 of De an. 68.10–21) what other factors (activities of the soul) the Stoics could add as conditions for phantasia-states to occur. He considers two candidates for the phantasia-activity – (i) the ongoing impressing, (ii) the completed impressing – and accepts neither. Let us see the two candidates in turn, and then what Alexander proposes instead.

If the activity is (i) ongoing impressing, the generation or creation of an impression, it will be identical with perception. For, according to Alexander, the impression is the residue that comes about as an effect of perception; i.e. the process in which the residue comes to be is perception itself.^[39] Actually, this is not far from the Stoic theory, according to which perception (aisthēsis) is an experience by means of a phantasia;^[40] even though they did not restrict phantasia to the perceptual case.^[41] Alexander cannot accept this, since he has already distinguished phantasia from perception (De an. 66.24–67.9), and phantasia for him is not a process or activity that creates residues,^[42] rather, one that uses them. Moreover, he wants to explain a wide range of mental phenomena by phantasia, which could not be done if phantasia were identical to perception, for perception is restricted to cases when its object is present.

Alternatively, if the activity was (ii) a completed activity (indicated by perfect tense: gegonuian), it would define memory. Again, memory is only one phenomenon that phantasia is to explain, and the remainder cannot be explained by memory, as it is restricted to the past, with experiences that have been perceived. Yet, even though we possess but some notes from Alexander’s account of memory (for references, see Section 3.1), from those it is clear that a completed residue (or impression) is insufficient for memory. It is also required that the residue is an image (eikōn) of the perception of the past event. The present remark (De an. 68.20–21), however, seems to pick out the Stoic conception of memory, according to which it is the storing of phantasiai (SE VII 373 = SVF I 64; II 56).^[43] The completed impressions constitute a set of impressions that remain still and supposedly available to the agent. So, if the remark is taken as specifically against the Stoic account, it suffices to be said that they themselves gave a wider role to phantasia than to memory, and so a definition of phantasia that picks out memory is inadequate.

Alexander concludes from the argument that phantasia must be a distinct activity; not (i) the creation of an impression (= perception), nor (ii) the completed impressing (= memory), yet necessarily related to the impression. He does not specify the relationship and the activity further, only implies its analogy to perception: the object of phantasia is a sort of perceptible (tina/hōsper aisthēta, cf. De an. 69.1, 10). It is not my aim here to analyse the activity of phantasia as understood by Alexander;^[44] instead, let us see how Alexander proceeds from his polemic against the Stoic account, to better assess its import.

2.4 Alexander’s Argument in Context

Alexander supposes the existence of an activity by invoking Aristotle’s tripartite scheme of power/activity/object (De an. 68.21–30) which he uses as a framework for his psychological investigation (cf. De an. 32.23–33.9, 40.15–19).^[45] But once he has applied the scheme for phantasia, he needs to identify the object postulated for phantasia. He accomplishes this by saying it is an internal perceptible object (De an. 68.31–69.2). Alexander takes the object to be internal, as phantasia is supposed to occur when the corresponding perceptible object is not present, so that perception properly speaking is impossible. Since there must be an object to cause the state, the object has to be internal, present within the central organ. Thus, Alexander posits phantasta (objects of phantasia) to solve the problem of presence in absence or representation of absent objects.^[46] Once the object of phantasia is identified and distinguished from the object of perception, it follows that the power of phantasia also differs from the power of perception, and so constitutes a distinct power of the soul. This move is noteworthy, as for Aristotle the relationship between phantasia and perception, and the status of phantasia is not that clearly specified.^[47] Alexander concludes his argument at De an. 70.3–5 by opposing the Stoic view (τὸ λέγειν τύπωσιν ἐν ἡγεμονικῷ) that it fails to acknowledge the proper identity of phantasia as activity, for it would put phantasia in the residue (ἐν τῷ ἐγκαταλείμματι) instead.^[48]

Thus, it seems that Alexander first shows that (A1) there has to be an activity of phantasia related to an impression (A2) distinct from the generation of impression (perception) and the retaining of the impression to remember past events or perceptions. This he achieves through a quick polemic against a generic Stoic view, picking out only the essence of the theory; and so this passage (De an. 68.10–21) cannot be used as an independent source for Stoic theory (although part of it is printed as SVF II 59). The phantasia activity is, then, called for in cases when the external object about which the mental state has content is not present. In these cases, there must be an internal object (residue). Then, the power of phantasia is identified as the power of making such mental states as activities possible, so a power distinct from perception.

3.1 Occurrences of the ‘typos’ Terminology

This point is further justified by the fact that the terms of ‘impression’ rarely occur in Alexander outside the context of the arguments against Stoicism. Indeed, ‘typōsis’ never occurs in other contexts. ‘Typos’ is used elsewhere in its ordinary senses as ‘mould’ (e.g., In An. Pr. 6.16–18; In Metaph. 57.6^[53]), and mostly as ‘telling something in outline’ (e.g., Mantissa 25, 186.11; De an. 60.3; In Metaph. 463.17; 464.1; 579.25, or several times in In Top.). In three passages, however, Alexander apparently replaces Aristotle’s term ‘phantasma’ by ‘typos’, and uses the typos terminology in his own voice. These are discussed in the following paragraphs.

The first occurrence, at De an. 83.4, comes approximately 10 pages after Alexander’s caution about the metaphorical meaning of the term, which could explain its use in itself, but more can be said. The context here is concept formation, which starts with perception, goes through memory (involving phantasia) and experience.^[54] Alexander claims that in each case of perception an impression comes to be (τυπούμενος) which is preserved in memory (De an. 83.2–10).^[55] Alexander puts forward the same account of perception – as generation of impression – earlier in the treatise, and also elsewhere. (1) As we have seen in Section 2.3, in his polemic against the Stoic view he says that taking phantasia as the generation of impressions would actually define perception (De an. 68.16–20). Again, (2) in discussing phantasia, Alexander identified perception in activity as “possessing in itself this impression that [came to be] from perceptible objects that are external.” (De an. 69.4–5)^[56] Here, perception is contrasted with phantasia insofar as the external object is present in perception, but absent in phantasia, which relies on internal objects that remain as residues (enkataleimma) of perception (69.2–4). The passage occurs in the context of Alexander’s argument for showing that phantasia always has its origin in perceptions and hence can be called ‘perception in activity’ (68.31–70.5). Thus, he aims at keeping continuity between residues and perception through the impressions that are possessed in perception and kept in phantasia as residues. By identifying ‘perception in activity’ as ‘possession of an impression’, it is applicable to phantasia and perception alike; whereas ‘generation of impression’ would only be applicable to perception and not to phantasia (cf. 68.16–20). Finally, (3) in Quaestiones III 7 – his commentary^[57] on Aristotle DA III 2.425b12–426a2 on self-awareness of perception – Alexander, in appealing to Aristotelian physics according to which the activity of an agent and that of the corresponding patient is one and is present in the patient, writes that “the being of perception in actuality consists in possessing the form of the thing perceived without its matter”^[58] (Quaest. III 7, 92.34–35; cf. De an. 83.13–23). Since the perceptible form is received in perception from the object through the object acting upon the perceiver and so assimilating the perceiver to itself (in the relevant way),^[59] the object’s acting upon the perceiver can be identified as the object producing an impression in the perceiver. Thus, impression is related to one aspect of perception: passive receptivity. Again, as the object assimilates the perceiver to itself so that the perceiver receives its form, the object produces an impression in the perceiver about itself and its form. The content of the impression is identical to the perceptible form received. So, since perception can be identified as the possession as well as the reception of form, it can also be described as the possession just as the generation of impression. Thus, referring to the generation of impression (τυπούμενος) in perception seems to be related to (a) the passive receptivity of perception, and (b) the continuity between perception and phantasia which is sustained by the remaining of the affection as a residue of perception. However, these aspects are better characterized by other terms: (a) receptivity as ‘assimilation’ or ‘reception of form’; and (b) remaining as ‘residue’. So, after all, even though Alexander uses the ‘typos’ terminology at De an. 83.4, on the one hand its import is very thin, and indeed better expressed by Alexander’s preferred alternatives, and on the other hand the passage occurs 10 pages after the explication that ‘typos’ is to be used metaphorically.

The second problematic occurrence of ‘typos’, at In Metaph. 4.12 Golitsis (= 3.17 Hayduck),^[60] is concerned with memory, occurring in the context of distinguishing different kinds of intelligence (In Metaph. 3.22–4.28 G = 2.22–4.11 H). The last of the senses identified is “the natural versatility in regard to the performance of actions that is found in animals capable of remembering” (In Metaph. 4.9–10 G = 3.13–15 H, translation by Dooley). This calls for commenting on memory, so Alexander cites Aristotle’s definition: “memory is having a phantasma which is like an image of that about which the phantasia is” (In Metaph. 4.11 G = 3.15–16 H).^[61] In Alexander’s explanation “the impression according to the phantasia is not sufficient for memory, but the activity concerning the impression must also be concerned as with an image,^[62] that is, it must be as from something else that has happened” (In Metaph. 4.11–13 G = 3.16–18 H).^[63] What is relevant from this now is that Alexander uses ‘impression’ (typos) instead of ‘phantasma’.^[64] However, this should not be taken to imply that he adopted a ‘typos’ terminology in favour of the term ‘enkataleimma’. Since Aristotle himself applies the term ‘impression’ in explaining memory (cited in Section 2) perhaps in the context of a commentary on Aristotle’s account of memory it is appropriate to apply the same terms that one finds in Aristotle. Replacing ‘phantasma’ with ‘typos’, then, need not imply that ‘typos’ is the most appropriate term to use in this context, only that it is more appropriate than ‘phantasma’ due to the fact that Aristotle used it too, and presumably because ‘phantasma’ acquired a deflationary meaning (related to error) in Hellenistic philosophy. Alexander indeed avoids using the term ‘phantasma’ in general, or replaces it with other terms. He only uses the term in citing Aristotle and reflecting on his usage; or in Hellenistic senses – meaning a figment of the mind,^[65] or in the broad sense of appearance^[66] – in arguing against the Stoics. Again, ‘phantasma’ is replaced with different terms: (1) ‘phantaston’, the object of phantasia;^[67] (2) ‘enkataleimma’ (residue): at In Metaph. 433.4–5 phantasmata are said to have some existence as enkataleimmata;^[68] (3) sometimes with ‘phantasia’; (4) ‘typos’, at In Metaph. 4.11 G (= 3.17 H), as we have just seen.

In the third problematic occurrence of ‘typos’, at In Metaph. 312.3, Alexander discusses that not all perception is true, and in course of this he distinguishes perception and phantasia (In Metaph. 311.24–312.11). The differentiation starts with a recapitulation of the account of these powers:

phantasia is a motion of actual perception; this motion is the result of perceptible objects when impressions come (into being) inside, and it happens to take place in different ways at different times, as he has shown in On the Soul and On Memory and Sleep.^[69] (In Metaph. 312.2–5)

Here again, ‘impression’ is used for the effect of the activity of perception that comes about inside, which later can be used in different ways in different mental states. This effect is the residue of De anima, so why is it called ‘impression’ here? Since this passage is not connected to memory or to Aristotle’s text, the previous explanation is not applicable here. But, in the context of truth and falsity in perception and in phantasia Alexander only wants to make a quick distinction between phantasia and perception, and perhaps this is appropriate without reference to residues (enkataleimmata). Moreover, he does refer to Aristotle’s works (especially On Memory) in which the term ‘typos’ appears in relation to phantasia, which explains Alexander’s use.

There is one particular compound with the term ‘typos’ that Alexander applies in his account at De an. 70.13 (occurring once in the whole Greek corpus):^[70] prosanatypoun, ‘impressing further’. The fact that the term is compounded from typoun renders it as not a simple application of the term ‘impressing’ (typoun). For this reason, I only mention that it is apparently used for a mechanism of phantasia to complete residues that are incompletely preserved to get an appropriate residue for phantasia to represent its content. This fits nicely with Alexander’s account that the original generation of residues in perception can be called metaphorically as ‘impression’.^[71]

Thus, Alexander, besides showing the inadequacy of the Stoic theory of phantasia appealing to impression insofar as they miss to posit a specific phantasia activity, replaces the terminology of ‘impression’ for ‘residue’, and uses ‘impression’ only metaphorically. Presumably he keeps the metaphor because Aristotle appealed to it too, but what remains from it is quite thin, amounting not much more than to being a physical change with an obvious cause.