by A. A. Long
In some other cases, however, Theophrastus’ testimony, or rather the lack thereof, is baffling. We have already noted that Theophrastus shares Aristotle’s strategy of sticking to the second (“false”) part of Parmenides’ poem and omitting all mention of Parmenides’ remarks on thinking and cognition in the first (“true”) one. His procedure in dealing with Democritus is also strange, for the only sentence devoted to Democritus’ explanation of thought, difficult though it is, shows that Theophrastus did not intend to give a functional account of what thinking is, as he probably could (and, if so, should) have done: “On the topic of thinking, he said no more than that it comes about when soul is balanced after movement;28 but if someone gets over-heated or too cold, he says it changes” (58). Even more puzzling is his attitude to Anaxagoras. Anaxagoras, if anybody, is the philosopher who postulates the purity of the intellect (nous), and Theophrastus must have known about Anaxagoras’ view that “from the weakness of our senses we cannot judge the truth” (DK 59 B21a).
Thus, for all its scruples and precision, Theophrastus’ treatise does not give the impression of having dealt adequately with the difference between the senses and thought. One could argue that, since he was writing a work On the senses, the distinction between the senses and thought was somewhat incidental to his purpose. Still, given that he is looking for evidence concerning this distinction in early Greek thinkers, the picture that emerges looks strangely distorted. Is this only due to Theophrastus’ shortcomings? Might it not also be the case that, although the distinction was vital to them, they did not indeed draw a clear line between the two – clear, that is, according to Peripatetic criteria, let alone according to our own?
At this point it seems appropriate to refer to what is known as “the developmentalist view” about cognitive theories and cognitive terminology in early Greek philosophy. There are, broadly speaking, two main components to this view:
(a) Knowledge, in Homer, is on the whole “perceptual,” and ultimately intuitive.
(b) In spite of the growing importance of nous as a means of access to “truth,” or of going beyond the appearances, the views of early Greek philosophers about thinking (and knowledge) remained heavily indebted to, and so to speak, under the spell of the Homeric model of intuitive knowledge.
Although, or rather because, this view does not claim that knowledge is equivalent to perceiving but only that it is ultimately to be construed on the model of perceiving, it can be seen as the modern equivalent to the old Peripatetic claim about identity between perceiving and thinking in earlier philosophers. Is there more to it than to its ancient counterpart?
The developmentalist view has recently been submitted to careful criticism by J. Lesher.29 According to Lesher, not only did early Greek philosophers not identify perceiving and thinking (the Aristotelian thesis), but they also did not even conceive of thinking on the model of perceiving (the developmentalist view). Rather, thinking was thought to be fundamentally reflective, a property not shared by sense percepion.
The best evidence for this latter view is provided by Parmenides B8, where the process of “thinking what is” amounts to a series of inferential steps that Lesher has pointedly compared to Penelope’s recognition of Odysseus in Homer (see p. 239 in this volume). Identifying what is Odysseus, and recognizing him for who he is, are not questions of perceiving or quasi-perceiving, but of carefully testing signs and following the course of an argument.
Other texts quoted by Lesher (such as Heraclitus B93 and B101) are more difficult to deal with, but support for a nonintuitive conception of knowledge and thinking can probably be drawn, fairly generally, from the cosmic or universal function that intellectual entities play in early Greek though. Empedocles’ “holy mind,” which extends through the universe (DK 31 B134.4), Xenophanes’, Anaxagoras’, and Diogenes’ “intellect,” as well as Heraclitus’ “reason” (logos), are more easily construed as deliberating, organizing, or structuring powers, than as intuitive capacities. But caution is also in order. One should be wary not to make a mistake symmetrical to Aristotle’s, and to resist the temptation to generalize from a relatively small body of evidence. Even the most suggestive testimonies in favour of the reflective, or, as one could call it, dianoetic conception of thinking, remain for the most part implicit. Drawing conclusions about what an author’s views on thinking were from an actual bit of thinking (such as the argument of B8 in Parmenides’ case) or from the role explicitly ascribed to it (as in the case of Anaxagoras’ “intellect” in B12) is quite different from interpreting explicit statements about what thinking is. Moreover, there are reasons to doubt whether the activity of thinking was of any concern in the first place: for instance, it is significant that when Empedocles says that thinking is blood, he identifies it with its location,30 as if what thinking consists in was taken for granted. Thus it could be the case that seemingly good candidates for a “dianoetic” conception of thinking processes coexist with or rather turn out to fit the “intuitive” or “noetic” mould. After all, it is not before Plato that the difference between dianoia and nous was articulated.
The specific question about how early Greek philosophers conceived of the relationship between sensation and thought, raises the same kind of difficulty as the one concerning the nature of thought. Again, the explicit evidence is scarce. That at least one of them must have explored this relationship is certain, for Plato refers to such theories in the Phaedo as typical of their interest:
Is it blood that we think with, or air or fire? Or is thought due to something else, namely the brain’s providing our senses of hearing, sight, and smell, which gives rise to memory and opinion, and ultimately, when memory and opinion have acquired stability, to knowledge? (96a-b)
Curiously enough, however, our main direct evidence on this topic is negative, as it comes from Parmenides and Heraclitus.31 Which is not to say that it is not interesting; on the contrary, these testimonies give grounds for thinking that even antiempirically minded thinkers could “save the senses” in a way that makes them much more important than one might have thought.
Take Parmenides B7.3–6 first:
Nor let custom born of much experience force you to ply along this road
an aimless eye and echoing ear
and tongue, but judge by discourse a much-contested testing
spoken by me.32
Despite apparences, I think it is a mistake to say (as is often the case) that Parmenides rejected the senses. What is true is that the senses cannot contribute to knowledge of truth. But what Parmenides’ goddess promises is to teach mortal opinions as well as knowledge of the truth (B1, B10). Now certainly this implies exercising sense perception and exercising it in a correct way. It should be stressed that B7 does speak about sense perception.33 Although the two terms akoê and glossa imply understanding and speech, not sensation, the linkage of akoê with omma must refer to sight and hearing. Now, what should we do with the epithets askopon and êchêessan? A majority of interpreters assume that their function is definitional. According to this view, eyes and ears are by nature “aimless” and “hollow” (literally “echoing”). But something is to be said in favour of a more restrictive construal. Parmenides does not here simply reject the use of the senses, but does so only in as much as they are “aimless” and “hollow,” that is in as much as they contribute to the deeply entrenched habit linked with experiential knowledge (ethos … polypeiron).34
This being said, we can be certain that Parmenides did not explain what the positive, “targeted,” use of the eye might be (how to look properly for instance at the moon’s wanderings), or what the “full” use of the ear is like (how to listen rationally to human discourse). In this respect, he is rather close to Heraclitus B107 (“Evil witnesses are eyes and ears for men, if they have souls that are barbaric”35) or B55 (“all that of which vision and hearing are learning, this is what I prefer”36). The implication of both fragments is that, under certain conditions (of wisdom or insight), the senses
might well be “good witnesses.” Empedocles thought this too, for he urged his disciple Pausanias to exercise sense perception in a full-blown way – the only way in which the senses could transcend their fragmentariness and help to achieve the synthetic grasp that he made the distinctive mark of thinking:
But come, observe with every power in what way each thing is clear, without holding any seeing as more reliable compared with hearing, nor echoing ear above piercings of the tongue; and do not keep back trust at all from the other parts of the body by which there is a channel for understanding, but understand each thing in the way it is clear. (DK 31 B3)
3. THE PHYSIOLOGY OF SENSATION AND THOUGHT
In rough contrast with the epistemological questions we have touched upon, we are fairly well informed, thanks mainly to Theophrastus’ treatise On the senses, about how sensation and thought function physiologically. There is a tendancy to oppose this purely physiological interest to a nobler, more philosophical one, which would presumably bear on those very epistemological questions that are so elusive in the extant evidence. This imbalance in our sources between epistemological and physiological considerations may in part be due to the hazards of transmission, but I am inclined to think that there is something authentic about it, provided that, following Plato’s and Aristotle’s use of the word physiologoi, we redefine what physiology means when applied to the early Greek philosophers.
On the basis of Theophrastus’ detailed presentation, one can see that beginning at least with Empedocles, doctrines about sense perception tend to fight on common grounds. For all their differences, they operate with a relatively closed set of data, beliefs, and questions. This is especially clear in the case of vision, which, as is only to be expected, attracts much of the attention: as far as cognition is concerned, it is the most important of all the senses (together with hearing), and the eye is aesthetically as well as emotionally one of the most valuable parts of the human body. Almost every theory has something to say about the function of the watery substance on the surface of the eye (Theophrastus, Sens. 7, 26, 50) or about the image of the object that is reflected in the pupil (Theophrastus, Sens. 36, 40, 50). There is a typical and remarkable pattern in the overall presentation of the theory. In Theophrastus’ reports about Empedocles, Anaxagoras, and Diogenes, the explanation of how the different senses work is followed by a section devoted to differences in acuity, both within a given species, namely human beings, and between human beings and other animals (8, 11, 29, 40, 50, 56). Why certain individuals, or certain animal species, see better at night than during the day is also part of the menu (8, 27, 42), as well as the topic of the relationship between perception on the one hand, and pleasure and pain on the other hand.37
In spite of deep disagreement in the explanations themselves, the types of explanations also reveal a set of relatively homogeneous preoccupations.
Sensation itself is never a problem. It is rather, something like a given capacity, whether it is attributed to the elementary principles (as in Empedocles and Diogenes) or to a specific organ (as in Democritus). What needs to be explained in the first place, is the way in which the object of perception meets the perceiving organ. Hence a double emphasis on what can be called “topology”: early Greek doctrines about the senses are largely stories about travelling, going through, and reaching.
The object does not itself penetrate the organs but reaches them by delegation only. Accordingly, the classical scheme is that of Empedocles’ “emanations,” which are perhaps already foreshadowed in Parmenides.38 It is significant that Democritus’ images, usually called eidôla, could also be referred to as emanations (see especially 50, 51). One particularity of Democritus’ theory, on which Theophrastus insists at length (50–53), is that those images do not themselves reach the eye. What gets into the eyes are “imprints” (typoi) that the images coming from the object, as well as our own emanations, have impressed on the intermediary air (51). The rationale for adopting such an intricate scheme must have been that it facilitated explanation of perceptual deformations, as well, perhaps, as the perception of distances. According to Aristotle’s famous testimony about Democritus’ theory of vision, if the sky was void of air, we would see an ant on the celestial vault (De an. II.7 419a15–17).39 As far as transportation is concerned, it is more difficult to see what Anaxagoras’ and Diogenes’ views were. But Anaxagoras’ point in adopting the common view according to which the image of the object is reflected on the pupil (27, cf. 36) may have been a particular instance of the principle that “what appears is vision of the invisible” (DK 59 B21a). In this case, some kind of transportation must have taken place, since the image in the eye was there. And when Diogenes claims, strangely enough, that the image on the eye must “mingle” with internal air in order for perception to occur (40), he implies that the image itself must have reached the eye.
The counterpart of this interest in emanations is the attention paid to “passages” (called poroi by Empedocles). There are many of these. In the first place, there are the passages constitutive of the sense organs – ears and nostrils are the most obvious instances. But how is the eye penetrated? Empedocles describes how “passages” of fire and earth alternate at the surface of the eye, so that it can receive what is shining and what is dark (Theophrastus, Sens. 7). Democritus invokes “suppleness” and “vacuity” to explain how the “image” penetrates the eye (50, 54), Alcmaeon (perhaps) and Clidemus (certainly), speak of its “diaphanous” nature (26, 38). Beyond the eye, the way must be clear, the channel pierced in a straight line, free of greasy matter or blood (Democritus, 50, cf. 55/56; Diogenes, 40). If the tongue, in Diogenes, is the organ most sensitive to taste and pleasure (the same word in Greek: hêdonê), this is because it constitutes the point where the vessels coming from the whole body concentrate (43). On the other hand, if fish as well as young children are stupid, this is due to air being unable to disseminate, in the case of fish, because their flesh is too compact, and in the case of children, because there is still too much of the original humidity blocking the channels (44, 45). Passages can be minute, even invisible. Empedocles held that we respire through the skin (DK 31 B100) and Democritus admitted that sounds penetrate through the whole body, not through the ears only (55).
The key function of passages in early Greek theories of perception perhaps explains the paradoxical status of touch. Aristotle remarks in the De sensu that early Greek thinkers, prominently represented by Democritus, had promoted touch to the principle of explanation of the other senses (442a29). Theophrastus agrees in Democritus’ case (De sensibus 55), and says about Empedocles that adaptation to the passages is a kind of touch (15, cf.7). No doubt this analysis in part reflects the Peripatetic doctrine that all sensations, including touch, operate through a medium.40 On the other hand, touch is strikingly neglected in early Greek theories. Anaxagoras is the exception. Theophrastus thinks it worthwhile to report his opinion, because it played a role in establishing, against most other thinkers, the principle that sensation occurs though opposites (28, cf. 2),41 but he insists that others have almost nothing to say about touch. This silence is extremely revealing. If touch does not as a rule require independent consideration, that is because it does not imply any kind of travelling. In this sense, Aristotle’s remark is justified; touch, potentially at least, is an explanans rather than an explanandum.
No wonder, then, if interest in the specific senses decreased proportionately to their proximity to touch. Taste requires attention only if distance is reintroduced by the admission of a central organ, and hence of an internal distribution, as in Alcmaeon (25) and Diogenes (43). On the other hand, Empedocles (9), Anaxagoras (28), and Democritus (72) have nothing distinctive to say about it. As for smell, it does presuppose distance, but one that is also immediately suppressed through respiration. This is what the standard explanation amounts to in saying that it occurs “together with respiration” (Empedocles, 9, 22; Alcmaeon, 25). If this is true, we may be tempted to conclude that if sight a
nd hearing are the most interesting among the senses, this is not only because they are epistemologically rich and physiologically complex but also because more work is needed to explain how contact is possible in their cases.
Getting into more details would lead us too far afield. The point I would like to conclude with is of a more general nature. Topological explanations surely reflect a great deal of physiological interest. Physiology, as always in early Greek philosophy, is by itself of a philosophical nature, because it cannot be detached from a set of general principles that are ultimately ontological in scope. Empedocles and Anaxagoras, who in a sense are the two central figures of Theophrastus’ treatise, as they embody the opposition between two ideal types of explanations of cognition (through the similar, through the opposite), are paradigmatic in this respect too.
Like every other bit of Anaxagoras’ theory, his explanation of senseperception tells a story about difference, domination, and even violence. It is well-known that according to Anaxagoras, snow, which appears to be white, is black, since it is made of water (DK 59 A97). Sense discrimination is always one-sided, it only reveals what dominates in its object. But the discriminating power of perception would itself be impossible if we were not different from what we perceive. This is so to speak the material expression of the weakness of the senses, which operate within and thanks to the mixture that only nous, as the only unmixed entity (B12), can separate.42 If we can distinguish sweetness, this is by contrast with the sour that is in us. Perceptions will be more accurate, the stronger the contrast is. What is at stake in perception is a certain strength-ratio (27, 37). This explains the crucial role played by the size of the perceiving organs, and more generally of animals, in Anaxagoras’ theory. It also explains that, according to Anaxagoras, there is no sensation that is not painful. Even if we do not notice it under normal circumstances, both excessive perceptions and the need to sleep show the damage accumulated while exercising the senses.