Observers, objects, and the embedded eye; or, seeing and knowing in ptolemy and galen

ISIS

Volumn 98, Issue 3, 2007, Pages 447-467

  Lehoux, Daryn ^a  

^a UNIVERSITY OF MANCHESTER   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

CULTURAL ANTHROPOLOGY; EYE; HISTORY; HUMAN; PERCEPTION; PHYSIOLOGY; REVIEW; VISION; VISUAL SYSTEM FUNCTION;

CULTURE; EYE; HISTORY, ANCIENT; HUMANS; OCULAR PHYSIOLOGY; PERCEPTION; PHYSIOLOGY; VISION;

EID: 35548954786     PISSN: 00211753     EISSN: 15456994     Source Type: Journal    
DOI: 10.1086/521152     Document Type: Review

References (129)

1. For this I can thank Kevin McNamee.
2. Ian Hacking, Representing and Intervening (Cambridge: Cambridge Univ. Press, 1983), puts these issues under the umbrella of styles of reasoning;
3. Nelson Goodman, Ways of Worldmaking (Indianapolis: Hackett, 1978), frames it as a question of worlds;
4. Paul Feyerabend, Against Method: Outline of an Anarchistic Theory of Knowledge (London: Humanities, 1975), tries to locate it under the rubric of incommensurability;
5. Michel Foucault, Les mots et les choses: Un archéologie des sciences humaines (Paris: Gallimard, 1966), refers to epistemes;
6. and J. G. A. Pocock, Virtue, Commerce, and History (Cambridge: Cambridge Univ. Press, 1985), speaks of discourses.
7. On these "currents" see, e.g., Jutta Kollesch, "Galen und the Zweite Sophistik," in Galen: Problems and Prospects, ed. Vivian Nutton (London: Wellcome Institute for the History of Medicine, 1981);
8. and Heinrich von Staden, "Galen and the 'Second Sophistic,'" in Aristotle and After, ed. Richard Sorabji (London: Institute of Classical Studies, 1997), pp. 33-54.
9. Throughout this essay, the careful reader will notice that "sensation" and "perception" are being used virtually synonymously. Neither Ptolemy nor Galen had access to Bertrand Russell's very influential distinction between sensation and perception in The Analysis of Mind (London: Allen & Unwin, .1921). Indeed, the kinds of psychological burdens that Russell is flagging in perception as interposing and imposing on sensation only become really problematized (and so only begin to need systematic explanation) with, the advent of professional psychology in the nineteenth, century.
10. There are a few exceptions, however: Anthony Long, "Ptolemy: Epistemology for the Scientist," in The Criterion of Truth, ed. Pamela Huby and Gordon Neal (Liverpool: Liverpool Univ. Press, 1989), pp. 151-178;
11. Paola Manuli, "Claudio Tolomeo: Il criterio e il principio," Rivista Critica di Storia della Filosofia, 1981, 35:64-88;
12. and Giorgio Cardona, "Tolomeo e Galeno," in Lafilosofia ellenistica e la patristica Christiana dal III secolo A.c. al V secólo D.C., ed. Mario del Pra (Milan: Vallardi, 1975), pp. 229-249.
13. Both Galen and Ptolemy are often classed by modern readers as philosophical eclectics. Although the word is handy, it is not uncontroversial in this particular instance, and, at the very least, I would certainly not want "eclectic" to be understood as pejorative. On Galen's eclecticism see esp. Michael Frede, "On Galen's Epistemology," in Galen, ed. Nutton (cit. n. 3), pp. 65-86;
14. R. J. Hankinson, "Galen's Philosophical Eclecticism," Aufstieg und Niedergang der Römischen Welt, 2nd Ser., 1992, 36(5):3505-3522;
15. Pierluigi Donini, "Galeno e la filosofia," ibid., pp. 3484-3505;
16. and Heinrich von Staden, "Body, Soul, and Nerves: Epicurus, Herophilus, Erasistratus, the Stoics, and Galen," in Psyche and Soma: Physicians and Metaphysicians on the Mind-Body Problem from Antiquity to the Enlightenment, ed. John P. Wright and Paul Potter (Oxford: Clarendon, 2000), pp. 79-116.
17. On Ptolemy's see Long, "Ptolemy";
18. and A. Mark Smith, Ptolemy's Theory of Visual Perception: An English Translation of the Optics (Transactions of the American Philosophical Society, 86[2]) (Philadelphia: American Philosophical Society, .1996), pp. 17-18.
19. On eclecticism, in general see, e.g., Donini, "The History of the Concept of Eclecticism," in The Question of "Eclecticism," ed. J. M. Dillon and A. A. Long (Berkeley: Univ. California Press, 1988), pp. 15-33.
20. Philosophers are wont to characterize representational accounts of perception in contrast to something called "common sense" realist accounts, but I think here they generally underestimate the common-sense nature of the representational accounts, which are, if anything, far more pervasive and deeply rooted (at least since Locke).
21. See, e.g., Hilary Putnam., The Threefold Cord (New York: Columbia Univ. Press, 1999);
22. and John Foster, The Nature of Perception (Oxford: Oxford Univ. Press, 2000).
23. Lorraine Daston and Kelley Wilder have pointed out to me that the line of argument here got a kind of second life in the nineteenth and twentieth centuries in debates about the nature of photography. These debates run on two different (if overlapping) planes: (1) Is photography representational or (merely) causal? If only causal, can it be art? (2) What is the nature and value of photographic evidence versus other kinds of evidence? Both of these issues put the question of human agency and mediation between object and image front and center (and situated at just the point where Scepticism would drive the wedge in for the ancient problem, of perception). Much of the debate on photography (as Ted Cohen, "What's Special about Photography," Monist, 1988, 71: 292-305, very rightly points out) sees the camera as implausibly autonomous
24. (see also Joel Snyder and Neil Walsh Allen, "Photography, Vision, and Representation," Critical Inquiry, 1975, 2:143-169;
25. contrast Kendall Walton, "Transparent Pictures: On the Nature of Photographic Realism," ibid., 1984, 11:246-277). Take Bazin's very influential and highly provocative framing: "L'originalité de la photographie par rapport à la peinture réside donc dans son objectivité essentielle. Aussi bien, le groupe de lentilles qui constitue l'oeil photographique substitué àl'oeil humain s'appelle-t-il précisément 'l'objectif.' Pour la première fois, entre l'objet initial et sa représentation, rien ne s'interpose qu'un autre objet Pour la première fois, une image du monde extérieur se forme automatiquement sans intervention créatrice de l'homme, selon un déterminisme rigoureux."
26. André Bazin, "Ontologie de l'image photographique" (.1945), rpt. in Qu'est-ce que le cinéma? (Paris: Éditions du Cerf, 1975), pp. 9-17.
27. In philosophical aesthetics, this same line of thought led Roger Scruton ("Photography and Representation," Crit. Inq., 1981, 7:577-603)
28. and Walton to argue that photographs (being causal) were not representations, which seemed to many to mean that they could not be art. Attempts to salvage representation in photography (e.g., Donald Brook, "Painting, Photography, and Representation," Journal of Aesthetics and Art Criticism, 1983, 42:171-180
29. -misreading Nelson Goodman, Languages of Art [Indianapolis: Hackett, 1968]) have unfortunately sometimes relied on interpreting "representation" linguistically (far too limiting!),
30. a trap that Scruton thankfully avoids, as does Gregory Currie, "Photography, Painting, and Perception," J. Aesthet. Art Crit., 199.1, 49:23-29. Cohen is still, I think, the best way out of this whole quagmire. Here I cannot resist the urge to paraphrase the NRA: cameras do not shoot people; people shoot people.
31. See, e.g., A. Mark Smith, Ptolemy and the Foundations of Ancient Mathematical Optics: A Source-Based Guided Study (Transactions of the American Philosophical Society, 89[3]) (Philadelphia: American Philosophical Society, 1999);
32. Gérard Simon, Le regard, l'être, et l'apparence dans l'optique de l'antiquité (Paris: Éditions du Seuil, 1988);
33. and David Lindberg, Theories of Vision from al-Kindi to Kepler (Chicago: Univ. Chicago Press, 1976).
34. To be sure, the ways in which the radiation passes this information back, do usually depend on light as an actor, and this will complicate or at least qualify the use of the word "extramission." See Smith Ptolemy and the Foundations of Ancient Mathematical Optics, p. 23f. Here and throughout, "radiation" is used in its root sense to refer only to things that travel in straight lines-i.e., as mathematical rays-rather than in the modern physical sense.
35. The Epicureans are perhaps the most obvious example of philosophers who are not extramissionists, but Plato and Aristotle, as well as most of the Presocratics for whom we have any information, cannot be counted as extramissionists either. Nevertheless, Mary Beagon has pointed out to me that Democritus's explanation of the Evil Eye uses a kind of extramission of malign particles to account for the effect (something similar can be found in Plutarch, Moralia 680b-682b), although this is not an explanation of vision per se.
36. See Mary Beagon, trans., The Elder Pliny on the Human Animal: Natural History Book VII (Oxford: Clarendon, 2005), p. 139f.
37. For a good general overview of the different optical theories on offer in antiquity see the introduction to Smith., Ptolemy and the Foundations of Ancient Mathematical Optics.
38. Finally, A. Mark Smith, "The Psychology of Visual Perception in Ptolemy's Optics," Isis, 1988, 79:188-207, questions Lindberg's idea that there was a distinct "philosophical tradition" in optics.
39. Pseudo-Aristotelian Problems 959a2f;
40. and Galen, Deplacitis Hippocratis et Platonis
41. (hereafter abbreviated as De plac. Hipp, et Plat.) 7.4. 11f. Here and elsewhere, all translations into English are my own.
42. This last group of objections to intromission is conditioned by the fact that the main intromissionist theory available in antiquity was Epicurean, where what we perceive are films or images of atoms that peel off of objects in every direction. See esp. De plac. Hipp, et Plat. 7.7.8f.
43. Aristotle, Metaphysica 373a33f. Later commentaries on this passage identify the man as a certain Antipheron (Olympiodorus says he is from Tarentum, Alexander that he is from. Oreus). Aristotle does elsewhere refer by name to a certain Antipheron. of Oreus as being subject to a particular kind of madness that had him believing phantasms were real (De memoria et reminiscentia 451a8) but says nothing there about his eyesight, poor or otherwise. Michael of Ephesus, in the eleventh or twelfth century A.D., explicitly tries to bridge the gap by pointing out that Aristotle's tale about the anonymous self-seeing man was really about the Antipheron of Oreus mentioned in the De mem. (In parva naturalia commentaria 17.30). Given the root meaning of the Greek name Antipheron ("one who goes in the opposite direction"), however, it is hard not to see the association with the man whose reflection accompanied him everywhere as apocryphal.
44. On tropes in the sense I mean here see Daryn Lehoux, "Tropes, Facts, and Empiricism," Perspectives on Science, 2003, 11:326-345.
45. Ptolemy, Optics
46. (hereafter abbreviated as Opt.) 2.9.
47. Aristotle, De sensu and De anima.
48. Galen's objection is at De plac. Hipp, et Plat. 7.7.10f.
49. A. Mark Smith, "The Physiological and Psychological Grounds of Ptolemy's Visual Theory: Some Methodological Considerations," Journal of the Behavioral Sciences, 1998, 34:231 -246;
50. Alexander Jones, "Ptolemy's Mathematical Models and Their Meaning," in Mathematics and the Historian's Craft: The Kenneth O. May Lectures, ed. Glen Van Brummelen and Michael Kinyon (New York: Springer, 2005), pp. 23-42;
51. and Bernard R. Goldstein, "The Arabic Version of Ptolemy's Planetary Hypotheses," Transactions of the American Philosophical Society, 1967, 57:4-12.
52. Euclid's rays are discrete, and objects can fall between individual rays when they are small or distant enough. Ptolemy argues specifically against this theory, preferring a visual continuum.
53. Smith, "Psychology of Visual Perception in Ptolemy's Optics" (cit. n. 11), p. 196, wants to see the flux as Stoic pneuma, the same substance Galen will have emanating from the eye, but this relies on a chain of inference that is not nearly so solid as I would like: that Ptolemy's virtus regitiva can be identified as equivalent to the Stoic hegemonikon Iam partial to accepting; but to move from, there to the idea that Ptolemy's flux must therefore also be Stoic is to overburden the initial equivalence unduly. In discussing a dream. I had, for example, I can easily use a phrase that is more or less equivalent to "my subconscious" without implying that I accept any other baggage of Freudian psychology (e.g., "my Oedipal complex").
54. Galen offers a magisterial argument for the physicality of the soul in Quod animi mores corporis temperamenta sequuntur, even though he is there and elsewhere cautious about genuinely committing to the idea.
55. See Martino Menghi and Mario Vegetti, Le passioni e gli errori del' anima (Venice: Marsilio, 1984);
56. R. J. Hankinson, "Galen's Anatomy of the Soul," Phronesis, 1991, 36:197-233;
57. Von Staden, "Body, Soul, and Nerves" (cit. n. 6);
58. and Teun Tieleman, "Galen's Psychology," in Galien et la philosophie, ed. Jonathan Barnes and Jacques Jouanna (Geneva: Hardt, 2003), pp. 131-169.
59. Ǒpyavov is also the origin of the English. Organon, which collectively refers to Aristotle's logical books (where logic is conceived of as a basic instrument for doing philosophy), and hence by extension also Bacon's Novum organum.
60. On Galen's definition of the word see Galen, On the Usefulness of the Parts of the Body, trans. Margaret Tallmadge May (Ithaca, N.Y: Cornell Univ. Press, 1968), p. 67 n 3.
61. David Langslow has reminded me here of how rich a source of metaphor warfare is in pathology, anatomy, and therapeutics.
62. Aristophanes, Wasps 1190f.
63. On Galen's definition(s) of Nature see esp. Jacques Jouanna, "La notion de nature chez Galien," in Galten et la philosophie, ed. Barnes and Jouanna (cit. n. 21), pp. 229-268;
64. and Fridolf Kudlien, "Galen's Religious Belief," in Galen, ed. Nutton (cit. n. 3), pp. 117-130.
65. See also Galen, On the Usefulness of the Parts of the Body, trans. May (cit. n. 22), p. 10f.;
66. R. J. Hankinson, "Galen and the Best of All Possible Worlds," Classical Quarterly, 1989, 39:206-227;
67. and (albeit briefly) Vivian Nutton, Ancient Medicine (New York: Routledge, 2004), pp. 234-235.
68. Jackie Pigeaud, "Les problèmes de la création chez Galien," in Galen und das hellenistische Erbe, ed. J. Kollesch and D. Nickel (Stuttgart: Steiner, 1993), pp. 87-103,
69. is tangentially useful. On divine providence with respect to vision in particular see De usu partium 10;
70. and De plac. Hipp, et Plat. 7.5.13f.
71. In using the word "constitution," I want to underscore Galen's emphasis on the combination of the physical makeup of an organ, its particular balance of the elements, its geometrical shape, and the arrangement of its parts (cf. De usu partium 1.9).
72. On the complex relationships between Galen's teleology and his materialism see P. N. Singer, "Levels of Explanation in Galen," Cl. Quart., 1997, 47:525-542;
73. and Hankinson, "Galen and the Best of AU Possible Worlds" (cit. n. 25). In many ways, the questions raised by this issue are profoundly relevant to any reading of De usu partium in particular, where Galen is very explicitly running between a hands-on detailed anatomical study, a teleological paean to a benign and wise creator, and, from, time to time, a physical (elemental) explanation of the composition of organs and parts.
74. The exact details of the precise role oipneuma are not always as clear as we might like, however.
75. See Julius Rocca, Galen on the Brain (Leiden: Brill, 2003), p. 66;
76. Leonard G. Wilson, "Erasistratus, Galen, and the Pneuma," Bulletin of the History of Medicine, 1959, 33:293-314;
77. G. E. R. Lloyd, Revolutions of Wisdom (Berkeley: Univ. California Press, 1987), p. 213;
78. and Von Staden, "Body, Soul, and Nerves" (cit. n. 6).
79. De usu partium 8.6.
80. He has something like this clearly in mind when he points out that alterations in atmospheric air, which is a continuum, should happen, in an instant, De plac. Hipp, et Plat. 7.5.7.
81. De plac. Hipp, et Plat. 7.5.5, 7.5.32, 7.4.18.
82. De plac. Hipp, et Plat. 7.5.4.1, 7.7.20.
83. For the Chrysippean models see Stoicorum veterum fragmenta 2.232f.
84. Opt. 2.7.
85. I borrow the translation "corporeity" from Smith, Ptolemy's Theory of Visual, Perception (cit. n. 6), p. 71 n 1;
86. he clarifies thus: "I have rendered corpus as 'corporeity' to indicate that it is not so much body as the fact that something is a body that is apprehended by sight." Aristotle's view that the proper sensible of sight is color appears at De anima 418all-14.
87. See Daryn Lehoux, "Laws of Nature and Natural Laws," Studies in History and Philosophy of Science, 2006, 37:527-549, for my argument.
88. Smith, "Psychology of Visual Perception in Ptolemy's Optics" (cit. n. 11), p. 200f., has argued for a considerable borrowing of particular details of Ptolemy's analysis from Aristotle, but-as in the case of Smith's views on Stoic influence-I want to be more cautious.
89. Opt. 2.16, 2.18 ("ex diuersitatibus quidem quantitatis uidetur res magis, quando plus incidit super earn, claritas uisus, aut quando lumen plus cadit super earn").
90. Opt. 2.23 (quotation), 2.63.
91. See Ptolemy, On the Criterion and Hegemonikon
92. (hereafter abbreviated as Crit.) 10.3, 11.1;
93. and Opt. 2.23.
94. De usu partium 8.6;
95. and De plac. Hipp, et Plat. 7.6.10. "Shakes hands with" is an admittedly imperfect rendering of a very difficult sense to translate. The adjective by itself means "well known," "familiar."
96. De plac. Hipp, et Plat. 7.5.42-44. Taste may appear to be a slight exception here, where its has to do with receptivity to certain properties of its objects rather than to the objects themselves; so, instead of being "food-like," it is said to be moist and "sponge-like". This is elaborated on a little later (7.6.22), where Galen explains that the objects of taste are moist, from which we can see that the moistness of the organ of taste is again in a like-to-like correspondence with its objects.
97. De plac. Hipp, et Plat. 7.5.13.
98. See Georgius Goetz, Thesaurus glossarum emendatarum (Leipzig: Teubner, 1899).
99. Among the Greek words that Cicero renders as "genus" in his translation of Plato's Timaeus is the Greek (Cie. Tim. 21 = Pl. Tim. 35a).
100. Pyrrhonism is the stronger of the two ancient varieties of Scepticism, the other being Academic Scepticism (the school to which Cicero and Plutarch subscribed), which, although worried about the reliability of the senses, did not take it as proven that they told us nothing about the world.
101. See e.g., Pyrrhoniae hypotyposes 3.38f., 1.35f. The word for "apprehensible" Sextus uses is, "graspable," which is a technical term, in Hellenistic epistemology that is often used to refer to perception but also included cognitive "grasping" (perhaps in a similar way to how the English "I see" also means "I understand").
102. The "modes" are collected and discussed most fully in Julia Annas and Jonathan Barnes, The Modes of Scepticism (Cambridge: Cambridge Univ. Press, 1985).
103. For the centrality of the criterion in Hellenistic epistemology, and its relation to debates between dogmatic schools and Sceptics, see Long, "Ptolemy" (cit. n. 5).
104. Long, "Ptolemy," notes that some of Ptolemy's categories are shared by another of the second century's great intellects, Sextus Empiricus-specifically, the middle three categories of instrument, agent, and means (although Sextus may be using category [4], means, with a slightly different emphasis than Ptolemy does). Long sees the two accounts as virtually identical, but Sextus's use of the application of sense impressions, in slot (4), where Ptolemy talks of dialectic as the means by which the intellect judges, is more clearly rooted in a particular set of debates centered on Stoicism. There are family resemblances between the two accounts, but it is difficult to see how exactly to map Sextus's version onto Ptolemy's very precisely.
105. Recall that Galen had also used a metaphor from proportion theory to compare the relationship between the brain and psychic pneuma to that between the eye and worldly pneuma: De plac. Hipp, et Plat. 7.5.32. Although similar in kind to Ptolemy's analogy, it differs insofar as it breaks down Ptolemy's categories 1-3 differently, inserting two intermediary objects between 1 and 3, and Galen does not reify their relationship in the same way as Ptolemy does.
106. Opt. 2.22.
107. Crit. 8, 2.4.
108. On the Stoic understanding of phantasia see Anthony Long, "Stoic Psychology," in The Cambridge History of Hellenistic Philosophy, ed. Keimpe Algra et al. (Cambridge: Cambridge Univ. Press, 1999), pp. 560-584, on pp. 572-580.
109. Long uses "impression" as his translation of "phantasia" produced by sensation but does in other contexts offer "representation" as another translation, which could be seen as conflicting with my nonrepresentational reading of Ptolemy if it could be shown that Ptolemy is using "phantasia" in a strictly Stoic sense. Unfortunately, "phantasia" itself is a common term, in Hellenistic accounts of perception, and Ptolemy's use of it is gray enough not to allow us to decide to what extent he may be committing to a Stoic view in particular here. Finally, I am not certain that "phantasia" as a blanket term in Stoicism for something like "the objects of thought" would be precluded from sometimes being representational (as in memory) and sometimes being nonrepresentational (as in perception).
110. Crit. 9.6 (on the infallibility of the criterion forjudging), 11;
111. and Opt. 2.84f., 2.126f.
112. As Smith has remarked, "it would be fair to say that Ptolemy's ulterior purpose in the Optics as a whole is to correct such misjudgments by explaining them, away":
113. Smith., Ptolemy and the Foundations of Ancient Mathematical Optics (cit. n. 9), p. 40.
114. There is a lovely ambiguity in this regard at Opt. 2.83: "we should draw distinctions between illusions . . . in order that we can solve doubts that come up in investigations de scientia opticorum." Does this mean that we can solve doubts that come up in investigations concerning the science of optics or that we can solve doubts that come up in investigations by means of the science of optics?
115. Crit. 10.5-6;
116. and Opt. 2.73.
117. The precise correspondence between pneuma and consciousness is left open in Galen. Nevertheless, it is clear that consciousness depends on pneuma and intelligence on the quality of the pneuma: De usu partium 7.13.
118. Galen, De animi cuiuslibet peccatomm dignotione et cumtione 6.
119. Ptolemy is explicit that judgment, insofar as it uses language, is representational, but sense perception itself is causal.
120. For accounts of this position see, e.g., P. F. Strawson, "Perception and Its Objects," in Perception and Identity: Essays Presented to A. J. Ayer, with His Replies, ed. G. F. Macdonald (Ithaca, N. Y: Cornell Univ. Press, 1979), pp. 4.1-60;
121. and Putnam, Threefold Cord (cit. n. 7), although why Putnam claims that a causal account of perception should be "wholly incompatible" with, what he calls natural realism is opaque to me, unless it rests on his (unwarranted) assumption that causal theories are sense-data theories (pp. 12, 22)-
122. here contrast Fred Dretske, "Perception," in Cambridge Dictionary of Philosophy, ed. Robert Audi (Cambridge: Cambridge Univ. Press, 1995), p. 657.
123. In a different tradition, but making at least sympathetic points, see James J. Gibson, The Senses Considered as Perceptual Systems (Boston: Houghton-Mifflin, 1966).
124. Crit. 9.2. We can also experience when we are not thinking.
125. De plac. Hipp, et Plat. 2.1.1.
126. To be fair, it is not our scientific method, but it can be argued that it is a scientific method. For the translation. see Phillip de Lacy in Galen, De plac. Hipp, et Plat.;
127. and Teun Tieleman, Galen and Chrysippus: Argument and Refutation in the De Placitis Books II-III (Utrecht: Dept. Philosophy, Utrecht Univ., 1992).
128. De plac. Hipp, et Plat. 2.3.8.
129. Galen, Prognosis 98.5.