Greek con once take us beyond the limits which we have prescribed § 7. The conception which the Greeks formed of the ception of conditions of psychology was not lacking in comprehenpsychological siveness. They saw that it demanded for its successful problem, as regards prosecution a thorough knowledge (a) of the stimulus of perception. perception; (b) of the organ of perception as well as of the whole organism; and (c) of the medium which somehow connects the object with the organ, and by the help of which the stimulus takes effect in quickening sensation so as to bring the object home 'to consciousness.' Thus a psychological interest not only excited them to physical inquiries but aroused them to investigations which have since culminated in anatomy, physiology, and histology. But they had only vague anticipatory conceptions, such as enabled them to put questions which they were utterly unable to answer, although upon the answers depended the progress of psychological knowledge. Thus for centuries this subject remained totally unprogressive. Any useful progress made by it in modern times has resulted chiefly from advances made in physiological and physical knowledge. If with all that biology, chemistry, and physics can do to help it forward, the most interesting questions of psychology are still unanswerable, or at least unanswered, it is easy to see how fruitless the most intelligent attempts of the ancients were doomed to be in dealing with such questions before these auxiliary sciences existed. 3 PART I. THE FIVE SENSES THE ANCIENT GREEK PSYCHOLOGY OF VISION Greek sense of § 1. THE speculations of the ancient Greeks as to the Ancient conditions of seeing, and the nature of the proper object of speculation vision, may be chosen to illustrate the strength or weakness as to the of their whole position in elementary psychology. The sight. capital of knowledge which they possessed respecting the facts of seeing was of the scantiest and most superficial kind. They knew (as the most ignorant person knows) that the eye is the organ of sight, and that without light the eye cannot see; that, besides light and the eye, an object is also necessary for vision; and that, moreover, the relationship of the eye to the organism, or certain parts of it, requires to be considered before seeing can be fully explained. Of most of the clear and fine distinctions marked by modern anatomy and physiology between the various parts of the visual apparatus the Greeks, from the time of Alcmaeon to that of Aristotle, were totally ignorant. They had not noticed the retina; they knew of the crystalline lens as an anatomical fact, but had not any notion of its refractive properties, or of the eye as an optical system. They were hopelessly ignorant of the mechanism and need of optical adjustment or accommodation. Such were their shortcomings in physiology, and consequently in the empirical psychology of vision. data of § 2. I. Almost all the early attempts at a theory of The chief vision agree in regarding the 'pupil' of the eye as a matter ancient of primary importance for visual function1. 1 The Greek kópŋ and Latin pupula, or pupilla, as meaning 'pupil,' are both named originally from the circumstance that an observer looking into a person's eye can see in the dark central spot an image of himself Greek of vision. psychology II. Another fact which greatly influenced this branch of study was that when the eyeball is pressed, or moved hastily, in darkness, a flash of light1 is seen within the eye. From this was drawn the conclusion that the eye has within it a native fire, and that on this native fire, not less than upon the image in the pupil, its faculty of vision somehow depends. III. A third fact which formed a basis of visual theory was that the interior of the eye is found to contain aqueous humours-roughly called water' by the Greeks. The functions of the retina being altogether unknown, and the optic nerves being perhaps known, but certainly not known in their true character, the primary business of the early psychologists who treated of vision seemed to be, to determine the parts played in vision by the image, the fire, and the water, respectively. As regards the assumed intra-ocular fire, the question was frequently agitated, whether its rays went forth from the eye as from a luminary, and (either by themselves or in combination with a column of light proceeding from the object) as it were apprehended the object of vision, and brought it within the purview of 'the soul'; or whether the fire merely lurked within the periphery of the eye, and there seized the image which, coming to it from outside, was reflected in the aqueous interior, as if in a mirror. The seat of the inner fire was the pupil, which, at least from the time of Empedocles, was identified generally with the 'lens.' With these facts before us we shall be better prepared to understand the purport of the extracts which are to follow. We reflected there. This is dwelt upon by Plato (?) Alcib. i. 132 E kai Tậ ὀφθαλμῷ ᾧ ὁρῶμεν ἔνεστί τι τῶν τοιούτων (sc. τῶν κατόπτρων); . . . ἐννενόηκας οὖν ὅτι τοῦ ἐμβλέποντος εἰς τὸν ὀφθαλμὸν τὸ πρόσωπον ἐμφαίνεται ἐν τῇ τοῦ κατ ̓ ἀντικρὺ ὄψει ὥσπερ ἐν κατόπτρῳ, ὃ δὴ καὶ κόρην καλοῦμεν, εἴδωλον ὄν τι τοῦ ἐμβλέποντος. This image of B mirrored in A's eye and seen there by B, was by many regarded as the essential objective equivalent of the psychic fact that A sees B, just as if it were an image on A's retina, not in the pupil of A's eye. This early view of kóρn was, however, soon modified. It came to represent what is now called the 'lens.' Cf. Theophr. de Sens. § 36. 1 The Greeks knew nothing of pressure of the eyeball serving as retinal stimulus, and so causing this sensation of light. shall consider these according as they bear upon the organ (or function), the medium, or the object of vision. It is to be noticed that Alcmaeon, with whom we begin, has left us no information on what he conceived to be the nature of the medium or the object. His recorded views are concerned only with the visual organ, its functions, and its relationship to the organism as a whole. Alcmaeon of Crotona. of Cro- of seeing. § 3. 'Seeing takes place,' says Alcmaeon1, 'by reflexion Alcmaeon in the diaphanous element.' 'Alcmaeon of Crotona 2 held that the eyes see through the environing water. That [each the sense eye] contains fire is, indeed, manifest, for a flash takes place within it when it receives a stroke. It is with the glittering and diaphanous element, however, that it sees, whenever this reflects an image (åvrɩþaívŋ), and it sees better in proportion to the purity of this element 3." Chalcidius tells us that Alcmaeon was the first to practise dissection, and that to him, as well as (long afterwards) to Callisthenes and Herophilus, many important e. 1 Stob. Ecl. Phys. i. 52 (Diels, Dox., p. 404, Vors. p. 104). I have translated Diels' (Dox. proll. p. 223) suggestion ȧvriλaμyiv for MS.' avriλniv = 'apprehension' by the diaphanous element, which still brings us to the idea of reflexion. 'Avτíλaμ&iv=reflexion, corresponds to the ȧvripaivŋ of Theophr. § 26; see next extract. To ascribe 'apprehensive' power to the diapavés within the eye is quite out of keeping with the doctrine of Alcmaeon, nor is he likely to have employed the term avrínyis. Indeed it surprises one to find even rò diapavés—a distinctively Aristotelean word in this connexion-ascribed to him. 2 Theophr. de Sens. § 26 (Diels, Vors., p. 104). 3 Wachtler, de Alc. Crot. (Teubner, 1896), p. 49, refers To σrißovti here to the fire and râ diapaveî to the water within the eye. But oriλßeiv is not often found used of the gleam of fire (which would rather be λáμm), whereas it is regularly used of lustre, and of the glittering of water. Cf. Arist. 370 18 φαίνεται τὸ ὕδωρ στίλβειν, and 561* 32 ὑγρὸν ἔνεστι λευκὸν καὶ ψυχρόν, σφόδρα στίλβον. Both participles should, notwithstanding the repetition of the article, be referred to the same thing, viz. the diaphanous' element in which the image is said to be reflected. C. Bäumker (Arist. Lehre von den äussern und innern Sinnesvermögen, p. 49) notices that in the passage above translated, the words ὁρᾶν δὲ τῷ στίλβοντι καὶ τῷ διαφανεῖ form an iambic trimeter. * In Plat. Tim., p. 279, ed. Wrobel, pp. 340-1, ed. Meursius. The intra ocular fire and the discoveries respecting the anatomy of the eye and the optic nerves are due. It is not possible, however, to determine from the words of Chalcidius how much of the anatomical knowledge of which he speaks was discovered by Alcmaeon, and how much by the others; nor can much weight be assigned to the authority of this commentator on such matters. But, according to the Hippocratean treatise Περὶ Σαρκῶν (or Αρχών), the connexion between eye and brain is formed by a 'vein' passing from the membrane which covers the latter to each of the two eyes. Through this 'vein' the viscous substance of the brain is said to prolong itself into the eyes, where it forms the transparent membranes which cover the eyes. In this the light and all bright objects are reflected, and by this reflexion we see. Things, again, are seen because they have brightness, and can therefore be reflected by the transparent membrane of the eye. This fact of reflexion, according to the Pythagorean theory1, is accomplished by 'a visual ray' from eye to object, which reaching the object doubles back again to the eye, like a forearm outstretched and then bent back again to the shoulder 2. The above pseudo-Hippocratean tract may (as Siebeck says) really present us with an account of Alcmaeon's theory of vision. The membranes, of which there are many protecting the visual organ, are diaphanous like the organ itself. By means of this quality of diaphanousness it reflects (avravyeî) the light and all illuminated objects; accordingly it is by means of this, which so reflects, that the visual organ (rò ópéov) sees 3.' ་ § 4. According to Alcmaeon, therefore, it would seem that vision is effected by the 'image,' and by rays which issue from within and pass outwards through the water; that flected in these rays emanate from a fire within the eye; as if the co-operate glistening and diaphanous element in the eye were merely image re the water 1 It is not improbable that Alcmaeon was to some extent influenced by the Pythagorean teaching: vide Arist. Met. i. 5. 986a 29; Siebeck, Geschichte der Psychologie, i. 1, pp. 103-106. 2 Cf. Plut. Epit. iv. 14; Diels, Dox., p. 405. 3 Cf. Hippocr. viii. 606 L.; Diels, Vors., p. 104. For ȧvτavyeî cf. Eur. Or. 1519, and ȧvrηúyei σéλas, Stob. Flor. ii. p. 392 (Teub.). |