Ptolemy's Theory of Visual Perception: An English Translation of the OpticsThis is a print on demand Publication. This is a reprint, this is not an original. Contents: Introduction; Ptolemy: A Biographical Sketch; The "Optics": A Biographical Sketch; An Overview of the "Optics"; The Historical Influence of the "Optics"; English Translation; & Bibliography. The English translation of this text is based upon Albert Lejeune's critical Latin text of 1956, which was reprinted in the 1990s along with a French translation & supplementary annotations. Illus. |
Common terms and phrases
according Accordingly actually analysis appear apprehended assume axes axis base bodies cathetus cause circle clear color common concave concave mirrors continuous convex course demonstrated depends determined difference direct directly discussion distance drawn dropped equal angles Euclid evident experiment extended face fact fall farther figure follows formed given greater hand happens illusion incident intersect L'Optique larger Latin Lejeune let line lies light means medium mirror Moreover motion move nature normal observed occurs Optics passing pegs perceived perception physical plane position possible principles proper properties Ptolemy Ptolemy's reason reflected at equal reflection refraction represent respect resulting seems seen sense shape side sight single smaller sometimes sort sources straight line surface THEOREM theory things tion translation visible object vision visual cone visual flux visual ray whereas
Popular passages
Page 52 - He should be a man of letters, a skillful draughtsman, a mathematician, familiar with historical studies, a diligent student of philosophy, acquainted with music; not ignorant of medicine, learned in the responses of jurisconsults, familiar with astronomy and astronomical calculations....
Page 54 - ... them, I thought it better to omit the matter altogether. But afterward I dreamed that I was being censured because I was unjust to the most godlike of the instruments and was behaving impiously toward the creator in leaving unexplained a great work of his providence for animals, and so I felt impelled to take up again what I had omitted and add it to the end of this book.
Page 65 - The disciples of Plato contributed not a little to the advancement of optics, by the important discovery they made, that light emits itself in straight lines, and that the angle of incidence is always equal to the angle of reflection. Plato terms colours " the effect of light transmitted from bodies, the small particles of which were adapted to the organ of sight" This seems precisely what sir Isaac Newton teaches in his " Optics,
Page 54 - I have explained nearly everything pertaining to the eyes with the exception of one point which I had intended to omit lest many of my readers be annoyed with the obscurity of the explanations and the length of the treatment. For since it necessarily involves the theory of geometry and most people pretending to some education not only are ignorant of this but also avoid those who do understand it and are annoyed with them, I thought it better to omit the matter altogether. But afterward I dreamed...
Page xi - The editors wish to acknowledge the generous support of the National Endowment for the Humanities (Ref: GB-20081-86), and especially the encouragement of the Bicentennial Division and the Division of Public Programs.
Page 19 - Similar evidence is supplied by the more natural of the branches of mathematics, such as optics, harmonics, and astronomy. These are in a way the converse of geometry. While geometry investigates natural lines but not qua natural, optics investigates mathematical lines, but qua natural, not qua mathematical.
Page 75 - ... for touch, savors for taste, sounds for hearing, and odors for smell [Aristotle, On the Soul 2.6 (418a11-14)]. But among the things that are common to the senses according to the origin of nervous activity [the hegemonikon: see Chapter 12], sight and touch share in all except color, for color is perceived by no sense but sight. Thus, color must be the proper sensible for sight, and that is why color is taken to be what is primarily visible after light. In view of this...
Page 49 - Aristotle's theory of the rainbow, see Carl B. Boyer, The Rainbow: From Myth to Mathematics (New York, 1959), pp.
Page 83 - ... together from our eyes on that [new] object are not correspondingly arranged, then that same object will be seen at two places. But when we close or cover either of our eyes, then the image in one of the two locations will immediately disappear, while the other will persist, [and the image that persists is] sometimes the one directly in front of the covered eye and sometimes the one directly in front of the other eye. This point will be easily understood if we try to explain it in the following...
Page 74 - Optics 2.13-14 [color] A sole proper sensible ["thing sensed"] can be found that is appropriate to each of the senses; eg, the quality of "resisting the hand" for touch, savors for taste, sounds for hearing, and odors for smell [Aristotle, On the Soul 2.6 (418a11-14)].