A Essay Towards a New Theory of Vision   By: George Berkeley (1685-1753)

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1 Design 2 Distance of itself invisible 3 Remote distance perceived rather by experience than by sense 4 Near distance thought to be perceived by the ANGLE of the OPTIC AXES 5 Difference between this and the former manner of perceiving distance 6 Also by diverging rays 7 This depends not on experience 8 These the common accounts, but not satisfactory 9 Some IDEAS perceived by the mediation of others 10 No IDEA which is not itself perceived, can be the means of perceiving another 11 Distance perceived by means of some other IDEA 12 Those lines and angles mentioned in optics, are not themselves perceived 13 Hence the mind does not perceive distance by lines and angles 14 Also because they have no real existence 15 And because they are insufficient to explain the phenomena 16 The IDEAS that suggest distance are, 1st, the sensation arising from the turn of the eyes 17 Betwixt which and distance there is no necessary connection 18 Scarce room for mistake in this matter 19 No regard had to the angle of the OPTIC AXES 20 Judgment of distance made with both eyes, the result of EXPERIENCE 21 2ndly, Confusedness of appearance 22 This the occasion of those judgments attributed to diverging rays 23 Objection answered 24 What deceives the writers of optics in this matter 25 The cause why one IDEA may suggest another 26 This applied to confusion and distance 27 Thirrdly, the straining of the eye 28 The occasions which suggest distance have in their own nature no relation to it 29 A difficult case proposed by Dr. Barrow as repugnant to all the known theories 30 This case contradicts a received principle in catoptrics 31 It is shown to agree with the principles we have laid down 32 This phenomenon illustrated 33 It confirms the truth of the principle whereby it is explained 34 Vision when distinct, and when confused 35 The different effects of parallel diverging and converging rays 36 How converging and diverging rays come to suggest the same distance 37 A person extreme purblind would judge aright in the forementioned case 38 Lines and angles, why useful in optics 39 The not understanding this, a cause of mistake 40 A query proposed, by Mr. Molyneux in his DIOPTRICS, considered 41 One born blind would not at first have any IDEA of distance by sight 42 This not agreeable to the common principles 43 The proper objects of sight, not without the mind, nor the images of any thing without the mind 44 This more fully explained 45 In what sense we must be understood to see distance and external things 46 Distance, and things placed at a distance, not otherwise perceived by the eye than by the ear 47 The IDEAS of sight more apt to be confounded with the IDEAS of touch than those of hearing are 48 How this comes to pass 49 Strictly speaking, we never see and feel the same thing 50 Objects of SIGHT twofold, mediate and immediate 51 These hard to separate in our thoughts 52 The received accounts of our perceiving magnitude by sight, false 53 Magnitude perceived as immediately as distance 54 Two kinds of sensible extension, neither of which is infinitely divisible 55 The tangible magnitude of an OBJECT steady, the visible not 56 By what means tangible magnitude is perceived by sight 57 This further enlarged on 58 No necessary connection between confusion or faintness of appearance, and small or great magnitude 59 The tangible magnitude of an OBJECT more heeded than the visible, and why 60 An instance of this 61 Men do not measure by visible feet or inches 62 No necessary connection between visible and tangible extension 63 Greater visible magnitude might signify lesser tangible magnitude 64 The judgments we make of magnitude depend altogether on experience 65 Distance and magnitude seen as shame or anger 66 But we are prone to think otherwise, and why 67 The moon seems greater in the horizon than in the meridian 68 The cause of this phenomenon assigned 69 The horizontal moon, why greater at one time than another... Continue reading book >>