324 The sceptical objections to the trustworthiness of the senses, proposed by the Eleatics and others, referred to by Descartes in his _Meditations_, and by Malebranche in the First Book of his _Recherche_, may have suggested the ill.u.s.trations in this section.
Cf. also Hume"s Essay _On the Academical or Sceptical Philosophy_.
The sceptical difficulty is founded on the a.s.sumption that the object seen at different distances is the _same visible object_: it is really different, and so the difficulty vanishes.
325 Here Berkeley expressly introduces "touch"-a term which with him includes, not merely organic sense of contact, but also muscular and locomotive sense-experience. After this he begins to unfold the ant.i.thesis of visual and tactual phenomena, whose subsequent synthesis it is the aim of the _New Theory_ to explain. Cf.
_Principles of Human Knowledge_, sect. 43-_Theory of Vision Vindicated_, sect. 22 and 25. Note here Berkeley"s reticence of his idealization of Matter-tangible as well as visible. Cf.
_Principles_, sect. 44.
326 This connexion of our knowledge of distance with our locomotive experience points to a theory which ultimately resolves s.p.a.ce into experience of unimpeded locomotion.
327 Locke (_Essay_, Introduction, -- 8) takes _idea_ vaguely as "the term which serves best to stand whatsoever is the object of the understanding when a man thinks." Oversight of what Berkeley intends the term idea has made his whole conception of nature and the material universe a riddle to many, of which afterwards.
328 The expressive term "outness," favoured by Berkeley, is here first used.
329 "We get the idea of s.p.a.ce," says Locke, "both by our sight and touch" (_Essay_, II. 13. -- 2). Locke did not contemplate Berkeley"s ant.i.thesis of visible and tangible extension, and the consequent ambiguity of the term extension; which sometimes signifies _coloured_, and at others _resistant_ experience in sense.
330 For an explanation of this difficulty, see sect. 144.
331 "object"-"thing," in the earlier editions.
332 This is the issue of the a.n.a.lytical portion of the _Essay_.
333 Cf. sect. 139-40.
334 Here the question of externality, signifying independence of all percipient life, is again mixed up with that of the invisibility of distance outwards in the line of sight.
335 Omitted in author"s last edition.
336 i.e. including muscular and locomotive experience as well as sense of contact. But what are the _tangibilia_ themselves? Are they also significant, like _visibilia_, of a still ulterior reality? This is the problem of the _Principles of Human Knowledge_.
337 In this section the conception of a natural Visual Language, makes its appearance, with its implication that Nature is (for us) virtually Spirit. Cf. sect. 140, 147-_Principles_, sect.
44-_Dialogues of Hylas and Philonous_-_Alciphron_, IV. 8, 11-and _Theory of Vision Vindicated_, pa.s.sim.
338 Sect. 52-87 treat of the invisibility of real, i.e. tactual, Magnitude. Cf. _Theory of Vision Vindicated_, sect. 54-61.
339 Sect. 8-15.
340 Sect. 41, &c.
341 See Molyneux"s _Treatise on Dioptrics_, B. I. prop. 28.
342 See sect. 122-126.
343 In short there is a point at which, with our limited sense, we cease to be percipient of colour, in seeing; and of resistance, in locomotion. Though Berkeley regards all visible extensions as sensible, and therefore dependent for their reality on being realised by sentient mind, he does not mean that mind or consciousness is extended. With him, extension, though it exists only in mind,-i.e. as an idea seen, in the case of visible extension, and as an idea touched, in the case of tangible extension,-is yet no _property_ of mind. Mind can exist without being percipient of extension, although extension cannot be realised without mind.
344 But this is true, though less obviously, of tangible as well as of visible objects.
345 Sect. 49.
346 Cf. sect. 139, 140, &c.
347 "situation"-not in the earlier editions.
348 Sect. 55.
349 Omitted in the author"s last edition.
350 Ordinary sight is virtually foresight. Cf. sect. 85.-See also Malebranche on the external senses, as given primarily for the urgent needs of embodied life, not to immediately convey scientific knowledge, _Recherche_, Liv. I. ch. 5, 6, 9, &c.
351 Sect. 44.-See also sect. 55, and note.
352 This supposes "settled" _tangibilia_, but not "settled" _visibilia_.
Yet the sensible extension given in touch and locomotive experience is also relative-an object being _felt_ as larger or smaller according to the state of the organism, and the other conditions of our embodied perception.
353 What follows, to end of sect. 63, added in the author"s last edition.
354 "outward objects," i.e. objects of which we are percipient in tactual experience, taken in this _Essay_ provisionally as the real external objects. See _Principles_, sect. 44.
355 Cf. sect. 144. Note, in this and the three preceding sections, the stress laid on the _arbitrariness_ of the connexion between the signs which suggest magnitudes, or other modes of extension, and their significates. This is the foundation of the _New Theory_; which thus resolves _physical_ causality into a relation of signs to what they signify and predict-a.n.a.logous to the relation between words and their accepted meanings.
356 In sect. 67-78, Berkeley attempts to verify the foregoing account of the natural signs of Size, by applying it to solve a phenomenon, the cause of which had been long debated among men of science-the visible magnitude of heavenly bodies when seen in the horizon.
357 Cf. sect. 10.
358 Omitted in the author"s last edition. Cf sect. 76, 77.-The explanation in question is attributed to Alhazen, and by Bacon to Ptolemy, while it is sanctioned by eminent scientific names before and since Berkeley.
359 "Fourthly" in the second edition. Cf. what follows with sect. 74.
Why "lesser"?
360 When Berkeley, some years afterwards, visited Italy, he remarked that distant objects appeared to him much nearer than they really were-a phenomenon which he attributed to the comparative purity of the southern air.
361 i.e. the original perception, apart from any synthetic operation of suggestion and inferential thought, founded on visual signs.
362 In Riccioli"s _Almagest_, II. lib. X. sect. 6. quest. 14, we have an account of many hypotheses then current, in explanation of the apparent magnitude of the horizontal moon.
363 Ga.s.sendi"s "Epistolae quatuor de apparente magnitudine solis humilis et sublimis."-_Opera_, tom. III pp. 420-477. Cf. Appendix to this _Essay_, p. 110.
364 See _Dioptrique_, VI.
_ 365 Opera Latina_, vol. I, p. 376, vol. II, pp. 26-62; _English Works_, vol. I. p. 462. (Molesworth"s Edition.)
366 The paper in the Transactions is by Molyneux.
367 See Smith"s _Optics_, pp. 64-67, and _Remarks_, pp. 48, &c. At p. 55 Berkeley"s _New Theory_ is referred to, and p.r.o.nounced to be at variance with experience. Smith concludes by saying, that in "the second edition of Berkeley"s _Essay_, and also in a Vindication and Explanation of it (called the _Visual Language_), very lately published, the author has made some additions to his solution of the said phenomenon; but seeing it still involves and depends on the principle of faintness, I may leave the rest of it to the reader"s consideration." This, which appeared in 1738, is one of the very few early references to Berkeley"s _New Theory of Vision Vindicated_.
368 Sect. 2-51.
369 This sentence is omitted in the author"s last edition.