I publish not this so much for anything else as to know whether other men have the same ideas as we Irishmen. This is my end, & not to be inform"d as to my own particular.
My speculations have the same effect as visiting foreign countries: in the end I return where I was before, but my heart at ease, and enjoying life with new satisfaction.
Pa.s.sing through all the sciences, though false for the most part, yet it gives us the better insight and greater knowledge of the truth.
He that would bring another over to his opinion, must seem to harmonize with him at first, and humour him in his own way of talking(274).
From my childhood I had an unaccountable turn of thought that way.
It doth not argue a dwarf to have greater strength than a giant, because he can throw off the molehill which is upon him, while the other struggles beneath a mountain.
The whole directed to practise and morality-as appears 1st, from making manifest the nearness and omnipresence of G.o.d; 2dly, from cutting off the useless labour of sciences, and so forth.
AN ESSAY TOWARDS A NEW THEORY OF VISION
_First published in 1709_
Editor"s Preface To The Essay Towards A New Theory Of Vision
Berkeley"s _Essay towards a New Theory of Vision_ was meant to prepare the way for the exposition and defence of the new theory of the material world, its natural order, and its relation to Spirit, that is contained in his book of _Principles_ and in the relative _Dialogues_, which speedily followed. The _Essay_ was the firstfruits of his early philosophical studies at Dublin. It was also the first attempt to show that our apparently immediate Vision of s.p.a.ce and of bodies extended in three-dimensioned s.p.a.ce, is either tacit or conscious inference, occasioned by constant a.s.sociation of the phenomena of which alone we are visually percipient with a.s.sumed realities of our tactual and locomotive experience.
The first edition of the _Essay_ appeared early in 1709, when its author was about twenty-four years of age. A second edition, with a few verbal changes and an Appendix, followed before the end of that year. Both were issued in Dublin, "printed by Aaron Rhames, at the back of d.i.c.k"s Coffeehouse, for Jeremy Pepyat, bookseller in Skinner Row." In March, 1732, a third edition, without the Appendix, was annexed to _Alciphron,_ on account of its relation to the Fourth Dialogue in that book. This was the author"s last revision.
In the present edition the text of this last edition is adopted, after collation with those preceding. The Appendix has been restored, and also the Dedication to Sir John Percival, which appeared only in the first edition.
A due appreciation of Berkeley"s theory of seeing, and his conception of the visible world, involves a study, not merely of this tentative juvenile _Essay_, but also of its fuller development and application in his more matured works. This has been commonly forgotten by his critics.
Various circ.u.mstances contribute to perplex and even repel the reader of the _Essay_, making it less fit to be an easy avenue of approach to Berkeley"s _Principles_.
Its occasion and design, and its connexion with his spiritual conception of the material world, are suggested in Sections 43 and 44 of the _Principles_. Those sections are a key to the _Essay_. They inform us that in the _Essay_ the author intentionally uses language which seems to attribute a reality independent of all percipient spirit to the ideas or phenomena presented in Touch; it being beside his purpose, he says, to "examine and refute" that "vulgar error" in "a work on Vision." This studied reticence of a verbally paradoxical conception of Matter, in reasonings about vision which are fully intelligible only under that conception, is one cause of a want of philosophical lucidity in the _Essay_.
Another circ.u.mstance adds to the embarra.s.sment of those who approach the _Principles_ and the three _Dialogues_ through the _Essay on Vision_. The _Essay_ offers no exception to the lax employment of equivocal words familiar in the early literature of English philosophy, but which is particularly inconvenient in the subtle discussions to which we are here introduced. At the present day we are perhaps accustomed to more precision and uniformity in the philosophical use of language; at any rate we connect other meanings than those here intended with some of the leading words. It is enough to refer to such terms as _idea_, _notion_, _sensation_, _perception_, _touch_, _externality_, _distance_, and their conjugates. It is difficult for the modern reader to revive and remember the meanings which Berkeley intends by _idea_ and _notion_-so significant in his vocabulary; and _touch_ with him connotes muscular and locomotive experience as well as the pure sense of contact. Interchange of the terms _outward_, _outness_, _externality_, _without the mind_, and _without the eye_ is confusing, if we forget that Berkeley implies that percipient mind is virtually coextensive with our bodily organism, so that being "without"
or "at a distance from" our bodies is being at a distance from the percipient mind. I have tried in the annotations to relieve some of these ambiguities, of which Berkeley himself warns us (cf. sect. 120).
The _Essay_ moreover abounds in repet.i.tions, and interpolations of antiquated optics and physiology, so that its logical structure and even its supreme generalisation are not easily apprehended. I will try to disentangle them.
The reader must remember that this _Essay on Vision_ is professedly an introspective appeal to human consciousness. It is an a.n.a.lysis of what human beings are conscious of when they see, the results being here and there applied, partly by way of verification, to solve some famous optical or physiological puzzle. The aim is to present the facts, the whole facts, and nothing but the facts of our internal visual experience, as distinguished from supposed facts and empty abstractions, which an irregular exercise of imagination, or abuse of words, had put in their place. The investigation, moreover, is not concerned with s.p.a.ce in its metaphysical infinity, but with finite sections of s.p.a.ce and their relations, which concern the sciences, physical and mathematical, and with real or tangible Distance, Magnitude, and Place, in their relation to seeing.
From the second section onwards the _Essay_ naturally falls into six Parts, devoted successively to the proof of the six following theses regarding the relation of Sight to finite s.p.a.ces and to things extended:-
I. (Sect. 2-51.) Distance, or outness from the eye in the line of vision, is not seen: it is only suggested to the mind by visible phenomena and by sensations felt in the eye, all which are somehow its arbitrarily const.i.tuted and non-resembling Signs.
II. (Sect. 52-87.) Magnitude, or the amount of s.p.a.ce that objects of sense occupy, is really invisible: we only see a greater or less quant.i.ty of colour, and colour depends upon percipient mind: our supposed visual perceptions of real magnitude are only our own interpretations of the tactual meaning of the colours we see, and of sensations felt in the eye, which are its Signs.
III. (Sect. 88-120.) Situation of objects of sense, or their real relation to one another in ambient s.p.a.ce, is invisible: what we see is variety in the relations of colours to one another: our supposed vision of real tangible locality is only our interpretation of its visual non-resembling Signs.
IV. (Sect. 121-46.) There is no object that is presented in common to Sight and Touch: s.p.a.ce or extension, which has the best claim to be their common object, is specifically as well as numerically different in Sight and in Touch.
V. (Sect. 147-48.) The explanation of the tactual significance of the visible and visual Signs, upon which human experience proceeds, is offered in the Theory that all visible phenomena are arbitrary signs in what is virtually the Language of Nature, addressed by G.o.d to the senses and intelligence of Man.
VI. (Sect. 149-60.) The true object studied in Geometry is the kind of Extension given in Touch, not that given in Sight: real Extension in all its phases is tangible, not visible: colour is the only immediate object of Sight, and colour being mind-dependent sensation, cannot be realised without percipient mind. These concluding sections are supplementary to the main argument.
The fact that distance or outness is invisible is sometimes regarded as Berkeley"s contribution to the theory of seeing. It is rather the a.s.sumption on which the _Essay_ proceeds (sect. 2). The _Essay_ does not prove this invisibility, but seeks to shew how, notwithstanding, we learn to find outness through seeing. That the relation between the visual signs of outness, on the one hand, and the real distance which they signify, on the other, is in all cases arbitrary, and discovered through experience, is the burden of sect. 2-40. The previously recognised signs of "considerably remote" distances, are mentioned (sect. 3). But _near_ distance was supposed to be inferred by a visual geometry-and to be "suggested," not signified by arbitrary signs. The determination of the visual signs which suggest outness, near and remote, is Berkeley"s professed discovery regarding vision.
An induction of the visual signs which "suggest" distance, is followed (sect. 43) by an a.s.sertion of the wholly sensuous reality of _colour_, which is acknowledged to be the only immediate object of sight. Hence _visible_ extension, consisting in colour, must be dependent for its realisation upon sentient or percipient mind. It is then argued (sect. 44) that this mind-dependent visible outness has no resemblance to the tangible reality (sect. 45). This is the first pa.s.sage in the _Essay_ in which Touch and its data are formally brought into view. Tactual or locomotive experience, it is implied, is needed to infuse true reality into our conceptions of distance or outness. This cannot be got from seeing any more than from hearing, or tasting, or smelling. It is as impossible to see and touch the same object as it is to hear and touch the same object. Visible objects and ocular sensations can only be _ideal signs_ of _real things_.
The sections in which Touch is thus introduced are among the most important in the _Essay_. They represent the outness given in hearing as wholly sensuous, ideal, or mind-dependent: they recognise as more truly real that got by contact and locomotion. But if this is all that man can see, it follows that his _visible_ world, at any rate, becomes real only in and through percipient mind. The problem of an _Essay on Vision_ is thus, to explain _how_ the visible world of extended colour can inform us of tangible realities, which it does not in the least resemble, and with which it has no _necessary_ connexion. That visible phenomena, or else certain organic sensations involved in seeing (sect. 3, 16, 21, 27), gradually _suggest_ the real or tangible outness with which they are connected in the divinely const.i.tuted system of nature, is the explanation which now begins to dawn upon us.
Here an ambiguity in the _Essay_ appears. It concludes that the _visible_ world cannot be real without percipient realising mind, i.e. not otherwise than ideally: yet the argument seems to take for granted that we are percipient of a _tangible_ world that is independent of percipient realising mind. The reader is apt to say that the tangible world must be as dependent on percipient mind for its reality as the visible world is concluded to be, and for the same reason. This difficulty was soon afterwards encountered in the book of _Principles_, where the worlds of sight and touch are put on the same level; and the possibility of unperceived reality in both cases is denied; on the ground that a material world cannot be realised in the total absence of Spirit-human and divine.
The term "external" may still be applied to tactual and locomotive phenomena alone, if men choose; but this not because of the ideal character of what is seen, and the unideal reality of what is touched, but only because tactual perceptions are found to be more firm and steady than visual. Berkeley preferred in this way to _insinuate_ his new conception of the material world by degrees, at the risk of exposing this juvenile and tentative _Essay on Vision_ to a charge of incoherence.
The way in which visual ideas or phenomena "suggest" the outness or distance of things from the organ of sight having been thus explained, in what I call the First Part of the _Essay_, the Second and Third Parts (sect. 52-120) argue for the invisibility of real extension in two other relations, viz. magnitude and locality or situation. An induction of the visual signs of tangible size and situation is given in those sections.
The result is applied to solve two problems then notable in optics, viz.
(1) the reason for the greater visible size of the horizontal moon than of the moon in its meridian (sect. 67-87); and (2) the fact that objects are placed erect in vision only on condition that their images on the retina are inverted (sect. 88-120). Here the ant.i.thesis between the ideal world of coloured extension, and the real world of resistant extension is pressed with vigour. The "high" and "low" of the visible world is not the "high" and "low" of the tangible world (sect. 91-106). There is no resemblance and no necessary relation, between those two so-called extensions; not even when the number of visible objects happen to coincide with the number of tangible objects of which they are the visual signs, e.g. the visible and tangible fingers on the hand: for the born-blind, on first receiving sight, could not parcel out the visible phenomena in correspondence with the tangible.
The next Part of the _Essay_ (sect. 121-45) argues for a specific as well as a numerical difference between the original data of sight and the data of touch and locomotion. Sight and touch perceive nothing in common.
Extension in its various relations differs in sight from extension in touch. Coloured extension, which alone is visible, is found to be different in kind from resistant extension, which alone is tangible. And if actually perceived or concrete extensions differ thus, the question is determined. For all extension with which man can be concerned must be concrete (sect. 23). Extension in the abstract is meaningless (sect.
124-25). What remains is to marshal the scattered evidence, and to guard the foregoing conclusions against objections. This is attempted in sections 128-46.
The enunciation of the summary generalisation, which forms the "New Theory of Vision" (sect. 147-8), may be taken as the Fifth and culminating Part of the _Essay_.