My design is to shew the manner wherein we perceive by sight the distance, magnitude, and situation of objects. Also to consider the difference there is betwixt the ideas of sight and touch, and whether there be any idea common to both senses.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
It is, I think, agreed by all that distance, of itself and immediately, cannot be seen. For distance being a Line directed end-wise to the eye, it projects only one point in the fund of the eye, which point remains invariably the same, whether the distance be longer or shorter.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication1709). 1732.
Betwixt which and the foregoing manner of estimating distance there is this remarkable difference: that whereas there was no apparent, necessary connexion between small distance and a large and strong appearance, or between great distance and a little and faint appearance, there appears a very necessary connexion between an obtuse angle and near distance, and an acute angle and farther distance. It does not in the least depend upon experience, but may be evidently known by anyone before he had experienced it, that the nearer the concurrence of the optic axes, the greater the angle, and the remoter their concurrence is, the lesser will be the angle comprehended by them.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
In this case also it is plain we are not beholding to experience: it being a certain, necessary truth that the nearer the direct rays falling on the eye approach to a parallelism, the farther off is the point of their intersection, or the visible point from whence they flow.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Now from sect. 2 it is plain that distance is in its own nature imperceptible, and yet it is perceived by sight. It remains, therefore, that it be brought into view by means of some other idea that is itself immediately perceived in the act of vision.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Since, therefore, those angles and lines are not themselves perceived by sight, it follows from sect. 10 that the mind doth not by them judge of the distance of objects.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
The last reason I shall give for rejecting that doctrine is, that though we should grant the real existence of those optic angles, etc., and that it was possible for the mind to perceive them, yet these principles would not be found sufficient to explain the phenomena of distance, as shall be shewn hereafter.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication1709). 1732.
26. Thus, greater confusion having been constantly attended with nearer distance, no sooner is the former idea perceived, but it suggests the latter to our thoughts. And if it had been the ordinary course of Nature that the farther off an object were placed, the more confused it should appear, it is certain the very same perception that now makes us think an object approaches would then have made us to imagine it went farther off. That perception, abstracting from custom and experience, being equally fitted to produce the idea of great distance, or small distance, or no distance at all.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
The ancient and received principle, which Dr. Barrow here mentions as the main foundation of Tacquet's Catoptrics, is that: every visible point seen by reflexion from a speculum shall appear placed at the intersection of the reflected ray, and the perpendicular of incidence. Which intersection in the present case, happening to be behind the eye, it greatly shakes the authority of that principle, whereon the aforementioned author proceeds throughout his whole Catoptrics in determining the apparent place of objects seen by reflexion from any kind of speculum.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
This case is much the same as if we should suppose an Englishman to meet a foreigner who used the same words with the English, but in a direct contrary signification. The Englishman would not fail to make a wrong judgment of the ideas annexed to those sounds in the mind of him that used them. Just so, in the present case the object speaks (if I may so say) with words that the eye is well acquainted with, that is, confusions of appearance; but whereas heretofore the greater confusions were always wont to signify nearer distances, they have in this case a direct, contrary signification, being connected with the greater distances. Whence it follows that the eye must unavoidably be mistaken, since it will take the confusions in the sense it has been used to, which is directly opposed to the true.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
It hath been shewn there are two sorts of objects apprehended by sight; each whereof hath its distinct magnitude, or extension. The one, properly tangible, i.e. to be perceived and measured by touch, and not immediately falling under the sense of seeing: the other, properly and immediately visible, by mediation of which the former is brought in view. Each of these magnitudes are greater or lesser, according as they contain in them more or fewer points, they being made up of points or minimums. For, whatever may be said of extension in abtract, it is certain sensible extension is not infinitely divisible. There is a Minimum Tangibile and a Minimum Visibile, beyond which sense cannot perceive. This everyone's experience will inform him.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
That the matter of fact is true will be evident to anyone who considers that a man placed at ten foot distance is thought as great as if he were placed at a distance only of five foot: which is true not with relation to the visible, but tangible greatness of the object: the visible magnitude being far greater at one station: than it is at the other.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
As we see distance, so we see magnitude. And we see both in the same way that we see shame or anger in the looks of a man. Those passions are themselves invisible, they are nevertheless let in by the eye along with colours and alterations of countenance, which are the immediate object of vision: and which signify them for no other reason than barely because they have been observed to accompany them. Without which experience we should no more have taken blushing for a sign of shame than of gladness.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Farther, the air being variously impregnated, sometimes more and sometimes less, with vapours and exhalations fitted to retund and intercept the rays of light, it follows that the appearance of the horizontal moon hath not always an equal faintness, and by consequence that luminary, though in the very same situation, is at one time judged greater than at another.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Many attempts have been made by learned men to account for this appearance. Gassendus, Descartes, Hobbes, and several others have employed their thoughts on that subject; but how fruitless and unsatisfactory their endeavours have been is sufficiently shewn in The Philosophical Transactions, where you may see their several opinions at large set forth and confuted, not without some surprize at the gross blunders that ingenious men have been forced into by endeavouring to reconcile this appearance with the ordinary Principles of optics. Since the writing of which there hath been published in the Transactions[5] another paper relating to the same affair by the celebrated Dr. Wallis, wherein he attempts to account for that phenomenon which, though it seems not to contain anything new or different from what had been said before by others, I shall nevertheless consider in this place.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
For the better explaining the nature of vision, and setting the manner wherein we perceive magnitudes in a due light, I shall proceed to make some observations concerning matters relating thereto, whereof the want of reflexion, and duly separating between tangible and visible ideas, is apt to create in us mistaken and confused notions.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
And first, I shall observe· that the minimum visibile is exactly equal in all beings whatsoever that are endowed with the visive faculty. No exquisite formation of the eye, no peculiar sharpness of sight, can make it less in one creature than in another; for it not being distinguishable into parts, nor in any wise a consisting of them, it must necessarily be the same to all. For suppose it otherwise, and that the minimum visibile of a mite, for instance, be less than the minimum visibile of a man: the latter therefore may by detraction of some part be made equal to the former: it doth therefore consist of parts, which is inconsistent with the notion of a minimum visibile or point.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Corresponding to these two defects of sight, we may imagine as many perfections, to wit, 1st, that of comprehending in one view a greater number of visible points. 2dly, of being able to view them all equally and at once with the utmost clearness and distinction. That those perfections are not actually in some intelligences of a different order and capacity from ours it is impossible for us to know.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Upon the whole it seems that if we consider the use and end of sight, together with the present state and circumstances of our being, we shall not find any great cause to complain of any defect or imperfection in it, or easily conceive how it could be mended. With such admirable wisdom is that faculty contrived, both for the pleasure and convenience of life.
George Berkeley An Essay towards a new theory of Vision. 1732, first edition published 1709
It remains, therefore, that we look for some other explication of this difficulty: and I believe it not impossible to find one, provided we examine it to the bottom, and carefully distinguish between the ideas of sight and touch; which cannot be too oft inculcated in treating of vision: but more especially throughout the consideration of this affair we ought to carry that distinction in our thoughts: for that from want of a right understanding thereof the difficulty of explaining erect vision seems chiefly to arise.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Afterwards, when upon turning his head or eyes up and down to the right and left he shall observe the visible objects to change, and shall also attain to know that they are called by the same names, and connected with the objects perceived by touch; then indeed he will come to speak of them and their situation, in the same terms that he has been used to apply to tangible things; and those that he perceives by turning up his eyes he will call upper, and those that by turning down his eyes he will call lower.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Farther, when he has by experience learned the connexion there is between the several ideas of sight and touch, he will be able, by the perception he has of the situation of visible things in respect of one another, to make a sudden and true estimate of the situation of outward, tangible things corresponding to them. And thus it is he shall perceive by sight the situation of external objects which do not properly fall under that sense.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Rightly to conceive this point we must carefully distinguish between the ideas of sight and touch, between the visible and tangible eye; for certainly on the tangible eye nothing either is or seems to be painted. Again, the visible eye, as well as all other visible objects, hath been shewn to exist only in the mind, which perceiving its own ideas, and comparing them together, calls some pictures in respect of others. What hath been said, being rightly comprehended and laid together, doth, I think, afford a full and genuine explication of the erect appearance of objects; which phenomenon, I must confess, I do not see how it can be explained by any theories of vision hitherto made public.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
Some, perhaps, may think pure space,vacuum, or trine dimension to be equally the object of sight and touch: but though we have a very great propension to think the ideas of outness and space to be the immediate object of sight, yet, if I mistake not, in the foregoing parts of this essay that hath been clearly demonstated to be a mere delusion, arising from the quick and sudden suggestion of fancy, which so closely connects the idea of distance with those of sight, that we are apt to think it is itself a proper and immediate object of that sense till reason corrects the mistake.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
The prejudice which is grounded on these, and whatever other causes may be assigned thereof, sticks so fast that it is impossible without obstinate striving and labour of the mind to get entirely clear of it. But then the reluctancy we find in rejecting any opinion can be no argument of its truth to whoever considers what has been already shewn with regard to the prejudices we entertain concerning the distance, magnitude, and situation of objects; prejudices so familiar to our minds, so confirmed and inveterate, as they will hardly give way to the clearest demonstration.
Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
I do not design to trouble myself with drawing corollaries from the doctrine I have hitherto laid down. If it bears the test others may, so far as they shall think convenient, employ their thoughts in extending it farther, and applying it to whatever purposes it may be subservient to: only, I cannot forbear making some inquiry concerning the object of geometry, which the subject we have been upon doth naturally lead one to. We have shewn there is no such idea as that of extension in abstract, and that there are two kinds of sensible extension and figures which are entirely distinct and heterogeneous from each other. Now, it is natural to inquire which of these is the object of geometry. Berkeley, George. An Essay Towards a New Theory of Vision. (Original Publication, 1709). 1732.
You will perhaps wonder that an obscure person, who has not the honour to be known to your lordship, should presume to address you in this manner. But that a man who has written something with a design to promote Useful Knowledge and Religion in the world should make choice of your lordship for his patron, will not be thought strange by any one that is not altogether unacquainted with the present state of the church and learning, and consequently ignorant how great an ornament and support you are to both. Yet, nothing could have induced me to make you this present of my poor endeavours, were I not encouraged by that candour and native goodness which is so bright a part in your lordship's character.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
I might add, my lord, that the extraordinary favour and bounty you have been pleased to show towards our Society gave me hopes you would not be unwilling to countenance the studies of one of its members. These considerations determined me to lay this treatise at your lordship's feet, and the rather because I was ambitious to have it known that I am with the truest and most profound respect, on account of that learning and virtue which the world so justly admires in your lordship.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
Philosophy being nothing else but the study of wisdom and truth, it may with reason be expected that those who have spent most time and pains in it should enjoy a greater calm and serenity of mind, a greater clearness and evidence of knowledge, and be less disturbed with doubts and difficulties than other men.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
Yet so it is, we see the illiterate bulk of mankind that walk the high-road of plain common sense, and are governed by the dictates of nature, for the most part easy and undisturbed. To them nothing that is familiar appears unaccountable or difficult to comprehend. They complain not of any want of evidence in their senses, and are out of all danger of becoming Sceptics.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
But no sooner do we depart from sense and instinct to follow the light of a superior principle, to reason, meditate, and reflect on the nature of things, but a thousand scruples spring up in our minds concerning those things which before we seemed fully to comprehend. Prejudices and errors of sense do from all parts discover themselves to our view; and, endeavouring to correct these by reason, we are insensibly drawn into uncouth paradoxes, difficulties, and inconsistencies, which multiply and grow upon us as we advance in speculation, till at length, having wandered through many intricate mazes, we find ourselves just where we were, or, which is worse, sit down in a forlorn Scepticism.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
The cause of this is thought to be the obscurity of things, or the natural weakness and imperfection of our understandings. It is said, the faculties we have are few, and those designed by nature for the support and comfort of life, and not to penetrate into the inward essence and constitution of things. Besides, the mind of man being finite, when it treats of things which partake of infinity, it is not to be wondered at if it run into absurdities and contradictions, out of which it is impossible it should ever extricate itself, it being of the nature of infinite not to be comprehended by that which is finite.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
My purpose therefore is, to try if I can discover what those Principles are which have introduced all that doubtfulness and uncertainty, those absurdities and contradictions, into the several sects of philosophy; insomuch that the wisest men have thought our ignorance incurable, conceiving it to arise from the natural dulness and limitation of our faculties. And surely it is a work well deserving our pains to make a strict inquiry concerning the First Principles of Human Knowledge, to sift and examine them on all sides, especially since there may be some grounds to suspect that those lets and difficulties, which stay and embarrass the mind in its search after truth, do not spring from any darkness and intricacy in the objects, or natural defect in the understanding, so much as from false Principles which have been insisted on, and might have been avoided.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
It is agreed on all hands that the qualities or modes of things do never really exist each of them apart by itself, and separated from all others, but are mixed, as it were, and blended together, several in the same object. But, we are told, the mind being able to consider each quality singly, or abstracted from those other qualities with which it is united, does by that means frame to itself abstract ideas. For example, there is perceived by sight an object extended, coloured, and moved: this mixed or compound idea the mind resolving into its simple, constituent parts, and viewing each by itself, exclusive of the rest, does frame the abstract ideas of extension, colour, and motion. Not that it is possible for colour or motion to exist without extension; but only that the mind can frame to itself by abstraction the idea of colour exclusive of extension, and of motion exclusive of both colour and extension.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
10. Whether others have this wonderful faculty of abstractingtheir ideas, they best can tell: for myself, I find indeed I have a faculty of imagining, or representing to myself, the ideas of those particular things I have perceived, and of variously compounding and dividing them. I can imagine a man with two heads, or the upper parts of a man joined to the body of a horse. I can consider the hand, the eye, the nose, each by itself abstracted or separated from the rest of the body. But then whatever hand or eye I imagine, it must have some particular shape and colour.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
Likewise the idea of man that I frame to myself must be either of a white, or a black, or a tawny, a straight, or a crooked, a tall, or a low, or a middle-sized man. I cannot by any effort of thought conceive the abstract idea above described. And it is equally impossible for me to form the abstract idea of motion distinct from the body moving, and which is neither swift nor slow, curvilinear nor rectilinear; and the like may be said of all other abstract general ideas whatsoever. To be plain, I own myself able to abstract in one sense, as when I consider some particular parts or qualities separated from others, with which, though they are united in some object, yet it is possible they may really exist without them.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
But I deny that I can abstract from one another, or conceive separately, those qualities which it is impossible should exist so separated; or that I can frame a general notion, by abstracting from particulars in the manner aforesaid- which last are the two proper acceptations of abstraction. And there are grounds to think most men will acknowledge themselves to be in my case. The generality of men which are simple and illiterate never pretend to abstract notions. It is said they are difficult and not to be attained without pains and study; we may therefore reasonably conclude that, if such there be, they are confined only to the learned.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
Much is here said of the difficulty that abstract ideas carry with them, and the pains and skill requisite to the forming them. And it is on all hands agreed that there is need of great toil and labour of the mind, to emancipate our thoughts from particular objects, and raise them to those sublime speculations that are conversant about abstract ideas.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
We have, I think, shewn the impossibility of Abstract Ideas. We have considered what has been said for them by their ablest patrons; and endeavored to show they are of no use for those ends to which they are thought necessary. And lastly, we have traced them to the source from whence they flow, which appears evidently to be language.- It cannot be denied that words are of excellent use, in that by their means all that stock of knowledge which has been purchased by the joint labours of inquisitive men in all ages and nations may be drawn into the view and made the possession of one single person.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
But at the same time it must be owned that most parts of knowledge have been strangely perplexed and darkened by the abuse of words, and general ways of speech wherein they are delivered. Since therefore words are so apt to impose on the understanding, whatever ideas I consider, I shall endeavour to take them bare and naked into my view, keeping out of my thoughts so far as I am able, those names which long and constant use hath so strictly united with them; from which I may expect to derive the following advantages: [...]
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
But, these being known to be mistakes, a man may with greater ease prevent his being imposed on by words. He that knows he has no other than particular ideas, will not puzzle himself in vain to find out and conceive the abstract idea annexed to any name. And he that knows names do not always stand for ideas will spare himself the labour of looking for ideas where there are none to be had. It were, therefore, to be wished that everyone would use his utmost endeavours to obtain a clear view of the ideas he would consider, separating from them all that dress and incumbrance of words which so much contribute to blind the judgment and divide the attention.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
In vain do we extend our view into the heavens and pry into the entrails of the earth, in vain do we consult the writings of learned men and trace the dark footsteps of antiquity- we need only draw the curtain of words, to hold the fairest tree of knowledge, whose fruit is excellent, and within the reach of our hand.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge, Preface. (Original Publication, 1709). 1710.
All our ideas, sensations, notions, or the things which we perceive, by whatsoever names they may be distinguished, are visibly inactive- there is nothing of power or agency included in them. So that one idea or object of thought cannot produce or make any alteration in another.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge. (Original Publication, 1709). 1710.
To be satisfied of the truth of this, there is nothing else requisite but a bare observation of our ideas. For, since they and every part of them exist only in the mind, it follows that there is nothing in them but what is perceived: but whoever shall attend to his ideas, whether of sense or reflexion, will not perceive in them any power or activity; there is, therefore, no such thing contained in them. A little attention will discover to us that the very being of an idea implies passiveness and inertness in it, insomuch that it is impossible for an idea to do anything, or, strictly speaking, to be the cause of anything: neither can it be the resemblance or pattern of any active being, as is evident from sect. 8. Whence it plainly follows that extension, figure, and motion cannot be the cause of our sensations. To say, therefore, that these are the effects of powers resulting from the configuration, number, motion, and size of corpuscles, must certainly be false.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge. (Original Publication, 1709). 1710.
That neither our thoughts, nor passions, nor ideas formed by the imagination, exist without the mind, is what everybody will allow. And it seems no less evident that the various sensations or ideas imprinted on the sense, however blended or combined together (that is, whatever objects they compose), cannot exist otherwise than in a mind perceiving them.- I think an intuitive knowledge may be obtained of this by any one that shall attend to what is meant by the term exists, when applied to sensible things. The table I write on I say exists, that is, I see and feel it; and if I were out of my study I should say it existed- meaning thereby that if I was in my study I might perceive it, or that some other spirit actually does perceive it. There was an odour, that is, it was smelt; there was a sound, that is, it was heard; a colour or figure, and it was perceived by sight or touch. This is all that I can understand by these and the like expressions. For as to what is said of the absolute existence of unthinking things without any relation to their being perceived, that seems perfectly unintelligible. Their esse is percepi, nor is it possible they should have any existence out of the minds or thinking things which perceive them.
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge. (Original Publication, 1709). 1710.
It is indeed an opinion strangely prevailing amongst men, that houses, mountains, rivers, and in a word all sensible objects, have an existence, natural or real, distinct from their being perceived by the understanding. But, with how great an assurance and acquiescence soever this principle may be entertained in the world, yet whoever shall find in his heart to call it in question may, if I mistake not, perceive it to involve a manifest contradiction. For, what are the fore-mentioned objects but the things we perceive by sense? and what do we perceive besides our own ideas or sensations? and is it not plainly repugnant that any one of these, or any combination of them, should exist unperceived?
Berkeley, George. A Treatise Concerning the Principles of Human Knowledge. (Original Publication, 1709). 1710.
