exhaustible fund of entertainment, in Berkeley's own short but masterly exposition of his principles, and in the excellent comments upon it by Smith of Cambridge; by Porterfield; by Reid; and, still more lately, by the author of the Wealth of Nations.*

That this doctrine, with respect to the acquired perceptions of sight, was quite unknown to the best metaphysicians of antiquity, we have direct evidence in a passage of Aristotle's Nicomachean Ethics, where he states the distinction between those endowments which are the immediate gift of nature, and those which are the fruit of custom and habit. In the former class, he ranks the perceptions of sense, mentioning particularly the senses of seeing and of hearing. The passage (which I have transcribed in a Note) is curious, and seems to me decisive on the subject.+

The misapprehensions of the ancients on this very obscure question will not appear surprising, when it is considered, that forty years after the publication of Berkeley's Theory of Vision, and sixty years after the date of Locke's Essay, the subject was so imperfectly understood in France, that Condillac (who is, to this day, very generally regarded by his countrymen as the father of genuine logic and metaphysics,) combated at great length the conclusions of the English philosophers, concerning the acquired perceptions of sight; affirming, that "the eye judges naturally of figures, of magnitudes, of situations, and of distances." His argument in support of this opinion is to be found in the sixth section of his Essay on the Origin of Human Knowledge.

It is difficult to suppose that a person of mature years, who had read and studied Locke and Berkeley with as

By this excellent judge, Berkeley's New Theory of Vision is pronounced to be "one of the finest examples of Philosophical Analysis that is to be found in our own, or any other language." (Essays on Philosophical Subjects. Lond. 1795, p. 215.) † Οὐ γὰρ ἐκ τοῦ πολλάκις ἰδεῖν ἢ πολλάκις ἀκοῦσαι, τὰς αἰσθήσεις ἐλάβομεν, ἀλλ' ἀνά παλιν, ἔχοντες ἐχρησάμεθα, οὐ χρησάμενοι ἔχομεν. (Ethic. Nicomach. Lib. ii. cap. 1.) "For it is not from seeing often, or from hearing often, that we get these senses; but, on the contrary, instead of getting them by using them, we use them because we have got them."

Had Aristotle been at all aware of the distinction so finely illustrated by Berkeley, instead of appealing to the perceptions of these two senses, as instances of endowments coeval with our birth, he would have quoted them as the most striking of all examples of the effects of custom in apparently identifying our acquired powers with our original faculties.

much care and attention as Condillac appears to have bestowed on them, should have reverted to this ancient and vulgar prejudice; without suspecting that his metaphysical depth has been somewhat overrated by the world.* It is but justice, however, to Condillac, to add, that, in a subsequent work, he had the candor to acknowledge and to retract his error; a rare example of that disinterested love of truth, which is so becoming in a philosopher. I quote the passage (in a literal, though somewhat abridged version,) not only to show, that, in the above statement, I have not misrepresented his opinion, but because I consider this remarkable circumstance in his literary history as a peculiarly amiable and honorable trait in his character.

"We cannot recall to our memory the ignorance in which we were born: It is a state which leaves no trace behind it. We only recollect our ignorance of those things, the knowledge of which we recollect to have acquired; and to remark what we acquire, some previous knowledge is necessary. That memory which now renders us so sensible of the step from one acquisition to another, cannot remount to the first steps of the progress; on the contrary, it supposes them already made; and hence the origin of our disposition to believe them connate with ourselves. To say that we have learnt to see, to hear, to taste, to smell, to touch, appears a most extraordinary paradox. It seems to us that nature gave us the complete use of our senses the moment she formed them, and that we have always made use of them with

* Voltaire, at an earlier period, had seized completely the scope of Berkeley's theory; and had explained it with equal brevity and precision, in the following passage of his Elements of the Newtonian Philosophy :

"Il faut absolument conclure, que les distances, les grandeurs, les situations, ne sont pas, à proprement parler, des choses visibles, c'est à dire, ne sont pas les objets propres et immédiats de la vue. L'objet propre et immédiat de la vue n'est autre chose que la lumière colorée : tout le reste, nous ne le sentons qu'à la longue et par expérience. Nous apprenons à voir, précisément comme nous apprenons à parler et à lire. La différence est, que l'art de voir est plus facile, et que la nature est également à tous notre maître.

"Les jugemens soudains, presque uniformes, que toutes nos âmes, à un certain age, portent des distances, des grandeurs, des situations, nous font penser, qu'il n'y a qu'à ouvrir les yeux pour voir la manière dont nous voyons. On se trompe, il y faut le secours des autres sens. Si les hommes n'avoient que le sens de la vue, ils n'auroient aucun moyen pour connoître l'étendue en longeur, largeur et profondeur, et un pur esprit ne la connoîtroit peut-être, à moins que Dieu ne la lui révélât."Phys. Newton. Chap. 7.

out study, because we are no longer obliged to study in order to use them. I retained these prejudices at the time I published my Essay on the Origin of Human Knowledge; the reasonings of Locke on a man born blind, to whom the sense of sight was afterwards given, did not undeceive me; and I maintained against this philosopher, that the eye judges naturally of figures, of sizes, of situations, and of distances." Nothing short of his own explicit avowal could have convinced me, that a writer of so high pretensions and of such unquestionable ingenuity as Condillac, had really commenced his metaphysical career under so gross and unaccountable a delu

sion.

In bestowing the praise of originality on Berkeley's Theory of Vision, I do not mean to say, that the whole merit of this Theory is exclusively his own. In this, as in most other cases, it may be presumed, that the progress of the human mind has been gradual: And, in point of fact, it will, on examination, be found, that Berkeley only took up the inquiry where Locke dropped it; following out his principles to their remoter consequences, and placing them in so great a variety of strong and happy lights, as to bring a doctrine till then understood but by a few, within the reach of every intelligent and attentive reader. For my own part, on comparing these two philosophers together, I am at a loss whether most to admire the powerful and penetrating sagacity of the one, or the fertility of invention displayed in the illustrations of the other. What can be more clear and forcible than the statement of Locke, quoted in the Note below; and what an idea does it convey of his superiority to Condillac, when it is considered, that he anticipated à priori the same doctrine which was afterwards confirmed by the fine analysis of Berkeley, and demonstrated by the judicious experiments of Cheselden; while the French metaphysician, with all this accumulation of evidence before him, relapsed into a prejudice transmitted to modern times, from the very infancy of optical science! *

* cc We are farther to consider," says Locke," concerning perception, that the ideas we receive by sensation are often in grown people altered by the judgment, without our taking notice of it. When we set before our eyes a round globe, of any uni

I believe it would be difficult to produce from any writer prior to Locke, an equal number of important facts relating to the intellectual phenomena, as well observed, and as unexceptionably described, as those which I have here brought under my reader's eye. It must appear evident, besides, to all who have studied the subject, that Locke has, in this passage, enunciated, in, terms the most

form color, v. g. gold, alabaster, or jet, it is certain that the idea thereby imprinted in our mind is of a flat circle, variously shadowed, with several degrees of light and brightness coming to our eyes. But we having by use been accustomed to perceive what kind of appearance convex bodies are wont to make in us, what alterations are made in the reflections of light by the difference of the sensible figure of bodies; the judgment presently, by an habitual custom, alters the appearances into their causes, so that, from what truly is variety of shadow or color, recollecting the figure, it makes it pass for a mark of figure, and frames to itself the perception of a convex figure, and an uniform color; when the idea we receive from thence is only a plane variously colored, as is evident in painting.

"But this is not, I think, usual in any of our ideas, but those received by sight; * because sight, the most comprehensive of all our senses, conveying to our minds the ideas of lights and colors, which are peculiar only to that sense; and also the far different ideas of space, figure, or motion, the several varieties whereof change the appearances of its proper objects, viz. light and colors, we bring ourselves by use to judge of the one by the other. This, in many cases, by a settled habit in things whereof we have frequent experience, is performed so constantly and so quick, that we take that for the perception of our sensation, which is an idea formed by our judgment; so that one, viz. that of sensation, serves only to excite the other, and is scarce taken notice of itself: as a man who reads or hears with attention or understanding, takes little notice of the characters or sounds, but of the ideas that are excited in him by them.

"Nor need we wonder that is done with so little notice, if we consider how very quick the actions of the mind are performed, for, as itself is thought to take up no space, to have no extension, so its actions seem to require no time, but many of them seem to be crowded into an instant. speak this in comparison to the actions of the body. Any one may easily observe this his own thoughts, who will take the pains to reflect on them. How, as it were in an instant, do our minds with one glance see all the parts of a demonstration, which may very well be called a long one, if we consider the time it will require to put it into words, and step by step show it to another? Secondly, we shall not be so much surprised, that this is done in us with so little notice, if we consider how the facility which we get of doing things by a custom of doing makes them often pass in us without our notice. Habits, especially such as are begun very early, come at last to produce actions in us, which often escape our observations. How frequently do we in a day cover our eyes with our eye-lids, without perceiving that we are at all in the dark? Men that have by custom got the use of a bye-word, do almost in every sentence pronounce sounds, which, though taken notice of by others, they themselves neither hear nor observe; and, therefore, it is not so strange, that our mind should often change the idea of its sensation into that of its judgment, and make one serve only to excite the other without our taking notice of it." (Locke's Works, Vol. I. p. 123 et seq.)

* Mr. Locke might, however, have remarked something very similar to it in the perceptions of the ear; a very large proportion of its appropriate objects being rather judged of than actually perceived. In the rapidity (for example) of common conversation, how many syllables, and even words, escape the notice of the most attentive hearer; which syllables and words are so quickly supplied from the relation which they bear to the rest of the sentence, that it is quite impossible to distinguish between the audible and the inaudible sounds! A very palpable instance of this occurs in the difficulty experienced by the most acute ear in catching proper names or arithmetical sums, or words borrowed from unknown tongues, the first time they are pronounced.

precise and decided, the same general conclusion concerning the effect of constant and, early habits, which it was the great object of Berkeley's Theory of Vision to establish, and which, indeed, gives to that work its chief value when considered in connexion with the Philosophy of the Human Mind.

Berkeley himself, it is to be observed, by no means lays claim to that complete novelty in his Theory of Vision, which has been ascribed to it by many, who, in all probability, derived their whole information concerning it from the traditional and inexact transcripts of book-making historians. In the introductory sentences of his Essay, he states very clearly and candidly the conclusions of his immediate predecessors on this class of our perceptions; and explains with the greatest precision, in what particulars his own opinion differs from theirs. "It is, I think, agreed by all, that distance, of itself, 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.

"I find it also acknowledged, that the estimate we make of the distance of objects considerably remote, is rather an act of judgment grounded on experience, than of sense. For example, when I perceive a great number of intermediate objects, such as houses, fields, rivers, and the like, which I have experienced to take up a considerable space; I thence form a judgment or conclusion, that the object I see beyond them is at a great distance. Again, when an object appears faint and small, which, at a near distance, I have experienced to make a vigorous and large appearance, I instantly conclude it to be far off. And this, 't is evident, is the result of experience; without which, from the faintness and littleness, I should not have inferred anything concerning the distance of objects.

"But when an object is placed at so near a distance, as that the interval between the eyes bears any sensible proportion to it, it is the received opinion, that the two optic axes, concurring at the object, do there make an angle, by means of which, according as it is greater or less, the object is perceived to be nearer or farther off.