SOURCE: “The Origins of Berkeley's Thought,” in The Development of Berkeley's Philosophy, Russell & Russell, Inc., 1965, pp. 12-67.

[In the following excerpt, Johnston discusses the experiences and influences that resulted in the formation of Berkeley's philosophical theories.]

I. PHILOSOPHICAL AND RELIGIOUS ENVIRONMENT

It is the merest commonplace to say that every thinker owes much to his predecessors and contemporaries. His thought is consciously influenced by philosophers, scientists and moralists; and, in addition, it bears upon it the stamp of that subtler but none the less potent force, the social environment in which he lives. Berkeley is perhaps the freshest and most original thinker in the history of British philosophy; yet, more than any other, he was influenced both by his immediate philosophical predecessors and by the social surroundings in which he was placed. He was aware of his debt, though not, perhaps, of the full extent of it. “I must acknowledge myself beholding to the philosophers who have gone before me,”¹ he reminds himself in the Commonplace Book; but at the same time he compares these predecessors to adventurers, “who, tho' they attained not the desired port, they by their wrecks have made known the rocks and sands, whereby the passage of aftercomers is made more secure and easy.”² But Berkeley's indebtedness was not merely of this negative kind. He did not use other philosophers merely as beacons to enable him to keep clear of the errors on which their thought had been wrecked. This metaphor is entirely inadequate. In reality, other philosophers formed his spiritual meat and drink, and it was because he assimilated so well the nourishment they provided that he was able to reach the philosophical stature to which he actually grew.

In Berkeley's case it is possible, with greater certainty than is usual, to discover the material which his receptive mind acquired from his predecessors and contemporaries, and, in general, to trace the outlines of the main formative influences which played upon his mind. When his first book appeared, he was still very young. He was only twenty-four when the New Theory of Vision was published, and the Principles was given to the world in the following year. In these works he makes no effort to conceal the sources from which the New Principle was derived. One of his great aims, he tells us, is to “remove the mist or veil of words” by which philosophy is obscured, and he has no wish to hide the origins of his own thought or mask the workings of his own mind. His own consciousness of his relations of attraction and repulsion to other philosophers renders the determination by us of the extent and nature of those relations, if not an easy task, at least a practicable one. A Locke, a Kant, or a Hobbes, who does not produce his work till near the evening of his days, finds it impossible to say which among the myriad influences to which he has been exposed have really been vital in the formation of his mind. And it is often equally impossible for the historian to disentangle the various threads which have been woven so closely into the texture of the particular philosophy. But Berkeley's enduring philosophical work was nearly all done when he was a very young man, and while the impressions of his student-days were still fresh and vivid. It is thus possible for us to trace, from his own writings, the influence of his social and philosophical environment on the development of his thought.

What we have to do, then, is to study the evolution of Berkeley's philosophy, and, as no study of evolution is complete without some investigation of environment, it is necessary to sketch in outline the nature of the environment of mental and moral forces with which Berkeley was surrounded during his student-days at Trinity College, Dublin.

In his College days or earlier Berkeley encountered the two great influences which affected the whole course of his life and work. The one aim which he kept persistently before him through all the vicissitudes of a varied life was the refutation of deists and free-thinkers. Now, in the formation of this purpose and in the preparation for carrying it out, he was affected by two main influences or sets of influences, one religious, the other philosophical. He was influenced not only by the new experimental philosophy of mind and nature introduced by Newton and Locke, but also by the great religious controversy, which lasted over half-a-century, between orthodoxy and deism.

When Berkeley went to Dublin, the great deist controversy, in which he was destined to play a not unimportant part, was just beginning. In 1696 the flame was fairly lit by John Toland with his anonymous book, Christianity not Mysterious. The publication immediately became notorious, and a second edition bearing Toland's name was issued in the same year. In the spring of 1697 Toland went to Ireland, his native country, and discovered that intense excitement had already been caused by his book. He did everything to encourage it. In tavern and coffee-house he never wearied of airing his views and repeating his main arguments. His skill in debate won many to his side, and Authority considered it necessary to institute a vigorous campaign against him.³ Everything possible was done to crush his views. State, Church, and University were all arrayed against him. Dr. Peter Browne,⁴ at that time Provost of Trinity, published a violent attack on his views,⁵ in which he endeavoured to excite a popular outcry against him.⁶ The Church was not behind in lending its voice to the general condemnation, and from every pulpit, by Archbishop and curate, Toland and his views were denounced.⁷ The affair was even taken up by the Irish Parliament, a special commission was appointed to deal with it, and eventually a resolution was passed by the whole House declaring the book to be antagonistic to the Christian religion and the Established Church, and decreeing that it should be publicly burnt by the common hangman, and the author arrested by the Serjeant at Arms. Toland fled. But the controversy which he had popularised was not so easily got rid of, and when Berkeley entered Trinity College in 1700 free-thinking was still a subject of the keenest debate. From the beginning Berkeley took the greatest interest in the controversy, and definitely ranged himself on the side of the orthodox.⁸

Berkeley's Dublin environment was also responsible for leading him in the direction in which the work was to be done that would secure for him a permanent reputation. If his work had consisted simply in the refutation of the deists, he would now be as much ignored as they are. His reputation rests on his philosophy pure and simple, and the general character of his philosophy was determined by his early studies at Trinity College. The College in which he lived had changed greatly since Swift's student-days. Swift took his degree in 1685, after wrestling contemptuously with the “Logics” of Burgersdicius, Keckermannus and Smiglecius and the “Manuals” of Baronius and Scheiblerus. But by Berkeley's time these tomes had been discarded from the curriculum, and very little attention was paid to the subtleties of the Schools. Trinity College had given a welcome to Locke's Essay, published in 1690, and Newton's Principia, published in 1687; and all interest was now concentrated on the new philosophy initiated by them. Thus, when Berkeley became a student in 1700, Locke and Newton were the great intellectual forces in his environment. Berkeley became greatly interested in both thinkers, and in 1706 he was the leading member of a society which met weekly for the discussion of their views.

This society, which was founded on January 10, 1705/6, consisted originally of eight persons only; and there is some reason to suppose that Berkeley was president and Samuel Molyneux (son of Locke's friend) secretary.⁹ Though the statutes of this society, which are preserved in Berkeley's Commonplace Book, are rather elaborate, yet, oddly enough, the object of the society is not stated. It was clearly to be very comprehensive, members being entitled to “propose to the assembly their inventions, new thoughts, or observations in any of the sciences.”¹⁰ The constitution provides for a museum, with one of the members as “Keeper of the Rarities”; and it is clear from some entries which immediately follow the statutes in Berkeley's Commonplace Book that Locke was the subject of much discussion. Directly after these entries follows another list of statutes, a short one this time, which is dated December 7, 1706. These statutes may refer to a new society, but it is more probable that they merely correct or amplify the constitution of the original society. The object of the society is now defined. It is “to discourse on some part of the new philosophy.”¹¹

In this society, accordingly, Berkeley discussed with his friends the New Philosophy of Locke and Newton; and in connection with these discussions, he wrote his Commonplace Book.

II. THE COMMONPLACE BOOK

The Commonplace Book is in itself of unique philosophical interest, and is, in addition, of the utmost value for the light it throws on the genesis, evolution, and affiliation of Berkeley's thought. Begun early in 1706, the book contains a full and suggestive series of notes of what he was reading and thinking and planning during the earliest years of his philosophical development. In its vivid, disjointed, and staccato jottings it reveals a mind pregnant with a great discovery. More important still, it displays the sources from which that great discovery was nourished prior to being brought forth in the New Theory of Vision and Principles, and enables us to discern the emotions which, in Berkeley's mind, accompanied the birth of the New Principle. The notebook was intended for the eye of its writer alone, and it contains the freest possible expression of his attitude towards the philosophers and mathematicians from whom he was still learning. Its casual and unstudied utterances throw a brilliant light on the origin and progress of his thought.

The earliest philosophical remarks in the book are the queries interposed between the statutes of January 1705/6 and December 1706. These have reference, without exception, to particular points of Locke's doctrine. Several isolated questions refer to matters which Berkeley was later to raise, though they have little connection with the fundamentals of his own theory; but more interesting than these are the important queries which indicate that already Berkeley's mind was tending in the direction of the New Principle. Suggestive, for instance, is the very first entry, “Query. Whether number be in the objects without the mind? Locke, b. 2, c. 8, s. 9.”¹² Berkeley's conviction of the mind-dependent reality of the world was already dawning; and that he was thus early inclining to the emphasis on sense which is so marked a feature of his earlier thought is evident from the tentative and awkwardly expressed statement, “Things belonging to reflection are for the most part expressed by forms borrowed from things sensible.”¹³ But such suggestions as these are merely prolegomena to the New Principle: the New Principle itself has not yet been revealed to Berkeley's ardent mind.

The revelation takes place in the most striking way in the next group of entries. As we read the phrases they contain, it needs no effort of imagination to reconstruct the stages of the development of the New Idea. No harsh Socratic maieutic was needed to bring it to the birth; it came to light easily and almost imperceptibly, and as we scan the sentences in which Berkeley indicated the process, it is easy to sympathise with his joy and surprise as he gazes at the child of his mind—“The obvious tho' amazing truth.”

The whole process of evolution takes place in a single page, and that the first page of the Commonplace Book proper.¹⁴ Berkeley is considering the problem of time and eternity, and after one or two remarks of no particular importance, he makes the significant statement, “Time is the train of ideas succeeding each other.”¹⁵ Next he says, “Duration not distinguished from existence.” Time, he means, exists only so long as it endures. The existence of time is its duration and nothing else; hence, in general (this seems to be his argument), existence is identical with duration. But the difficulty arises that, if this be so, we seem to be deprived of any objective measure of existence. In pain time is longer than it is in pleasure. Because its duration is longer, its existence is longer. The conclusion would seem to follow that the measure of time, and consequently the measure of existence, differs from individual to individual, and in the same individual from moment to moment. This consequence is, in part, admitted by Berkeley. “The same τò ν[UNK]ν,” he says, “not common to all intelligences.” There is no objective or universal measure of time, and the conclusion must be drawn, “Time a sensation; therefore onely in ye mind.” This conclusion is obviously of the first importance in the development of Berkeley's philosophy. Time, he has been forced to state, has no existence in itself or in an external world of things. It is simply a sensation or series of sensations, and is thus entirely dependent on the mind. But much more than this is implied. Berkeley has already declared that duration and existence are identical, and the tremendous conclusion follows that all existence is mind-dependent. Time is a sensation, or, as he elsewhere says, a perception … tempus est percipi; and existence itself is simply a perception or series of perceptions … esse est percipi. That is the first part of Berkeley's New Principle.

In the next few entries Berkeley confirms and extends “this amazing truth.” Extension, he declares, is a sensation, “therefore not without the mind.” And in general we may proceed to affirm, “Primary ideas proved not to exist in matter; after the same manner that secondary ones are proved not to exist therein.” Primary ideas, equally with secondary ones (which Locke and others had proved to be dependent on perception), are mind-dependent. Hence the great conclusion is confirmed that the whole world depends on thought. “World without thought is nec quid, nec quantum, nec quale, etc.” The world owes its determinate existence to the fact that it is an object of thought or perception. In being perceived it exists. Hence the source of existence must be in that on which existence depends, and that is consciousness. Consciousness, then, is the only real existence, for the things which owe their being to it have a merely derivative existence. And the conclusion follows that “Nothing properly but Persons, i.e. conscious things, do exist.” Existence, then, is of two kinds: in its primary sense it means “perceiving,” in a secondary sense it means “being perceived.” We may accordingly state the universal and comprehensive truth esse est aut percipere aut percipi.

This is, in essence, the kernel of Berkeley's theory of knowledge and existence. The evolution—and it is a real evolution—is complete in the first page of the Commonplace Book.

But no sooner had Berkeley reached this conclusion (and indeed before he reached it), than difficulties came crowding into his mind. Nothing, I think, in the whole course of Berkeley's work leaves such an impression of freshness, vitality, and vigour, as the early pages of the Commonplace Book. His mind was literally open to the world, problems of all kinds impinged upon it from every direction, and, now that he had discovered his New Principle, it was essential that all these problems should be considered with reference to it, and in the light which it had to give.

These problems fall naturally into three classes: they are either religious, psychological, or mathematical. As an example of the way in which problems literally overwhelm him, it may be of interest simply to enumerate some of the points which he mentions and considers in the first two pages of the Commonplace Book. (1) Religious. Immortality, the wisdom of God, the fall of Adam, the knowability of the soul, and the proofs of the being of God. (2) Psychological. The nature of primary and secondary qualities, the question whether a blind man made to see would know motion at first sight, the nature of colour, the relation of visual and tactual qualities, and the query of Molyneux whether a born-blind man made to see would know a cube or sphere at first sight. (3) Mathematical. The infinite divisibility of time and space, the nature of motion, and the question whether the incommensurability of the side and diagonal of the square is compatible with the New Principle. Most of these special difficulties, many of them of the first importance in themselves and with reference to his theory, were dealt with in detail by him subsequently: the impressive thing about their appearance here is just the fact that they do appear. Berkeley's instinct for the important elements was not at fault; for as early as this he descried the obstacles and hazards in the way of the exposition of the Philosophy of the New Principle.

In the rest of the Commonplace Book the New Principle is turned over and over in Berkeley's mind, scrutinised from every possible point of view, examined in the light of all the reading he could bring to bear upon it, and defended against the attacks of imaginary critics. In these pages there is naturally much repetition, for the same difficulties recur again and again. But the repetition is, like Kant's, never entirely negligible. The same fundamental ideas are advanced in slightly different settings, for they have been suggested in slightly different ways.

The development of what is commonly known as the Berkeleian theory is in essentials completed, as we have seen, in the first few lines of the Commonplace Book, and it is unnecessary to trace in any great detail the progress of Berkeley's thought in the remaining pages. The precise way in which he dealt with the various difficulties which confronted the New Principle will be treated subsequently. In the meantime it will be sufficient to indicate, in the briefest outline, the order in which the various problems seem to have become prominent in his mind.

The general problem which first occupies him is the nature of extension. He has already concluded that extension is simply a collection of ideas; but this conclusion, he soon realises, teems with important and difficult problems. What, for example, is the relation of visible extension to tangible extension?—and the relation of either or both to reality? Again, since the existence of extension consists in being perceived, what becomes of it when it is not being perceived? Has extension any permanence? And further, what is the relation of the extension that I perceive to the extension that you perceive? Has extension any self-identity? Lastly, if extension consists of discrete ideas, particular perceptions, what do we mean by speaking of its continuity? (pp. 60-63).

These problems of permanence, identity and continuity are next considered in relation to persons. The existence, permanence, and the like of the external world, Berkeley believes, depend on the perception of persons; and it is therefore obviously important to examine the grounds on which we ascribe existence to persons. If the existence of persons consists in perceiving, what becomes of them when they are not actually perceiving? Does it follow that “men die, or are in a state of annihilation, oft in a day?” Or, if we say that identity of personality consists in the will, and that the will is continuously active, what is the relation of the finite will to the will of God? Is its existence swallowed up in God as the ultimate power of perception and action, or does it enjoy a distinct and particular permanence and reality? (pp. 64-72).

The next main group of problems is concerned with the perception of distance and magnitude. Questions relating to perception have, as we have seen, already been raised by Berkeley, but he does not become preoccupied with them till p. 72. On that page he states in successive entries the two fundamental points in his theory of vision, viz. that there is no necessary connection between optic angles and extension, and that distance is not immediately perceived by sight. The relation, he goes on to point out, between visual signs and the distance or magnitude they suggest is, though constant association leads us to imagine it to be necessary, really only an arbitrary one. We never immediately perceive distance or magnitude. They can only be inferred by us, for they are suggested to us by the signs which, in our experience, uniformly accompany them¹⁶ (pp. 72-82).

In the next few pages Berkeley's mind is, in spite of many distractions, occupied in the main with mathematics. The mathematical doctrine of the nature of infinitesimals was perhaps the most difficult obstacle with which his theory had to contend, and it is clear that he read widely in contemporary mathematics with a view to the discovery of a means of overcoming the difficulty. The pages in which he deals with mathematics are the most unsatisfactory in the whole Commonplace Book. He saw clearly that, if extension consists of minima sensibilia, then of course infinite divisibility is impossible, and the recently discovered and generally accepted mathematical doctrine of infinitesimals must be branded a fiction. Not only so, but it would have to be asserted that the bisection of a line is possible only when it consists of an even number of minima sensibilia, and the time-honoured theorem that the side and diagonal of a square are incommensurable would have to be denied. Berkeley accordingly devotes much time to a discussion of these and kindred difficulties (pp. 83-89, 7-14).

In the rest of the book no one group of problems occupies his attention for any length of time. It is noteworthy, however, that psychological questions are almost excluded, no doubt because by this time the New Theory of Vision was already in manuscript; and Berkeley's attention is devoted to rethinking, in all its aspects and implications, the New Principle which he was preparing to publish to the world in the Principles. He was thinking a good deal about the relation of the New Principle to religion and morality, he was working out a conception of will and soul that he intended to expound in a subsequent volume of the Principles, he was diligently drafting important paragraphs for the Introduction to the Principles, and he was reading and re-reading Locke, Newton, Descartes, Malebranche, Hobbes, Spinoza and others, in order to see what criticisms could be brought against his theory from their standpoints (pp. 15-58).

We have now indicated, as far as it is possible to do so with brevity, the origin of Berkeley's philosophy, and the general order in which he considered the problems to which it gave rise. So far, we have not said anything in detail of his relation to other thinkers, and of the extent to which he was influenced by them. And we now proceed to state, in some detail, the points at which his thought seems to have been influenced by other philosophers. In doing this our method will be strictly historical. We will not go beyond the data supplied by the Commonplace Book, and one or two slight contemporary writings; and, as our method is historical, discussion and criticism of the various theories will be postponed to subsequent chapters. Here we are concerned simply to state seriatim the various points of relation and lines of influence.

In the Commonplace Book we find three main sources of Berkeley's philosophy, or perhaps it would be better to say, three main lines of influence on the development of his thought. These were (1) Locke, (2) the Cartesians, especially Malebranche, and (3) Newton and other contemporary mathematicians. Of these Locke is by far the most important. It might, indeed, be proper to claim that he is the only real source of Berkeley's philosophy, and to regard the others as contributing only formative influences. From Locke only did he really derive anything of the first importance. The original impulse and direction of his philosophy came from Locke, and from Locke also the great Gemeingut of ideas which makes the continuity between them as remarkable as their differences.

In the following three sections of this chapter, we shall examine the influence of (1) Locke, (2) the Cartesians, and (3) contemporary mathematicians on the development of Berkeley's thought, especially as it is revealed in the Commonplace Book.

III. THE INFLUENCE OF LOCKE

That the mind of Locke exercised an almost magisterial influence on Berkeley is indisputable. But Berkeley was by no means willing to take everything on trust from his master. His admiration was tempered by criticism. Thus, his relation to Locke is one both of attraction and repulsion. This double attitude is manifest at almost every point at which Berkeley came into contact with Locke.

To speak first of the method of philosophy. At first Berkeley here followed Locke implicitly. Locke's method is empirical and psychological. He makes an inventory of the actual contents of human experience, and holds that, as our knowledge is wholly derived from experience, philosophy must consist simply in an analysis of that experience.

Locke himself describes his method and aim very clearly in the Second Letter to Stillingfleet. “If I have done anything new,” he says, “it has been to describe to others, more particularly than has been done before, what it is that their minds do when they perform the action that they call knowing.” The a priori methods of scholasticism had been discredited in natural science; and it seemed probable that the methods of observation and analysis which had proved so fruitful in physical enquiries would, if applied to “inner experience” as their subject-matter, lead to equally successful results. Thus “inner experience” as well as “outer experience” is matter for scientific treatment. In the latter case the enquiry gives rise to the various special sciences; in the former to mental science or philosophy. Observation as directed upon inner experience is introspection, the chief method of philosophy, which Locke defined as the process of “looking into the mind to see how it works.”

Berkeley's method is at first, like Locke's, entirely introspective. His objection to Locke is not that he used the method of introspection, but that he did not use it enough. Locke, like other philosophers, had been misled by words, and had been content to take words at their face-value without trying to verify their real meaning. Let Locke and his followers, Berkeley urges, examine their own experience, and they will find that the abstract ideas which they posit have no real existence corresponding to the words which name them. Hence, as the panacea for incorrect thinking Berkeley advocates introspection, or, as he sometimes terms it, using a scholastic word, introversion. “Consult, ransack your understanding,” he says.¹⁷ And he is as good as his injunction. For most of the jottings in the Commonplace Book are the result of his own application of the introspective method to his own experience.

Hence for Berkeley the only real philosophy is empirical. “Mem.,” he says, “much to recommend and approve of experimental philosophy.”¹⁸ The New Theory of Vision is wholly psychological, and in the Principles he claims that his results are based entirely on his analysis of his own experience: in both cases he advises the reader to confirm the doctrines expounded by examining his experience.¹⁹ We should base our philosophy, he insists, on our own observation of our own experience. “There is nothing more requisite than an attentive perception of what passes in my own understanding.”²⁰ In philosophy it is vain, he declares, to postulate anything which we do not find in our analysis of our own experience.

But though Berkeley thus follows Locke's methodology, he goes further than his master. He goes further by going back to investigate the foundations of science and the roots of knowledge.²¹ He believes that philosophers like Locke have occupied a vast tract of country, but they have not been sufficiently careful to establish their base and organise their lines of communication. They have not possessed their possessions. Thus the territory that they discovered needs re-discovery and development. Or, to vary the metaphor, the ground which they tilled extensively, and whose produce they thought they had exhausted, can be made to yield still richer and more abundant fruit by the application of intensive methods of cultivation.

Berkeley believes in the need of a critical regress on current methods and assumptions. Locke, indeed, had criticised the scholastic presuppositions which were still implied in much of the philosophy of the day; and, in particular, had destroyed the hoary doctrine of innate ideas. But his criticism had not, Berkeley maintains, been sufficiently radical, and thus many of the old errors were still suffered to persist. The notable instance of an error which had not only not been removed by Locke, but which he actually took pains to reinforce with new arguments of his own was the doctrine of abstract ideas. Locke's acceptance and confirmation of that doctrine is, in Berkeley's view, his greatest mistake, and one which seriously affects the value of the critical method. And in Berkeley's eyes his own great methodological reform consists in driving back the critical regress which had been started by Locke beyond the point reached by him; and in showing that any conception of abstract ideas formed according to the currently accepted theories must be avoided by a true philosophical method.

But in spite of this important difference, a difference which greatly affects the results and ultimate orientation of the two systems, Berkeley agrees with Locke that the great philosophical method is that of observation and introspection. Berkeley is, in fact, a more consistent Locke. All our philosophical, conclusions must be based, he insists, on our examination of experience.

Up to a certain point, Berkeley also follows Locke in his view of the result of this examination of experience. At first his inventory of the contents of the mind is very similar to Locke's. With Locke he agrees, at least at first, that “all knowledge [is] onely about ideas.”²² Now for Locke “idea” means, in the oft-quoted definition, “whatsoever is the object of the understanding when a man thinks.” In this definition “thinking” covers both senseperception and reflection. Ideas of sensation are produced by external objects, ideas of reflection by the operations of the mind; but both ideas of sensation and ideas of reflection may be called the objects of the mind. This in outline is Locke's theory of knowledge.

Now, a good deal of misunderstanding of Locke's view has arisen from not keeping carefully in mind a point which, it must be admitted, Locke did not make sufficiently clear; and, if we are to understand Berkeley's relation to him, his theory must be explained with some care.

For Locke, an idea of sensation is one produced by an external object on the senses. But an idea of reflection is produced by the operation of the mind on what Locke calls “internal sense.” In each case the preposition “of” indicates the source from which the idea comes. On the other hand, when Locke speaks of an idea of blue, “blue” refers to the object which gives rise to the idea. An idea of blue may be either an idea of sensation or an idea of reflection, according as it is produced by direct stimulation by an external object, or by the representative operation of the mind. Locke calls the idea the object of the mind, but he also calls the external thing the object of the mind. On his view, if we analyse any process of perception, we really have three elements, (i) the external thing, (ii) the idea which results from the perception of the external thing by the mind, and (iii) the mind for which the idea becomes an object. The idea thus occupies an intermediate position between the mind and the thing. “It is evident the mind knows not things immediately, but only by the intervention of the ideas it has of them.”²³

To formulate in exact and precise terms Locke's conception of the relation of the idea to the mind on the one hand, and to the thing on the other, is exceedingly difficult, if not impossible. But it is possible to say what he did not mean. (1) The relation between mind and idea is not that of substance and attribute, nor of phenomenon and noumenon, nor of appearance and reality. All these statements of the relation involve metaphysical theories foreign to Locke. The best statement of the relation, and one sanctioned by Locke, regards the idea as the copy of the thing. But only some ideas (those of primary qualities) are copies of things. (2) The difficulty of stating the relation of the idea and the mind is equally great. Locke constantly speaks of ideas as “in the mind.” But it is a mistake to say that, for Locke, ideas are “states of consciousness” or “mental affections.” He does not dream of saying that we know only our own states of consciousness. Nor is an idea a “mental affection.” Malebranche had raised the question of the relation of a mental modification or affection to an idea. In the Essay Locke does not touch the problem at all, and in his criticism of Malebranche²⁴ he does not seem to see that there is a problem. To say that the idea is “mental” would suggest an opposition which was absent from Locke's mind between “mental” and “non-mental.” In so far as an idea is said to be in the mind, it would seem to be mental; but as the object of the understanding, that which is perceived, it would seem to be non-mental, though on a different level from the physical object. But Locke does not seem to have asked himself whether an idea is mental or non-mental. He was content simply to say that it is the object of the understanding. Thus the fundamental fact, and that in which Locke is mainly interested, is that in the widest sense the idea is (i) the copy of the thing, and (ii) the object of the mind.

Berkeley at first, in his zeal “to simplify and abridge the labour of study,” thought of denying the existence of both minds and things. Only ideas would be left. Of different kinds, and in various combinations, they alone would constitute the whole of experience. But though Berkeley actually suggests the banishment of both minds and external things, he insists upon it only in the case of external things.

He had what seemed to him excellent reasons for denying the existence of external things, and indeed his criticism of Locke left him no option. Locke's account of the “original” of knowledge, Berkeley maintains, is untenable. His view of the relation of idea and thing as that of copy and thing copied is impossible, because if the mind is confined to knowledge of its own ideas, “it can compare nothing but its own ideas.”²⁵ In order to test the truth of its own ideas, the mind ought to be able to compare them with the things which they copy. But this is impossible, (a) because the idea can be like nothing but another idea,²⁶ and (b) because the mind, on Locke's view, is incapable of knowing things without the medium of ideas.²⁷ Further, since external material things cannot be known directly, it will be necessary to show that they perform some useful practical function, if we are to be justified in retaining them even as postulates. But Locke's own account of material substance shows how incapable material things are of undertaking the task he has assigned to them, for, as in his view matter is wholly passive, it is unable actively to produce ideas in us. Berkeley accordingly thinks that, since Locke's external things have been shown to be theoretically unknowable and practically useless, we are justified in applying Occam's Razor, and retaining ideas only. He has no objection to calling ideas “things,” though “thing” is wider than “idea,” provided we do not import into the term “thing” any notion of material existence.²⁸ And he protests against the use of the phrase, “idea of something,” on the ground that it implies the false suggestion that the idea and the thing are different.²⁹ For Berkeley the idea is the thing perceived, and the thing perceived is the idea. “By idea I mean any sensible or imaginable thing.”³⁰ The problem of the relation of idea and thing thus becomes non-existent, for they are identical.

Not so the question of the mind's relation to its ideas. That is a real problem. Berkeley speaks, as Locke had done, of ideas being “in the mind,” and once or twice even suggests that the mind is nothing but these constituent ideas. He very soon abandoned that theory, but there is some justification for the view that in the Commonplace Book an idea is regarded as some kind of mental modification. Yet in the Commonplace Book we also have the reiterated assertion that the idea is the object of the mind.³¹ “The house itself, the church itself, is an idea, i.e. an object—immediate object—of thought.”³² To Berkeley's treatment of this problem we must return later. In the meantime it is sufficient to note that the important thing for Berkeley is that the universe consists solely of minds and ideas.

His study of Locke's and Descartes' theory of primary and secondary qualities also helped to lead him to this conclusion. Locke, largely following Descartes, had developed the distinction between primary and secondary qualities. Primary qualities are extension, solidity, figure, number, motion and rest. All others are secondary. Primary or real qualities actually belong to the thing, whether it is perceived or not; but secondary or imputed qualities do not inhere in the thing, but depend for their existence on our perception of them. Only in the case of primary qualities is the idea like the original. “Their patterns do really exist in the bodies themselves.” But with secondary qualities, “there is nothing like our ideas existing in the bodies themselves.”³³ Ideas of secondary qualities are entirely dependent on the mind which perceives them. Now Berkeley points out that Locke's arguments for the mind-dependent existence of secondary qualities may be applied also to primary qualities.³⁴ He holds that Locke has failed to make out a case for the different treatment of primary and secondary qualities, and maintains that ideas of primary qualities must be reduced to the same level as ideas of secondary qualities. Both alike are entirely dependent on being perceived; and the only reality is mind and its ideas.

But Berkeley insists that this is reality. He admits, indeed, that at first sight his argument against the independent existence of primary qualities seems to deprive us of reality. The reality of extension, figure, solidity and so on seems to have vanished. But this is only in seeming. Berkeley maintains that his theory conserves reality, and he is inclined to think that it is the only one that does.³⁵

Berkeley's theory of reality, like his theory of knowledge, is very closely connected with Locke's doctrine, and, if we would understand its significance, we must examine how Berkeley developed it by criticism of Locke.

Locke's doctrine of reality follows directly from his theory of knowledge. For Locke the only objects of knowledge are ideas; and ideas, distinguished according to their source, may be classified, as we have already pointed out, as ideas of sensation or ideas of reflection. But there is another distinction drawn by Locke, to which, though it is of great importance, we have not yet paid attention. That is the distinction between simple ideas and complex ideas. Simple ideas are the ultimate unanalysable elements of all knowledge, and in its apprehension of them the mind is wholly passive and receptive. On the other hand, in complex ideas, which result from the union or composition of several simple ideas, the active operation of the mind is displayed. Regarding simple ideas as the material and foundation of all knowledge, the mind combines, by determinate processes, certain of them which are regularly found together in our experience into aggregates or compounds; and to each of the complex ideas thus formed we assign a name, and come to regard it as representing one thing.

Now, this would be impossible, said Locke, unless some “substance” existed to account for the coherence of simple ideas. Without some support or substratum simple ideas would fall apart; and, if nothing but simple ideas existed, knowledge would not be possible, for knowledge depends on the practicability of combining and compounding them. Thus reality depends on substance: substance is the support or substratum of real things, and without this substratum permanence and self-identity, the two ultimate characteristics of reality, would not be possible.

What, then, is substance, which apparently discharges an indispensable function in the universe? Locke admitted that he could give no account of it. We no more know what the substratum or support of things is than the Indian philosopher did who declared that the world is supported by an elephant, the elephant by a tortoise, and the tortoise by—he knew not what. Substance, then, is an obscure idea of somewhat—we know not what.³⁶

At first Berkeley seems simply to have taken over this conception from Locke. Thus in one of his early entries he claims that he has demonstrative knowledge of the existence of bodies, meaning by “bodies” “combinations of powers in an unknown substratum.”³⁷ But from such a conception of an unknown support of qualities or powers he very soon emancipated himself.

Against the view he brings the very natural argument that, as we can in no way know the support or substratum, and as it performs no indispensable function, it is quite unnecessary to assume it. The reason why no account can be given of this substratum is not that it is obscure, as Locke supposed, but that it is non-existent. And Berkeley suggests that all we mean by the substance of a thing is “the collection of concrete ideas included in that thing.”³⁸ In this sense, Berkeley allows, we may still speak of the substance of a thing. But substance in general, or the abstract idea of substance, is nothing but a philosophical fiction.

Granted, then, that Locke's substance is an impossibility, what gives permanence and reality to things? At first Berkeley was inclined to assume the existence of certain mysterious powers to perform this function.³⁹ But he soon recognised that such powers, of which we can give no account, are in no better case than Locke's substance, and if Locke's substance be abandoned, these obscure powers cannot be retained.

The conclusion to which Berkeley is finally driven is that the reality of things rests on no substance or set of powers, but depends on being perceived. This is what Berkeley regards as his great discovery—esse est percipi. That this conviction dawned on him very early in his philosophical development has already been pointed out; but it is interesting to notice that this, which is usually regarded as the most original element in his whole philosophy, had already been suggested by Locke. “When ideas are in our minds,” said Locke, “we consider them as being actually there, … which is that they exist or have existence.”⁴⁰ For Locke the esse of ideas is percipi. Now, Berkeley held, as we have seen, that things are simply collections of ideas, and therefore, adopting Locke's view of the esse of ideas and applying it universally, he reaches the conclusion that the esse of all collections of ideas, i.e. all things, is percipi. The general principle may, therefore, be stated as esse est percipi.

But this definition, Berkeley sees, is not sufficiently comprehensive. It is true only of one of the two classes into which Locke divided things. Locke drew a distinction sharp on the whole between active things and passive things. Passive things are those which are not self-subsistent, but depend on something outside themselves, while active things are self-supporting and substantial. It should not be overlooked that this distinction, which is of the utmost importance in Berkeley's philosophy, is simply taken over by him from Locke.⁴¹ Berkeley, of course, translates it into his own terminology, and holds that while passive things depend on being perceived, the existence of active things (or persons) consists not in being perceived but in perceiving. Thus the complete definition of existence is as follows: “Existence is percipi or percipere.”⁴²

Hence the pivot of Berkeley's whole doctrine of reality is the mind. Active things exist as percipient, i.e. as minds; and passive things exist as objects of perception, i.e. as dependent on the mind. All reality, then, is connected with the mind, and it is obviously of the greatest importance for Berkeley's theory of reality to know exactly what the mind is. In his investigation of the meaning of the mind, he again has recourse to a consideration of Locke's theory.

To the question What is the mind? Locke had given two distinct answers, both of which occupied Berkeley's attention.

(1) The mind is, on Locke's view, apart from experience, a piece of white paper whose blanks have yet to be filled. It is a tabula rasa on which ideas must be impressed ab extra. In perception the mind is thus purely passive; it depends for its knowledge wholly on what it receives from the external world, and it can exercise no active function at all.⁴³ Locke disagrees with the Cartesian view that because it is the essence of the mind to think therefore the mind always thinks. “Every drowsy nod shakes their doctrine, who teach that the soul is always thinking.”⁴⁴ Berkeley criticises Locke,⁴⁵ and returns to the Cartesian theory, for he sees clearly Locke's inconsistency. If the mind is purely passive, how does it come by complex ideas? Can the piece of white paper make marks upon itself? Complex ideas are the result of the voluntary operation of the mind in dealing with simple ideas impressed upon it in perception. But a mind which voluntarily operates cannot be passive.

(2) On the other hand, Locke holds also that the mind is a complex spiritual substance.⁴⁶ When he speaks of the activity of the mind, he is usually thinking of this theory. He holds that the same arguments as lead to the belief in material substance justify our belief in spiritual substance, for only those whose thoughts are immersed in matter find it more difficult to conceive spiritual than material substance.

This theory also influenced Berkeley. He had denied the existence of material substance, maintaining that a thing is nothing but a collection of sensible qualities; and he was inclined to think that consistency required him to deny the existence also of spiritual substance, and affirm that the mind is only an aggregate of ideas. In the Commonplace Book he actually suggests this, and thus anticipates Hume in reducing his theory to consistency “Mind,” he says, “is a congeries of perceptions. Take away perceptions and you take away the mind. Put the perceptions and you put the mind.”⁴⁷ He means to deny, as Hume afterwards did, that there is any entity apart from ideas, and asserts roundly that the understanding is simply perceptions and the will nothing but volitions. Self, soul, understanding, will, are merely names for collections of ideas or volitions. Apart from these ideas and volitions, which wholly constitute them, they have no existence.⁴⁸

Though Berkeley reiterates this view and is apparently satisfied with its theoretical consistency, certain practical considerations made it impossible for him to rest in it. Is it quite certain, he asks, that the understanding is nothing over and above its perceptions? Still more, “what must one think of the will and passions?”⁴⁹ Is the will, as Hume was later to say, nothing but the passions? Berkeley's moral and religious interest prevented his believing this. The will must be distinct from, and superior to, the passions. The understanding is more than the ideas. Both understanding and will are active and may be identified with one another and with spirit. But Berkeley prefers to regard understanding and will as at least verbally distinct. “The concrete of the will and understanding I might call mind.”⁵⁰ Mind as an entity must exist.

Berkeley was led to the same conclusion by the consideration of the problem of the unity of experience. If there is no matter, but only sensible qualities, and if there is no mind, but only fleeting ideas, how can mind have any unity? I cannot even speak of my ideas, because I do not exist apart from the succession of ideas. An experience of this sort would be utter chaos. “What mean you,” Berkeley asks, “by my perceptions, my volitions?”⁵¹ Berkeley sees that it is necessary to postulate the existence of a personal self to guarantee the unity of experience. But he deliberately avoided giving any account of the meaning of personality. “Mem.,” he says, “carefully to omit defining of person, or making much mention of it.”⁵²

Still another point impressed upon Berkeley the necessity of a permanent mind or self. As we have seen, ideas are passive, “impotent things.” Hence an active mind is necessary to bring them into complexes and manipulate them. A collection of ideas by itself will always remain passive. Thus the active mind or spirit must be more than any idea or congeries of ideas.

But the problem of identity and permanence must be probed further. Granted that there are minds, and that existence means simply perceiving and being perceived, what account can we give of the permanence and identity of ideas or things and of minds or persons? Neither persons nor things have identity, if identity means durational continuity. Berkeley is at first inclined to give up the permanence both of things and persons, and he is thus forced to seek some other ground for their identity. With regard to things, he points out that their existence is often interrupted by “divers beginnings and endings.”⁵³ Ideas are particular perishing existents. Nor do persons have an uninterrupted existence.⁵⁴ The mind does not exist in sleep.⁵⁵ The mind exists only so long as it is actually perceiving, and things exist only when they are being perceived. But Berkeley's efforts to find any adequate ground for the identity of persons and things, after making this admission, proved fruitless; and he was therefore compelled to retrace his steps and attempt to establish the permanence both of things and persons. In dealing with persons, he simply reaffirmed, against Locke, the Cartesian view that the mind always thinks. Even in sleep the mind is active, and thus the mind as thinking substance is permanent and self-identical. Mind is essentially percipient, and hence permanently existent.

But the permanence of things cannot be so easily preserved. It will not do to say that things are always perceived by finite minds, because that can be experimentally disproved. Berkeley first attempts to maintain the permanence of things by an interesting variety of the Cartesian cogito ergo sum argument. According to this argument, I cannot doubt my own existence, because the very doubt, the thought, proves that a thinker exists. Now Berkeley believes that things exist whenever they are perceived or imagined or thought of. Hence, the very question whether a thing exists proves that it does. As mentioned, it exists.⁵⁶ But Berkeley soon saw that this explanation is untenable. In the first place, the existence of an object merely thought differs from the existence of an object directly perceived. In the second place, what happens to the thing when it is neither perceived nor imagined nor thought on nor referred to in any way? It must simply vanish. But Berkeley could not rest in this conclusion. It is necessary, in order to account for our practical social and moral relations to our fellowmen, that things should exist even when they are not being perceived or referred to in any way. The permanence of things cannot, therefore, depend on our finite minds. It is based on the fact that they exist as powers, or potentially, in the mind of God.⁵⁷ But this is not an actual existence.⁵⁸ Berkeley is thus forced to distinguish two kinds of existence, a permanent potential existence in the mind of God, and an actual intermittent existence only when things are being actually perceived by finite beings. This intermittent existence owes what unity it has to the fact that its potential permanence is guaranteed by God.

Even here Berkeley was influenced by Locke. It is true that God in Berkeley's system is much more important than in Locke's, but the function which Berkeley makes God perform is suggested by Locke. When pressed, Locke is unable to explain how we come to have ideas. In the last resort, he thinks, God is responsible for the regularity and uniformity of our experience. “I see or perceive or have ideas when it pleases God that I should, but in a way that I cannot comprehend.” In imagination I can bring ideas before my own mind by my own volition, but not in perception. The regularity of my perceptual experience depends partly on God, and partly on the material supports of ideas. As Berkeley eliminates material substance, God is left to sustain the whole burden of securing the permanence and identity of things and the regularity of perceptual experience. Berkeley agrees with Locke that while perceptual experience must ultimately be referred to God as its ground, we are the causes both of our imaginative and volitional experience.

Berkeley believes, as we have seen, that minds are necessary for the constitution of experience. But so far we have not yet considered how minds may be known. Minds for Berkeley are sharply distinguished from ideas, and therefore we can have no perceptual or imaginative knowledge of minds. How then do we know minds? On this problem also Berkeley's efforts to reach a solution show the influence of Locke. Locke maintained that knowledge of the mind is possible. If we regard the mind as a tabula rasa, then the knowledge we have of it is intuitive. On the other hand, if we take the mind to be a spiritual substance, then we can have of it precisely the same sort of knowledge as of any other complex idea. Mind, as a spiritual substance, knows itself, as a spiritual substance. Thus a complex idea knows itself. The difficulty of this view is obvious. A complex idea, like the simple ideas of which it is compounded, is passive. How then is it able actively to compound itself? It must be active to bring together the complex of ideas which constitute it. But in its nature it is passive.

In the Commonplace Book Berkeley tried to make use of both of Locke's explanations, but he felt that neither of these views was really satisfactory. Both of them are inconsistent with his doctrine that all our knowledge is derived from the senses. Ex hypothesi, intuitive knowledge is neither sense-knowledge itself, nor derived from sense-knowledge. It is a unique and peculiar sort of knowledge, of which we can give no account. For Berkeley it was a scandalous exception to his doctrine, and one which he was anxious to remove. On the other hand, the view that an idea of the self is possible conflicts equally with Berkeley's theory that all knowledge is perceptual. Berkeley's introspection revealed to him only aggregates of ideas in perpetual flux. Introspection does not enable us to form an idea of the mind as an entity distinct from the series of fleeting perceptions. It is impossible to perceive the mind. Must we then conclude that the mind is utterly unknowable?

Hume, arguing in precisely the same way as Berkeley, that no idea of the mind is possible, took the further steps of affirming that the self is therefore unknowable, and that because it is unknowable it is non-existent. We have seen that Berkeley was unable to rest in the sceptical denial of the permanence of the self. Equally did he avoid scepticism with regard to the knowability of the self. He saw the need of revising his doctrine that all knowledge is knowledge of ideas. Nor was he willing to take refuge in intuition. When the entities of which it was necessary to postulate an intuitive knowledge were only one or two, e.g. the self and God, such important exceptions to the general doctrine that all knowledge is sense-perception might perhaps be allowed. But as soon as it became clear to Berkeley that it would be necessary to admit an intuitive knowledge of whole classes of things, e.g. volitions and other mental operations, he realised that it would be essential to modify his early theory of knowledge.⁵⁹ Knowledge, be believed, is perceptual; but it cannot all be perceptual. There must be another kind of knowledge of such things as selves, volitions, mental operations, and relations. Now Berkeley refused to be content with the obscurum per obscurius of referring such knowledge to intuition. What kind of knowledge is it, then, that we have of such objects? In the Commonplace Book Berkeley has no answer to this question, though he is convinced that (a) we can have no idea of them, and (b) we can know them somehow.

Of what nature this non-ideal knowledge would be Berkeley does not make clear. But he suggests that it would be by way of “pure intellect,” for in such knowledge the mind is active and thoughts called “the interior operations of the mind.”⁶⁰ And Berkeley once or twice speaks of the mind “considering” things, in distinction from perceiving or imagining them. Such entries as these, vague as they are, suggest that even in the days of the Commonplace Book he was engaged on the problem of the nature of what he afterwards came to call “notions.” With this notional knowledge of selves, mental operations, and moral conceptions he intended to deal in Part II. of the Principles.⁶¹

So far, we have been dealing with the implications of what Locke called the complex idea of substance. But substance was not the only kind of complex idea mentioned by Locke. He assumed the existence of two other types of complex idea, which he called respectively modes and relations. Now, modes and relations stand on a very different footing from substances. Substance is not only self-subsisting, it also serves as the support of all qualities. But modes and relations cannot subsist of themselves. Modes depend upon substances, or are attributes of substances; and relations, depending on the comparison of one idea with another, have no existence apart from the ideas which they join, or on which they terminate. Hence modes and relations can never be independent. They cannot exist by themselves: they exist only as dependent upon substances.

On the whole, Berkeley paid very little attention to Locke's doctrine of modes and relations, but even here certain lines of influence may be traced.

With regard to modes Berkeley differs in an important respect from Locke. For Locke all modes are complex ideas, which the mind has made “by combining several simple ideas into one compound one.”⁶² With this definition Berkeley refuses to agree, for in his view a complex idea is not a compound, not one idea, but simply an aggregate of several simple ideas, and, though we may express this aggregate by a single word, no idea corresponds to it. Again, Berkeley holds, modes cannot depend upon, or be affections of, material substance, for it is non-existent. He agrees with Locke that modes are not self-subsisting: “they are not so much existences as manners of the existence of persons.”⁶³ He thus substitutes spirit for material substance as the support of modes. He takes little notice of Locke's distinction between simple and mixed modes. The distinction depends on whether the simple constituents are of similar or different sorts. If the mode is simply the repetition of the same simple idea, as a score, for instance, is a repetition of unity, then the mode is simple; but if the simple ideas compounded to make the complex one are of different sorts, e.g. as beauty involves different ideas of colour, shape, and so on, the mode is mixed. In the Commonplace Book he uses Locke's terminology, but for him the distinction is strictly unmeaning. If a complex idea is merely a bare aggregate (and this, as we have seen, is the only meaning Berkeley is willing to assign to it), it does not matter whether that aggregate is a collection of similar or different ideas.

Of relations, the second of Locke's types of complex ideas which we are at present considering, Berkeley has little to say. He agrees with Locke, as we have seen, that relations exist; but he holds that we can have no idea of them. We can use relations, talk about them, and express them in language by particles. They have a meaning, and that is all we can say of them.

In connection with one particular type of relation, however, Berkeley paid a good deal of attention to Locke's theory. The relation in question is the causal relation. Locke had confused his treatment of the problem by introducing an artificial distinction between the relation of cause and effect and the mode of power. But Berkeley has no artificial schema to support, and he holds that the problems of power and causality are essentially the same. In the Commonplace Book, we may remind ourselves, his world consists of (i) God, (ii) finite selves, and (iii) ideas. He first states that no idea can be a cause, for all ideas are passive. So far he agrees with Locke,⁶⁴ who maintained that God and spirits manifest active power, while things (i.e. Berkeley's ideas) are passive powers. Idea-things for Berkeley as for Locke are susceptible but not productive of change. Thus, for Berkeley as for Locke only God and selves are active; and they alone can strictly be called causes.⁶⁵ At one time Berkeley thought of allowing causality to idea-things, while carefully distinguishing this physical causality from spiritual or true causality.⁶⁶ But later on he deemed it better to restrict causality to spiritual causes alone, and to term idea-things “occasions.” An idea-thing may be the occasion of an action or thought, but it cannot really be the cause.⁶⁷

The problem next arises how to apportion causality between the self and God. In the Commonplace Book Berkeley vacillates, at one time tending to the extreme theory of Malebranche that God is the sole cause, at another to the common-sense belief that finite selves exercise a real causality. On the whole, his view in the Commonplace Book is that God is the ultimate cause of all things, but the proximate cause only of immediate perceptions. Finite selves are the proximate causes of imaginative and volitional experience.

So far, in considering Berkeley's relation to Locke, we have not adverted to the aspect of Locke's theory which, more than any other, led Berkeley to devote himself to the task of refuting him. This was Locke's scepticism.

That Berkeley was hostile to the deists has already been pointed out. Now, the deists themselves regarded Locke as the father of their scepticism, and though Locke went out of his way to disclaim the paternity, Berkeley seems to have been inclined to impute it to him. At any rate, he felt it necessary, in his practical efforts to stamp out “atheism,” to aim straight at what he considered the sceptical tendencies of Locke's theory of knowledge; and his arguments to prove Locke a sceptic are quite ingenious. He shows that, on Locke's own theory, he cannot possibly escape absolute scepticism.

Locke divided knowledge into three kinds which he called respectively intuitive, demonstrative, and sensitive. He believed that only in intuition and demonstration is certainty possible, for only there do we have “real knowledge.” Of all the kinds of knowledge intuition is, Locke affirms, the most certain. By it we perceive the agreement or disagreement of two ideas immediately, without any process of reasoning or inference; e.g. “that white is not black, that a circle is not a triangle, that three are more than two and equal to one and two.”⁶⁸ Demonstrative knowledge, on the other hand, is not immediate; it is always mediated by other ideas, and depends on processes of reasoning which we call proofs. Demonstrative knowledge depends for its certainty on the possibility of proving relations between abstract ideas.

All other so-called knowledge, Locke maintained, is not really knowledge at all, but only opinion. For all knowledge not based on intuition and demonstration is, in the last resort, sensitive knowledge, and thus can give no certainty. For in mere sense-perception we are confined within the limits of our own ideas, and can never reach reality.

For the purposes of criticism Berkeley accepts this classification of knowledge; and argues that, as it can be shown that the first two kinds of knowledge do not give certainty, and as Locke himself admits that the third does not, he cannot escape absolute scepticism.

Berkeley reminds us that demonstrative knowledge for Locke depends on proving relations of agreement and disagreement by means of abstract ideas. Now, Berkeley has already shown that such a conception of abstract ideas as is cherished by Locke is self-contradictory, and it therefore follows, he holds, that the vaunted certainty of his demonstrative knowledge will vanish.

Thus, as Locke himself admits that sensitive knowledge supplies no certainty, and as demonstrative knowledge (at least on Locke's view of it) has been shown to be impossible, it follows that only intuition remains to save him from utter scepticism.

But intuitive knowledge, Berkeley maintains, is only a broken reed; and so far is it from being able of itself to bear our weight that unless we can bring support to it from other quarters we are not justified in ascribing any certainty at all to it. We often think we have an intuitive certainty of what is either unreal or non-existent. Again, what seems intuitively true to one man may seem intuitively false to another, and, if our only standard of certainty is intuition, it will be impossible to decide which of these conflicting intuitions really gives truth. Thus, here also, Berkeley urges, Locke is necessarily involved in scepticism.

Berkeley's own theory of knowledge is, of course, largely modelled on Locke's; but he believes that the changes which he has introduced enable him to escape the force of the criticisms which he has just brought against Locke. Intuitive knowledge he wisely avoids as much as possible, for he sees that the criticisms he has used against Locke's theory are valid against any theory of intuition. Therefore he sets no store by it.⁶⁹ But he believes that certainty is possible on the theories of sensitive and demonstrative knowledge which he developed.

He claims, in the first place, that knowledge in sense-perception is not mere opinion, as Locke held, but gives absolute certainty. “Certainly,” he says, “I cannot err in matter of simple perception.”⁷⁰ “We must with the mob place certainty in the senses.”⁷¹ “Certainty, real certainty, is of sensible ideas.” And though Berkeley came later to modify his belief that error is impossible in sensitive knowledge, he never resiled from the conviction that, in general, the senses provide us with certain knowledge; and he always regarded it as a great part of his work to have vindicated the senses from the aspersions cast upon them by Locke and others.

And certain knowledge is possible also in demonstration. But by demonstration Berkeley does not mean, as Locke did, reasoning by means of intervening abstract ideas; he means reasoning by means of words or signs. “Demonstration,” he says, “can be only verbal.”⁷² In the Commonplace Book Berkeley has simply adopted the extreme nominalism of Hobbes. The possibility of reasoning depends on the demonstration of words. In reasoning about particular things we take one particular to stand for or represent other particulars of the same kind, and to designate the whole class of particulars we use one word. We pay no attention to the differences between the particulars: they bear one name, and it is on the name that we reason. In the Commonplace Book Berkeley simply substitutes words for Locke's abstract ideas. And the reason he gives for the demonstrability of words or signs is precisely that which Locke finds to be responsible for the possibility of demonstrating relations of abstract ideas, i.e. that they are made by us.⁷³ Berkeley changes Locke's conceptualism into a nominalism. But this was a passing phase which was under eclipse by the time he wrote the Principles.

Berkeley's general conclusion in the Commonplace Book is that his theory of knowledge is free from the sceptical tendencies which Stillingfleet and others had discerned in Locke; and that, in spite of its paradoxical appearance, it is the only theory of knowledge perfectly consistent with common sense.

Before passing from our investigation of Berkeley's relation to Locke, we may note (the point is interesting and may be important) that his criticisms of Locke, on several fundamental points, are very similar to those of the latter's little-known critic, John Sergeant. It would be very rash to say that Berkeley adopted them from Sergeant. There can be little doubt that he arrived at them independently. But it is well to bear in mind that, as is shown by a reference in the Commonplace Book,⁷⁴ he was acquainted with Sergeant's Solid Philosophy, and further, not only were many of his most telling criticisms of Locke anticipated in that book, but his own conception of a mind-dependent universe was very clearly foreshadowed by its author.

Though Sergeant was a writer of some merit, he is now almost unknown, and as his Solid Philosophy is extremely rare, I shall point out with some care the respects in which his criticism of Locke forestalls Berkeley, and the suggestions which he makes towards the philosophical doctrine which Berkeley afterwards expounded.

Sergeant's book⁷⁵ is a criticism of Locke's “way of ideas.” In it he makes it his aim, he tells us, “to disintricate truth,” which Locke had allowed to become sadly entangled with words and fancies; and thus to establish “solidly,” in opposition to Locke's ideism and scepticism, our real knowledge of the real world. It is rather interesting to notice in passing that just as our contemporary realists seem all to be tending towards phenomenalism, so this “solidist” anticipates the idealism of Berkeley. But in the meantime I wish to draw attention, not to his anticipation of Berkeley's positive work, but to his criticism of Locke.

Sergeant interprets Locke's “ideas,” precisely as Berkeley does, to mean merely copies or images of things; and he argues, on the same lines as Berkeley adopted, that if our knowledge starts with ideas, we must be forever confined within the circle of our own ideas. If, that is, our knowledge begins in ideas which are defined as similitudes, resemblances, pictures, then our knowledge must terminate in ideas. “That only is known,” says Sergeant, “which I have in my knowledge, or in my understanding; for to know what I have not in my knowledge is a contradiction: therefore, if I have only the idea, and not the thing, in my knowledge or understanding, I can only know the idea and not the thing; and, by consequence, I know nothing without me, or nothing in nature.”⁷⁶

Sergeant goes on to show that if ideas are the copies of things, and if truth consists in the agreement of the copy and the thing, then we must know both the copy and the thing. But we have already seen that we know only the copy. Hence Locke's account of truth falls to the ground. Sergeant, then, deserves credit for his acumen in exposing the fallacy of the doctrine of representative perception. “We cannot possibly know at all the things themselves by the ideas, unless we know certainly those ideas are right resemblances of them. But we can never know (by the principles of the Ideists), that their ideas are right resemblances of the things; therefore we cannot possibly know at all the things by their ideas.”⁷⁷ Of this thesis Sergeant proceeds to give a syllogistic proof. “The minor is proved thus; we cannot know any idea to be a right resemblance of a thing, (nor, indeed, that anything whatever resembles another rightly,) unless they be both of them in our comparing power, that is, in our understanding or reason, and there viewed and compared together, that we may see whether the one does rightly resemble the other, or no. But this necessitates that the thing itself, as well as the idea, must be in the understanding, which is directly contrary to their principles; therefore, by the principles of the Ideists, we cannot possibly know that their ideas are right resemblances of the thing.”⁷⁸

Sergeant also argues that Locke's theory involves a regress ad infinitum. “Again, since Mr. Locke affirms that we know nothing, either by direct or reflex knowledges, but by having ideas of it; it must follow, that when by a reflex act I know my first idea got by a direct impression, I must have an idea of that direct idea, and another idea, when I know that reflex one, of it; and still another of that; and so still on. …”⁷⁹ What seems to impress Sergeant most is the impossibility of an idea of an idea, in the sense of an image, a similitude of a similitude. In this, in itself, there is in reality no difficulty, and his argument is of little value. He is on surer ground when he points out that in the regress of ideas we reach no end: if, that is, we cannot know a thing directly and immediately, but only by means of an intervening idea, then we need another idea to intervene and relate the mind to the original intervening idea. This regress in infinitum is the direct result of the initial assumption of Locke, viz. that we cannot have immediate knowledge of particular things.

Another of Berkeley's criticisms of Locke which is anticipated by Sergeant concerns abstract ideas. Like Berkeley, he argues that abstract general ideas are self-contradictory, because idea for Locke means image or likeness, and an abstract universal image or likeness is a contradiction in terms. Images, like the things of which they are copies, are always particular. “If then we have an idea or likeness of universality, or generality, what is it like? It must either be like the thing, or must be like nothing, and so is no idea or likeness at all. But it cannot be like the thing in any respect, because in the thing there is nothing that is general or universal; but all that there is particular and determined; which is quite unlike, nay, opposite to universality or generality.”⁸⁰

Sergeant then states sharply the dilemma with which Locke and his supporters are confronted. “Philosophy,” he presumes, “is the knowledge of things; but if I have nothing but the ideas of things in my mind, I can have knowledge of nothing but of those ideas. Wherefore, either those ideas are the things themselves, … or else they are not the things, and then we do not know the things at all.”⁸¹ Now, the latter alternative can be shown to lead, as Sergeant points out, to absolute scepticism. He confirms this, at length, by his criticism of Locke's view of the intervention of ideas between the mind and the thing; and concludes, “Wherefore Mr. Locke in pursuance of his own principles should not have said that ‘the mind does not know things immediately, but by means of the ideas’; but that it does not know them at all, neither mediately nor immediately.”⁸²

Thus our general conclusion from the dilemma is that if knowledge is to be saved, the former alternative must be accepted. And it can be proved, Sergeant believes, that the “ideal theory” of Locke logically results in the adoption of the former alternative, i.e. that the ideas are the things themselves. It is necessary for the “ideal theory,” he argues, to identify “idea” and “thing.” “Being thus at a loss to explicate ‘intervention’ or to know what it, or the idea or representative serves for, we will reflect next upon the word ‘know’ which Mr. Locke applies (tho' not so immediately, yet) indifferently, to the thing and to the idea. Now, if this be so, and that to be known agrees to them both; then, as the idea is in the mind when it is known, so the thing, when known, should be in the mind too, which is our very position, thought by the ideists so paradoxical, and yet here forcibly admitted by themselves.”⁸³

All this is, of course, very closely akin to the process of argument by which Berkeley reaches the New Principle, and more than once Sergeant almost stumbles upon Berkeley's actual formulation of it.⁸⁴ It is noteworthy also that the term “notion” which later came to play an important part in Berkeley's philosophy is very prominent indeed in Sergeant's Solid Philosophy.⁸⁵ Whether in any of these points Berkeley directly derived anything from Sergeant must remain a matter of opinion; but, whatever be our judgment, we may at least agree that the striking similarities between them bear a remarkable testimony to the existence at the time of an atmosphere of opposition to Locke in which the development of such a theory as Berkeley's is only what might have been expected.

When compared with the influence exerted upon Berkeley by Locke and this atmosphere of reaction against him, the influence of other thinkers is so slight as to be almost negligible. Almost, but not quite; and, before bringing our account of the origin and early development of Berkeley's thought to a close, we must indicate briefly his relation to the Cartesians, and to the mathematics of the day.

Notes

1. Commonplace Book, i. 38. (All references are to the Oxford Edition of Berkeley's works in 4 vols. 1901.)

2. Ibid, i. 38.

3. Cf. Lechler: Geschichte des Englischen Deismus, p. 195.

4. Peter Browne, with whom Berkeley subsequently had a controversy, was the author of The Procedure and Limits of Human Understanding, and The Divine Analogy.

5. A Letter in Answer to a Book Entitled Christianity Not Mysterious, 1697.

6. Molyneux, the friend of Locke, criticised Browne on this score. (Locke's Works, viii. 428.)

7. “A sermon against his errors was as much expected as if it had been prescribed in the rubric; and an Irish peer gave it as a reason why he had ceased to attend church that once he heard something there about his saviour Jesus Christ, but now all the discourse was about one John Toland.” (Hunt, Religious Thought in England, ii. 244.)

8. For a detailed account of Berkeley's attitude to the deists vide infra, chapter vii.

9. The reasons for this conjecture are as follows. Berkeley, we know, was far ahead of his fellow-students (Life and Letters of Berkeley, p. 23), and it is therefore a priori natural to suppose that he was the first president of the society. Further, the statutes, which deal mainly with elaborate rules of procedure, are written out in full in his book, but not in his handwriting. They are written, no doubt by the secretary, in the president's book for his guidance in directing the discussions. Again, the date of the foundation of the society is January 10, 1705/6, and there is in existence a manuscript of Berkeley's—the Description of the Cave of Dunmore—bearing the same date, which was almost certainly read by Berkeley at the first meeting of the society. (See Hermathena, vol. xi. p. 181.) And it seems probable that the inaugural paper would be read by the president.

   That Samuel Molyneux was secretary is suggested by the fact that the manuscript just referred to and the manuscript of Berkeley's essay Of Infinites (which was apparently read to the same society) were discovered among the Molyneux papers in the library of Trinity College, Dublin, and both bear an endorsement in the writing of Samuel Molyneux (Hermathena, xi. 181). Now it was one of the statutes of the society “that the secretary have the charge of all papers belonging to the society.” (Life and Letters, p. 24.)

10. Life and Letters of Berkeley, p. 25.

11. Ibid. p. 26.

12. Life and Letters of Berkeley, p. 25.

13. Ibid. p. 26.

14. My account of the development of Berkeley's early thought as revealed in the Commonplace Book is based on the supposition that the order in which Berkeley actually made the entries is not that which is adopted by Campbell Fraser in the Oxford edition, but is as follows.

    I. The Statutes of January 1705/6, the queries, and the Statutes of December 1706. (Though these are all in the manuscript of the “Commonplace Book,” they are not printed by Fraser in the Commonplace Book, but are inserted by him in his Life and Letters of Berkeley, pp. 23-27.)

    II. Commonplace Book, pp. 58-89.

    III. Commonplace Book, pp. 7-58.

    IV. Commonplace Book, pp. 89-92.

    (These references are to the “Commonplace Book” as printed by Fraser in the 1901 edition of the Works.)

    It is necessary now to give reasons for adopting this order.

    The essential question relates to the order of the two sections numbered above II. and III. And it may at the outset be pointed out that section I. coheres closely with section II., and is to be regarded as prefatory to it. Section I., which was extracted from its proper place in the “Commonplace Book” by Campbell Fraser for biographical purposes when he published the 1871 edition of the Works, and was apparently overlooked altogether when he brought out the edition of 1901, stands written in the manuscript volume which we call the “Commonplace Book” between the quotation from Clov (?) and the sentence “One eternity greater than another of the same kind.” The quotation from Clov (?) ends one page. Then follow three blank pages. Then we have the statutes of January 1705/6, and the other items which constitute what I have called section I. The sentence “One eternity greater than another of the same kind” runs on immediately after the last of the statutes of December 1706. It is clear, then, that the statutes and queries are connected with section II., and are disconnected from section III., from which they are separated by the three blank pages. That is, section I. is connected with II., but not with III. It is, as we have said, prefatory to II.

    Having now made clear the close connection of I. with II. (which nobody doubts), we proceed to the crux of the question, viz. the transposition of sections II. and III.

    The order in which the Commonplace Book is printed by Campbell Fraser is that of the manuscript volume. The only alterations which Fraser made in editing the manuscript were (a) the excision of section I. (to which we have already alluded), (b) the omission of a few repetitions, and (c) the addition on p. 92 of a few remarks taken from another manuscript of Berkeley. Apart from these intentional interferences with the text of the manuscript, and some errors in deciphering Berkeley's handwriting, the Commonplace Book printed by Campbell Fraser is identical with the manuscript volume.

    Now, as Lorenz was the first to point out (Archiv für Geschichte der Philosophie, xviii. 554), the manuscript volume consists of two notebooks, bound together. Evidence of the former bindings remains, and there is a slight difference in the texture and quality of the paper. One notebook comprises pp. 7-58 down to and including the quotation from Clov (?), i.e. what we have called section III. For convenience we will call this notebook A. The other contains the statutes and queries followed by pp. 58-92, i.e. what we have called sections I., II. and IV. Let us call this notebook B.

    It was suggested by Lorenz that these notebooks had accidentally been bound together in the wrong order. This supposition I have adopted. To substantiate it, it is necessary to show that notebook A must be later than notebook B.

    (1) A contains the date August 28th, 1708. B contains the dates January 10, 1705/6, and December 7, 1706. There is no doubt as to these dates, consequently A must be later than B. This is absolutely conclusive. (There is an entry on p. 84 which might be taken to suggest that it had been written before April 16, 1705. It refers to “Mr. Newton,” and as Newton was knighted on April 16, 1705, the entry, Fraser suggests, would seem to indicate that it was written before that date. This is not, of course, conclusive. It is quite possible that Berkeley simply wrote “Mr. Newton” inadvertently. If Fraser's supposition be true, it still further confirms our contention that B is earlier than A, though it gives rise to difficulties of its own in connection with the statutes, which would then, though preceding the Newton entry in the manuscript, be subsequent to it in time. And this, I think, is a further objection to Fraser's suggestion.)

    (2) That B was written as early as 1706, and therefore before A, is confirmed by the discovery made by Prof. S. P. Johnston of an essay by Berkeley entitled “Of Infinites.” On external and internal evidence Prof. Johnston assigns this essay to the period 1706-7 (Hermathena, vol. xi. pp. 181-2), and a comparison of it with the Commonplace Book shows that it was certainly written at the same time as pp. 83-88.

    (3) Berkeley tells us (Works, ii. 19) that one of his earliest enquiries was about time. Now the only group of entries in the Commonplace Book concerning time is that on pp. 58f. This would be “one of his earliest enquiries” only if B is prior to A.

    (4) But by far the most convincing confirmatory evidence of the priority of B is that supplied by a consideration of the subjects dealt with in the two parts. There are, for instance, two or three fairly certain references from A to B. On p. 12 we have the following: “Motion on 2nd thoughts seems to be a simple idea.” Now, motion has not been mentioned previous to this in A. In B, on the other hand, motion is mentioned in such a way as to imply that it is a complex idea. That is, we have Berkeley's first thought in B, and his second thought in A. Again, in B we frequently find dogmatic and unguarded statements which are carefully qualified in A. For instance, he states in B, absolutely and without qualification, that in perception the mind is essentially passive (p. 83). But in A he qualifies this by adding, “There is somewhat active in most perceptions” (p. 37). Lastly (and this seems to be an irrefragable example), in B he defines “bodies” as “combinations of powers,” obviously a technical definition of his own (p. 64). But in A he reminds himself “not to mention the combinations of powers” (p. 50). Now, the phrase “combinations of powers” has not previously been mentioned in A. The reference is clearly to the passage in B.

    (5) Finally, if we take the Commonplace Book printed in the Oxford edition, it is impossible to trace any development in Berkeley's thought. On the very first page of A, in the second entry, we have a reference in detail to the structure of the Introduction to the Principles, and Berkeley speaks in a most familiar way of the application of the Principle to various difficulties. The first few pages of A show, in fact, that he had already reached the stage of drafting the Principles, and was even paying attention to the phrasing of important passages. In A the references are all to the Principles. On the other hand, B contains almost the whole of the argument of the New Theory of Vision, which was certainly developed before the Principles. And the general style and atmosphere of A are more mature than B. Most important of all, on the supposition that B precedes A in time, it is possible to discern a real continuity of argument and progress of thought. This is shown in the brief exposition of the argument of the Commonplace Book which I have given in the text, and need not be repeated here. The reality of this continuity grows on the mind the more frequently one reads the Commonplace Book; and no one who reads it over several times, first in one order and then in the other, can avoid the conclusion that Berkeley wrote B before A.

    For all these reasons, then, we maintain that the order in which Berkeley actually made his jottings is that which we have adopted. The essential question, let us repeat, concerns our transposition of sections II. and III., and this we have proved to be justified.

    A word or two will suffice for the unimportant question why pages 89-92 are postponed to notebook A, though they really occur at the end of B. In the manuscript there is a hiatus where on p. 89 in the Oxford edition a line is drawn. That is, the portion of p. 89 after the line does not follow on uninterruptedly the part of p. 89 before the line. We thus have this initial reason for separating p. 89 ff. from the rest of B. Now, pp. 89-92 consist of (a) nineteen carefully stated and numbered axiomatic statements of the salient points of Berkeley's New Principle, followed by (b) a few jottings of the usual kind. Now, it may be suggested that what Berkeley did was this. He began by writing notebook B from the beginning to p. 89. He then left a few pages blank at the end of the notebook, in order to state there the positive results of his thought. At the same time he started a new book (A) for the purpose of continuing his jottings and queries. Finally, when A was completely filled (it is filled from the first page to the last), he returned to the pages at the end of B, some of which still remained blank, and wrote the page or two of jottings which form the end of the Commonplace Book. But it should be remembered that this is merely conjecture. And, in any case, nothing of importance in connection with the development of Berkeley's thought depends upon it. On the other hand, what is of vital importance, i.e. the transposition of II. and III., we take to be definitely established.

15. Commonplace Book, i. 58.

16. It is noticeable that in dealing with these points, soon to be expounded in the New Theory of Vision, Berkeley is distinctly more sure of himself than when discussing the problems which we have mentioned in the previous two paragraphs. There he is, for the most part, still asking questions. Here, on the other hand, he makes assertions.

17. i. 27.

18. i. 18.

19. Cf. Introduction to the Principles, § 13, Principles, §§ 8, 10, 22, 24, 25, 27, 45.

20. Introduction to the Principles, § 22.

21. i. 25.

22. Commonplace Book, i. 21. Cf. Locke's Essay, iv. i. 1.

23. Essay, iv. iv. 3.

24. An Examination of Father Malebranche's Opinion of Seeing All Things in God.

25. i. 90.

26. i. 56.

27. i. 63.

28. i. 50.

29. i. 35.

30. i. 47.

31. i. 51.

32. i. 9.

33. Essay, ii. viii. 15.

34. i. 59.

35. i. 23.

36. Essay, ii. xxiii. 2.

37. i. 64.

38. i. 20.

39. i. 60, 61, 64.

40. Essay, ii. vii. 7.

41. At the risk of labouring the obvious, I should like to repeat that the features of Berkeley's theory which excited most attention in his own day on account of their apparently paradoxical character were immediately derived from suggestions made by Locke, though never elaborated by him.

42. Under percipere Berkeley here means to include volitions and other active operations of the mind. In the margin of the Commonplace Book, opposite the entry quoted above, and with reference to the word Percipere, he adds a note, “or velle, i.e. agere.” He hesitates a good deal whether to affirm that the mind is active in perception. On the whole, he seems to incline to the view that (a) in sense-perception the mind is passive and receptive, while (b) in imagination (which he sometimes includes under percipere) the mind is active. But he also maintains, without vacillation, that it is really volition that constitutes the activity of the mind; and, as he believes that volition is impossible apart from perception, the activity of volitional experience confers a certain degree of activity on percipient experience. (Cf. Commonplace Book, i. 34, 37, 47, 52, 83.)

43. In the fourth edition of the Essay, Locke, perceiving the inconsistency into which he was led by this doctrine, introduced a paragraph or two pointing out that in certain cases the mind might exercise active functions. (Essay, ii. xii. 1.)

44. Essay, ii. i. 13.

45. “Locke seems to be mistaken when he says thought is not essential to the mind” (i. 34).

46. Locke left the question open whether spiritual substance is really spiritual or simply very finely material. The latter interpretation of the spiritual was well known in the Schools, and Locke admits the possibility that spiritual substance may really be very fine material substance. This was anathema to Berkeley.

47. i. 27, 28.

48. i. 27, 31, 38, 41, 51, 53, 56, 69.

49. i. 28.

50. i. 41.

51. i. 45. Italics mine.

52. i. 41.

53. i. 72.

54. i. 71.

55. i. 34.

56. i. 15.

57. i. 61.

58. i. 71.

59. i. 24.

60. i. 81.

61. It is quite certain that, when the Commonplace Book was written, Berkeley believed that this non-ideal knowledge is the only kind of acquaintance we can have with the self, the will, and mental operations in general. Of these, he repeatedly states, we can have no idea. (Cf. Commonplace Book, i. 35, 36, 49.)

62. Essay, ii. xii. 1.

63. i. 59.

64. Locke is not quite positive on this point. (Cf. Essay, ii. xxi. 2.)

65. There is, however, another side to Locke's view.

66. i. 55.

67. i. 55.

68. Essay, iv. ii. 1

69. Yet he occasionally uses intuition rashly. (Cf. i. 24, 26.)

70. i. 39.

71. i. 44.

72. i. 50. Italics mine.

73. i. 44.

74. i. 54.

75. Solid Philosophy Asserted, against the Fancies of the Ideists: or, the Method to Science Farther Illustrated. With Reflections on Mr. Locke's Essay concerning Human Understanding. London, 1697.

76. Op. cit. p. 30. Cf. p. 20.

77. Op. cit. p. 31.

78. Op. cit. pp. 31-32. Cf. p. 342.

79. Op. cit. p. 20.

80. Op. cit. Preface, § 24.

81. Op. cit. p. 30.

82. Op. cit. p. 341.

83. Op. cit. pp. 340-341.

84. See, for example, Solid Philosophy, pp. 32 ff. and 339 ff. And for other points at which Sergeant's attitude to Locke is very similar to Berkeley's, see op. cit. p. 265, 318 and 321.

    Berkeley would have done well to take to heart one of Sergeant's criticisms of the use of God by Locke and Descartes. “God was brought in at every hard pinch, to act contrary to what the natures of things required; without which, they could not lay their principles, or make their scheme cohere; that is, they would needs make God, as he is the Author and Orderer of Nature, to work either preternaturally or else supernaturally; which is a plain contradiction.” (Epistle Dedicatory, op. cit.)

85. Berkeley's relation to Sergeant's doctrine of “notions” is considered below, Chap. IV. ii., and see also Appendix II.