Abstract Ideas

Berkeley held that philosophy is in a bad state. In attempting "to follow the light of a superior principle, to reason, meditate, and reflect on the nature of things," we end up

drawn into uncouth paradoxes, difficulties, and inconsistencies, which multiply and grow upon us as we advance in speculation, till at length, having wandered through many intricate mazes, we find ourselves just where we were, or which is worse, sit down in a forlorn skepticism. (Principles, Introduction, Section 1)

Logic and metaphysics have in common a central concern with the use of general terms. There has been an ongoing dispute among philosophers since Plato about what general terms stand for or signify. Realists hold that they signify real entities. The general term "man," for example, stands for an abstract object, humanity, which in some way exists. Nominalists, following William of Ockham, claim that the term stands for nothing more than a conception in the mind that refers to individual things indifferently.

In Locke's empiricist account of the origin of ideas, the semantics of general terms is nominalist in character. We always begin with particular ideas, and then by a process of abstraction we generate general ideas. In abstracting, we separate simple ideas "from all other ideas that accompany them in their real existence" (An Essay Concerning Human Undertanding, Book II, Chapter 12, Section 1).

In Book III, Locke gives the example of a child who forms the general idea of man. He first observes his mother and his nurse, forming particular ideas of them. Then he forms ideas of other things resembling his mother and his nurse, and finally he forms an abstract idea of a human by leaving out whatever features these resembling ideas do not all share in common (Essay, Book III, Chapter 3, Section 7). The general idea of animal is formed in the same way, by noting features shared by a certain class of objects and forming an abstract idea which leaves out the features in which they differ.

Locke thought that his account was superior to the Aristotelian account, because it dispels the "mystery" of the nature of genus and species (Essay, Book III, Chapter 3, Section 9). These Aristotelian notions "make such a noise in the schools and are with justice so little regarded out of them" (Essay, Book III, Chapter 3, Section 9). The mystery is solved by understanding genus and species as themselves being general ideas. As such, they are "only creatures of our own making" (Essay, Book III, Chapter 3, Section 11), whose sole basis is the similarity of things to one another.

Berkeley was not satisfied with Locke's reduction of genus and species to ideas. While he endorsed the basic approach, to substitute general ideas for real universals, he disagreed with the way Locke had understood what a general idea is. Specifically, he claimed that general ideas are not distinct from particular ideas. Locke's mistake was to describe the formation of general ideas by a process of abstraction that generates from particular ideas an abstract idea that leaves out various of their features.

For Berkeley, such separation (or "precision") of the features of particular ideas from one another is impossible. How, he asks, could one form the idea of a man that has no one color, stature, height, etc.? "The idea of man that I frame to myself must be either of a white or a black or a tawny, a straight or a crooked, a tall or a short or a middle-sized man"(Principles, Introduction, Section 10). We do have particular ideas of men, and any one of these ideas may be made general by being used to signify indifferently objects that resemble them (Principles, Introduction, Section 12).

An obvious response to Berkeley's claim is that his is mistaking images for conceptions. Locke could concede the impossibility of framing an image of a man without specific quantitative features. But this does not preclude the framing of an intellectual conception which lacks these features. This is what the rationalists had in mind, especially when they warned that the imagination obscures the clear intellectual perception of things of which the mind is capable.

A Berkeleyan response might be that the only evidence we have for the so-called pure conceptions of the intellect is found in our use of words. We use the word "man" in a general way to refer to all specific human beings. But the word does not denote some further idea. Language leads us to think that legitimate general terms refer to an abstract idea just as particular terms like 'Socrates' refer to concrete objects. But the needs of language can be served by using particular ideas in a general way, say by making the idea of Socrates a representative of all humans.

Against Mind-Independent Bodies

Descartes and Locke had held that bodies are material substances which exist independently of minds (except for being sustained by God). Berkeley advanced many arguments against this thesis. Specifically, he rejects "the absolute existence of unthinking things, without any relation to their being perceived" (Principles, Section 1). We will consider only some of Berkeley's arguments. (Later we shall see that Berkeley allows that there are mind-dependent bodies.)

According to Locke, we have sensitive knowledge of the existence of mind-independent bodies (Book IV, Chapter 11). We know that bodies exist when they operate on us to produce sensible ideas of them. Locke recognizes that the certainty of this knowledge falls short of that of intuitive knowledge, but he thinks this certainty is "not only as great as our frame can attain to, but as our condition needs" (Book IV, Chapter 11, Section 8). Descartes had held that we can be demonstratively certain of the existence of mind-independent bodies and morally certain of particular facts about them. Locke claims that we have at most moral certainty for any belief about the existence of mind-independent bodies.

Locke's general position is that what certainty we have about the existence of mind-independent bodies is based on trust in our faculties. "If we persuade ourselves that our faculties act and inform us right concerning the existence of those objects that affect them, it cannot pass for an ill-grounded confidence" (Book IV, Chapter 11, Section 3). Berkeley's main contention is that our faculties do not "act and inform us" about the existence of mind-independent bodies.

To lay the groundwork for the one type of argument found in the Principles, we return to the ambiguity in the word "idea" as used by Locke. He sometimes used it to refer to what is "in the mind," that which the mind perceives directly and which depends on perception for its very existence. Let us call this usage "idea₁." The second usage of "idea" is to refer to qualities of bodies which produce ideas₁. We shall call this usage 'idea₂.' Locke held that bodies are composed of primary qualities (ideas₂), which are supported by an unknown something which he called "substance in general." It makes perfect sense, then, to say that mind-independent bodies are ideas. We see and feel bodies only by having ideas₁, but unlike ideas₁, ideas₂ exist whether or not they are perceived.

Berkeley contends that the distinction between ideas₁ and ideas₂ cannot be made, and that all ideas are ideas₁. Thus when Locke claims that the senses inform us of the existence of "the things we see and feel," Berkeley responds that the things we see and feel are ideas₁ and nothing more. The ideas₁ of sense are mind-dependent: they would not exist at all if no mind were perceiving them. (Their esse is pericipi.)

The rejection of the distinction between ideas₁ and ideas₂ is based on the claim that it we cannot abstract the existence of a thing from its being perceived. "It is impossible for me to conceive in my thoughts any sensible thing or object distinct from the sensation or perception of it" (Principles, Section 5). This is on the face of it a dubious claim. It might seem that we can distinguish between the capability of an object to be perceived and its actually being perceived. A sensible thing need not be sensed. Berkeley must show that such a distinction cannot be made: if an object can be perceived, it is perceived.

The so-called "master" argument of Section 23 tries to show that it is impossible to conceive of a sensible object which is not actually being perceived. Suppose I try to conceive of an object existing unperceived. If I am successful in conceiving of an object, then my conception is related to that object, and so it is an idea. "When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas" (Principles, Section 23). Since the being of ideas depends on their being perceived, the allegedly unperceived but perceivable object is in fact being perceived whenever we try to think of it. So we cannot separate its existence from its being perceived.

This argument is readily criticized. When Berkeley claims that any conceived object is an idea, why should he be entitled to understand this to mean that any conceived object is an idea₁, the kind of idea which depends on being perceived in order to exist? Locke could admit that in conceiving any unperceived (that is, unsensed) object, we must represent it through an idea₁ which is our conception of it. But representing a thing through an idea₁ does not in and of itself make the thing represented an idea₁.

It seems that the most Berkeley is entitled to claim is that we cannot conceive of any body which stands in no relation at all to being perceived. The body would at least be conceivable, and thus not in every way independent of all minds. But standing in this relation is not a condition of the existence of the object. Even if there were no minds to conceive it, the body would remain conceivable.

Another argument against the existence of mind-independent bodies is based on Locke's treatment of "material substance." If Locke is right, then a mind-independent body is a set of qualities united by a "support" or "substratum." But Locke admits that he has no positive idea of what a "support" or "substatum" might be. It certainly cannot be a support in the literal sense, since physical supports are bodies, and the notion of a support is supposed to explain what a body is (Principles, Section 16). Berkeley concludes that the notion has no meaning at all, in which case we cannot understand how there could even be such a thing as a mind-independent body.

Even granting that it is possible that bodies exist with perceivable qualities, Berkeley argues that we could not know that they exist. Our only evidence of their existence is the ideas₁ that we have through sensation. From this evidence we would have to infer that the cause of these ideas₁ is bodies acting on us.

But this inference has nothing to recommend it (Principles, Section 19). In the first place, it is not necessary to invoke mind-independent bodies to explain the existence of our ideas₁, since they exist in dreams, hallucinations, etc. without being caused by bodies that resemble them. Thus, we can at best conclude from the evidence that it is probable that the bodies exist.

Here Berkeley exploits a weakness in his opponents' position. No "materialist" is able to explain how it is that the action of bodies on our minds produces an idea. "They admit themselves unable to comprehend in what manner body can act upon spirit or how it is possible it should imprint any idea on the mind" (Principles, Section 19). Locke, for example, eschews the consideration of how ideas of sensation are produced (Essay, Book I, Chapter 1, Section 2).

If there is no adequate account of how one thing is supposed to cause another, then the claim that the first actually does cause the second is weakened. So, there is no compelling reason to invoke bodies as the cause of our ideas₁, as opposed to saying that they have some other cause. (This kind of argument was made by Malebranche, who nonetheless admitted that mind-independent bodies exist.)

Spirits

All our ideas are mind-dependent, according to Berkeley, and we cannot conceive of anything existing independently of a mind. Thus Berkeley's ontology contains two kinds of beings, ideas and minds (or "spirits"). He recognizes his own mind as what perceives his ideas, but this does not guarantee that there are any other spirits. Like Descartes, Berkeley concluded that he is not responsible for the production of many of his ideas. The are impressed upon him without his willing that they exist. To explain the production of these ideas, Berkeley turned to another spirit, God. He did not postulate a lesser spirit as the cause of is ideas because he thought that the extent, order, grandeur of the ideas impressed on him could only be the work of an infinite spirit.

Phenomenalism

If there is no mind-independent matter, and only ideas and spirits exist, it seems to follow that there are no physical objects or bodies. But this would follow only if bodies must be mind-independent. This Berkeley denied. On his view, a body is a collection of ideas, i.e., that of a particular extension, figure, texture, color, etc. This view has come to be known as "idealism" or "phenomenalism." Bodies are distinguished from merely imagined objects because the collection of ideas coheres with other collections of ideas. Berkeley thus adopted the Cartesian criterion for distinguishing waking experience from dreams, with the difference that all that is perceived in waking experience is collections of ideas.

This view raises a host of problems, which Berkeley tried to address in considering a number of objections in the Principles of Human Knowledge and in the later Three Dialogues between Hylas and Philonous. The most obvious problem concerns the existence of bodies that are not presently perceived. It would seem that the collection of ideas making up an object vanishes when one turns one's attention to another collection of ideas. How could the body continue to exist?

Berkeley had two answers to this question. The first answer is that to say the body persists is to say that if he were to change the focus of his attention, he would have the requisite collection of ideas. But we might then ask why this is so. The second and more fundamental answer is that the ideas of body are produced by God, and that God produces the correct ideas when needed. So if I turn my attention away from the desk, then turn it back, God will be sure to supply an appropriate collection of ideas. If a book was taken from the desk in the interim, I would not have a collection of ideas that constitutes the book.

Common Sense

This elaborate metaphysical scheme seems to fly in the face of common sense. Samuel Johnson once kicked a rock and declared that he had thereby refuted Berkeley. Others have objected that since one's body is a collection of ideas, there would be no harm in jumping off a cliff. Neither of these objections is at all successful, however. The human body is a collection of ideas, on Berkeley's view, as is the rock. The act of kicking the rock takes place entirely in the realm of ideas. Even if rocks did exist independently of minds, our perception of a rock being kicked would itself consist of nothing but ideas. And if we abuse our bodies, the result would be new collections of ideas, which would include plenty of pains.

In point of fact, Berkeley noted, the uneducated or "the vulgar" have no view at all about whether or not bodies depend on the mind for their existence. If you were to ask an uneducated person whether a particular rock exists, the response would be "Yes, I see and feel it," or "No, I don't see it or feel it." The answer, that is, would be given by reference to what philosophers call "ideas." The philosopher would tell a more elaborate story, involving God's production of ideas in our minds. But the two are compatible so long as the philosopher will "think with the learned and speak with the vulgar" (Principles, Section 51).

In fact, the vulgar speak more truly than philosophers like Locke and Descartes in another respect. A peasant might say that a particular tulip is red. If you were to ask whether the red is in the tulip just as he sees it, he would answer yes (if he understood the question). Locke had held, on the contrary, that there is no resemblance between the perceived red and the power in the tulip that produced the idea (Essay, Book II, Chapter 8, Section 15). Berkeley sides with the common sense of the peasant. All the qualities we perceive as in bodies are really in them, since qualities are ideas and bodies are just collections of perceived ideas. There is no story of how some qualities have powers to produce ideas that do not resemble them, because qualities have no powers at all. Only spirits are able to produce anything. Ideas are perfectly inert.

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