Berkeley's Argument for Immaterialism

A. C. Grayling

Berkeley's philosophical view is often described as an argument for "immaterialism", by which is meant a denial of the existence of matter (or more precisely, material substance.) But he also, famously, argued in support of three further theses. He argued for idealism, the thesis that mind constitutes the ultimate reality. He argued that the existence of things consists in their being perceived. And he argued that the mind which is the substance of the world is a single infinite mind – in short, God. These are four different theses, but they are intimately connected in Berkeley's presentation of them, the arguments for the first three sharing most of their premisses and steps. My chief purpose in what follows is to give an account of these arguments, their interactions, and the assumptions and methods underlying them. Doing so makes their strengths and weaknesses both conspicuous and perspicuous.

Berkeley's philosophical aim in arguing for these theses is to refute two kinds of scepticism. One is epistemological scepticism, which says that we cannot know the true nature of things because (familiarly) certain perceptual relativities and psychological contingencies oblige us to distinguish appearance from reality in such a way that knowledge of the latter is at least problematic and at worst impossible. The other is theological scepticism, which Berkeley calls "atheism" and which in his view includes not only views that deny the existence of a deity outright, but also Deism, for which the universe subsists without a deity's continual creative activity. In opposing the first scepticism Berkeley took himself to be defending common sense and eradicating "causes of error and difficulty in the sciences." In opposing the second he took himself to be defending religion.

The attack on theological scepticism is effected on a metaphysical rather than doctrinal level in P and D. Doctrinal questions receive more attention in such later writings as Alciphron. But in one important respect Berkeley saw his views as a fundamental contribution to natural theology, in that he thought they constitute a powerful new proof of the existence of a God.

Berkeley takes the root of scepticism to be the opening of a gap between experience and the world, forced by theories of ideas like Locke's which involve 'supposing a twofold existence of the objects of sense, the one intelligible, or in the mind, the other real and without the mind" (P86). Scepticism arises because "for so long as men thought that real things subsisted without the mind, and that their knowledge was only so far forth real as it was conformable to real things, it follows, they could not be certain they had any real knowledge at all. For how can it be known, that the things which are perceived, are conformable to those which are not perceived, or exist without the mind?" (ibid.) The nub of the problem is that if we are acquainted only with our own perceptions, and never with the things which are supposed to lie beyond them, how can we hope for knowledge of those things, or even be justified in asserting their existence?

Berkeley's predecessors talked of qualities inhering in matter and causing ideas in us which represent or even resemble those qualities. Matter or material substance is a technical concept in metaphysics, denoting a supposed corporeal basis underlying the qualities of things. Berkeley was especially troubled by the un-empiricist character of this view. If we are to be consistent in our empiricist principles, he asked, how can we tolerate the concept of something which by definition is empirically undetectable, lying hidden behind the perceptible qualities of things as their supposed basis or support? If the concept of matter cannot be defended, we must find a different account of experience and knowledge. Berkeley summarises his diagnosis of the source of scepticism, and signals the positive theory he has in response to it, in a pregnant remark in C: "the supposition that things are distinct from Ideas takes away all real Truth, & consequently brings in a Universal Scepticism, since all our knowledge is confin'd barely to our own Ideas" (C606).

A point that requires immediate emphasis is that Berkeley's denial of the existence of matter is not a denial of the existence of the external world and the physical objects it contains, such as tables and chairs, mountains and trees. Nor does Berkeley hold that the world exists only because it is thought of by any one or more finite minds. In one sense of the term "realist", indeed, Berkeley is a realist, in holding that the existence of the physical world is independent of finite minds, individually or collectively. What he argues instead is that its existence is not independent of Mind.

Berkeley's "New Principle"

Berkeley's answer to scepticism, therefore, is to deny that there is a gap between experience and the world–in his and Locke's terminology: between ideas and things–by asserting that things are ideas. The argument is stated with admirable concision in P1-6, its conclusion being the first sentence of P7: "From what has been said, it follows, that there is not any other substance than spirit, or that which perceives". All the rest of P, D, and parts of his later writings, consist in expansion, clarification and defence of this thesis. The argument is as follows.

Berkeley begins in Lockean fashion by offering an inventory: the "objects of human knowledge" are "either ideas actually imprinted on the senses, or such as are perceived by attending to the passions and operations of the mind, or lastly ideas formed by help of memory and imagination, either compounding, dividing, or barely representing those originally perceived in the aforesaid ways". Ideas of sense–colours, shapes, and the rest–are "observed to accompany each other" in certain ways; "collections" of them "come to be marked by one name, and so to be reputed one thing", for example an apple or tree (P1).

Besides these ideas there is "something which knows or perceives them"; this "perceiving, active being is what I call mind, spirit, soul or myself", and it is "entirely distinct" from the ideas it perceives (P2).

It is, says Berkeley, universally allowed that our thoughts, passions, and ideas of imagination do not "exist without the mind". But it is "no less evident that the various sensations or ideas imprinted on the sense, however blended or combined together (that is, whatever objects they compose) cannot exist otherwise than in a mind perceiving them" (P3).

From these claims it follows that the gap between things and ideas vanishes; for if things are collections of qualities, and qualities are sensible ideas, and sensible ideas exist only in mind, then what it is for a thing to exist is for it to be perceived‹in Berkeley's phrase: to be is to be perceived: esse est percipi. "For what is said of the absolute [i.e. mind-independent] existence of unthinking things [i.e. ideas or collections of ideas] without any relation to their being perceived, that seems perfectly unintelligible. Their esse is percipi, nor is it possible that they should have any existence, out of the minds or thinking things which perceive them" (P3).

Berkeley knows that this claim is surprising, so he remarks that although people think that sensible objects like mountains and houses have an "absolute", that is, perception-independent, existence, reflection on the points just made show that this is a contradiction. "For what," he asks, "are the aforementioned objects but the things we perceive by sense, and what do we perceive besides our own ideas or sensations; and is it not plainly repugnant [illogical, contradictory] that any of these or any combination of them should exist unperceived? (P4)

The source of the belief that things can exist apart from perception of them is the doctrine of "abstract ideas", which Berkeley attacks in his Introduction to P. Abstraction consists in separating things which can only be separated in thought but not in reality, for example the colour and the extension of a surface; or which involves noting a feature common to many different things, and attending only to that feature and not its particular instantiations – in this way we arrive at the "abstract idea" of, say, Redness, apart from any particular red object (P Introduction 6-17). Abstraction is a falsifying move; what prompts the "common opinion" about houses and mountains is that we abstract existence from perception, and so come to believe that things can exist unperceived. But because things are ideas, and because ideas only exist if perceived by minds, the notion of "absolute existence without the mind" (i.e. without reference to mind) is a contradiction (P5).

So, says Berkeley, to say that things exist is to say that they are perceived, and therefore "so long as they are not perceived by me, or do not exist in my mind or that of any created spirit, they must either have no existence at all, or else subsist in the mind of some eternal spirit" (P6). And from this the conclusion it follows that "there is not any other substance than spirit, or that which perceives" (P7).

In sum argument is this: the things we encounter in episodes of perceptual experience – apples, stones, trees – are collections of "ideas." Ideas are the immediate objects of awareness. To exist they must be perceived; they cannot exist "without the mind." Therefore mind is the substance of the world.

Berkeley's defence of this argument from P7 onwards reveals the machinery that drives it, consisting of the interplay between three crucial commitments and the application of an analytic method which requires us to recognise three different levels of explanation – whose own interrelations, in turn, are pivotal to his case.

The Machinery of Berkeley's Argument

Let us take the question of the three levels first. Berkeley distinguishes between "strict", "speculative" or "philosophical" ways of understanding matters, and ordinary or "vulgar" ways of doing so. When we "think with the wise" we find it necessary to give explanations at what I shall label "level 1" and "level 3." When we "talk with the vulgar" we do so at "level 2" (see e.g. P34-40, esp. P37; 45-8, 3D234-5, C274).

Level 1 concerns the phenomenology of experience, consisting of the data of sensory awareness in the form of minima of colour, sound, and so for the other senses. Level 2 concerns the phenomena of experience – the tables, trees, and so forth, that we see and touch in the normal course of perception. The phenomenological level (call it level 1) is apparent to us only on a "strict and speculative" examination of experience.

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