George Berkeley’s (1685–1753) philosophy of subjective idealism (which he called “immaterialism”) has two bold and fundamental assertions about reality:
Proposition (1): that the only things that exist are (i) minds and (ii) objects of perception (ideas), andIt follows from this that the external world of matter we normally think exists does not exist, under Berkeley’s ontology.
Proposition (2): the objects of perception only exist at the same time when they are perceived by a mind (Stoneham 2009: 119).
I think any non-dogmatic realist would accept that it is possible that these propositions might be true. Also, I doubt whether any idealist can prove such propositions with necessary or apodictic truth. Also, I assume that a non-dogmatic idealist would also admit that it is possible that the realist position might be true.
Realists and materialists who reject Berkeley’s idealism come in two main groups:
(1) indirect or representative realists (and modern scientific realists), andDirect realists would argue that actual physical objects in the external world are amongst the “objects of perception,” whereas the indirect realists argue that physical objects in the external world are not amongst Berkeley’s “objects of perception.”
(2) direct realists. (Stoneham 2009: 120–121).
Thus it is possible for an indirect realist to accept Berkeley’s proposition (2) above, but reject as untrue proposition (1) above.
On realism, I take position (1): the indirect or representative realist view. This states that it is highly probable that there is an external physical world of objects or things/events that corresponds indirectly to some objects of perception in the sense that some objects of perception are causally dependent on real objects.
But we do not have direct access to the external objects of reality, but only to some conscious “objects of perception” that are causally dependent on them. That is to say, the objects and events of the world of matter and energy described by science are not objects of immediate experience/“objects of perception”.
So the indirect realist/materialist’s inductive argument does not say that the external object and the internal “objects of perception” are absolutely equivalent (as noted in Stoneham 2009: 121).
The human mind’s “objects of perception” are representations (with colour sensations, shapes and so on) of sense data from the external world such as, for example, from the swarm of particles called a tree, and this system of internal representation is the product of Darwinian evolution, and one could conceive of a mind capable of representing the same tree in different ways from different data beyond the visible spectrum (e.g., infrared or x-rays).
Furthermore, the actual qualities we perceive in our minds like green and red are not qualities of the actual object existing in material reality, but are merely causally dependent on them to some extent (e.g., light waves reflected off the object are the causal factor for perception of colours).
So we see that the indirect realist makes a crucial distinction between (1) “objects of perception” and (2) external objects that we do not experience directly. Our argument for the existence of an external world of events/objects is an inductive one based on empirical evidence. Its truth is at most very probable, not certain.
But to return to Berkeley’s arguments, as Stoneham (2009: 121) notes, Berkeley has a great many arguments for his two fundamental positions, such as
(1) the argument that there is no serious difference between primary qualities (such as size, motion and shape) and secondary qualities (colour, taste and texture), against Locke’s claim that primary qualities inhere in the external objects we perceive, andThese major arguments are presented in The Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713).
(2) the so-called “master argument”;
I intend below to focus on what has come to be called Berkeley’s “master argument” (coined by Gallois 1974) because Berkeley intended it to be a crucial argument in support of his idealism.
I. The Master Argument
First, let us look at the master argument as written in The Principles of Human Knowledge (1710):
“22. …. Insomuch that I am content to put the whole upon this issue – if you can but conceive it possible for one extended moveable substance, or, in general, for any one idea, or anything like an idea, to exist otherwise than in a mind perceiving it, I shall readily give up the cause. And, as for all that compages of external bodies you contend for, I shall grant you its existence, though you cannot either give me any reason why you believe it exists, or assign any use to it when it is supposed to exist I say, the bare possibility of your opinions being true shall pass for an argument that it is so.Next, the master argument in Three Dialogues between Hylas and Philonous (1713). In this philosophical dialogue, Philonous is Berkeley’s mouthpiece:
23. But, say you, surely there is nothing easier than for me to imagine trees, for instance, in a park, or books existing in a closet, and nobody by to perceive them. I answer, you may so, there is no difficulty in it; but what is all this, I beseech you, more than framing in your mind certain ideas which you call books and trees, and at the same time omitting to frame the idea of any one that may perceive them? But do not you yourself perceive or think of them all the while? This therefore is nothing to the purpose it only shews you have the power of imagining or forming ideas in your mind; but it does not shew that you can conceive it possible the objects of your thought may exist without the mind. To make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest repugnancy. When we do our utmost to conceive the existence of external bodies, we are all the while only contemplating our own ideas. But the mind, taking no notice of itself, is deluded to think it can and does conceive bodies existing unthought of or without the mind, though at the same time they are apprehended by or exist in itself. A little attention will discover to any one the truth and evidence of what is here said, and make it unnecessary to insist on any other proofs against the existence of material substance.” (The Principles of Human Knowledge §21–22).
“Philonous: Either, Hylas, you are jesting, or have a very bad memory. Though indeed we went through all the qualities by name one after another, yet my arguments or rather your concessions, nowhere tended to prove that the Secondary Qualities did not subsist each alone by itself; but, that they were not at all without the mind. Indeed, in treating of figure and motion we concluded they could not exist without the mind, because it was impossible even in thought to separate them from all secondary qualities, so as to conceive them existing by themselves. But then this was not the only argument made use of upon that occasion. But (to pass by all that hath been hitherto said, and reckon it for nothing, if you will have it so) I am content to put the whole upon this issue. If you can conceive it possible for any mixture or combination of qualities, or any sensible object whatever, to exist without the mind, then I will grant it actually to be so.It seems clear that Berkeley thinks of “sensible objects” or “ideas” as the objects of perception (Stoneham 2009: 119).
Hylas: If it comes to that the point will soon be decided. What more easy than to conceive a tree or house existing by itself, independent of, and unperceived by, any mind whatsoever? I do at this present time conceive them existing after that manner.
Philonous: How say you, Hylas, can you see a thing which is at the same time unseen?
Hylas: No, that were a contradiction.
Philonous: Is it not as great a contradiction to talk of conceiving a thing which is unconceived?
Hylas: It is.
Philonous: The tree or house therefore which you think of is conceived by you?
Hylas: How should it be otherwise?
Philonous: And what is conceived is surely in the mind?
Hylas: Without question, that which is conceived is in the mind.
Philonous: How then came you to say, you conceived a house or tree existing independent and out of all minds whatsoever?” (Three Dialogues between Hylas and Philonous, first dialogue).
Now since both passages above present an informal argument, let us re-write it as the following mixed conditional syllogism:
Major premise: If conscious ideas/sensations cannot even be conceived without a mind, then conscious ideas/sensations cannot exist externally or independently of a mind.This argument is formally valid. Let us assume that its major premise is sound, to make it easy for the idealist.
Minor premise: Conscious ideas/sensations cannot even be conceived without a mind
Conclusion: Therefore conscious ideas/sensations cannot exist externally or independently of a mind.
It follows that the conclusion is necessarily true.
What does this prove? It certainly does not prove that an external world of matter, containing objects on which some of our ideas/sensations/perceptions are causally dependent, does not exist.
As Stoneham (2009: 121) argues, it is only evidence in support of Berkeley’s proposition (2) above. That is, it proves only that conscious sensations or ideas of any type cannot exist independently of minds. But this is not denied by modern indirect realist materialists/physicalists.
In short, the “master argument” is no devastating demolition of the indirect realist arguments for the reality of an external world of matter and energy as described by science: it is consistent with it.
If Berkeley has some definitive argument against the existence of an external world of matter, the master argument does not qualify for such an argument.
Let us now turn to some other criticisms of both Berkeley’s idealism and the non-theist versions.
II. The Consistency of Conscious Experience
There is a high degree of consistency in the passive sense data or certain “objects of perception” that we cannot control, both between different people and in the same mind over time.
Berkeley does not deny this. Berkeley admits that some ideas of sensation and perception (as opposed to dreams or imagination) are given to the mind and not freely determined by the conscious mind (Musgrave 1993: 127). Regularities in our experience are “laws of nature” for Berkeley (Musgrave 1993: 128).
It would appear that the consistency requires an explanation. In fact, Berkeley did invoke a common cause and an external cause (external to the mind of the individual) to account for it: a theistic god. His explanation is that a theistic god of the type familiar from Judeo-Christian theology is the cause of the consistency of our sensory experiences, and he must be a benevolent one for he does not engage in pernicious and confusing changes in our normally consistent “objects of perception.”
But that raises a whole set of assumptions and the need for a rock-solid argument for the existence of god, something which, as modern philosophy has shown, is a highly problematic exercise.
But what about the non-theistic idealist? The observation about consistency becomes a “brute fact” for the non-theistic idealist. He cannot really explain it, and this leads me into my third criticism.
III. Non-Theistic Idealism has weak Explanatory Power
A final argument against non-theistic idealism is that it is utterly incapable of providing any answers to fundamental question about existence:
(1) why do we have a conscious existence with a high degree of consistency and what looks like external constraints facing us?;One could add a welter of other questions to these, but the conclusion is clear: the explanatory power of idealism is feeble and weak (Musgrave 1988: 241), and the idealist must shrug his or her shoulders and proclaim that we cannot even begin to seriously answer these questions.
(2) where do minds come from?;
(3) in fact, how can you justify the view that other minds even exist? (why doesn’t non-theistic idealism collapse into solipsism?);
(4) if the idealist accepts that other minds exist, do animals have minds?
By contrast, the indirect realist materialist can provide convincing answers to all these questions from our best scientific theories and inductive argument.
For example, take point (3): the charge that non-theistic idealism leads to solipsism. If the only direct experience you have of conscious minds is inside your own conscious mind and one does not believe in the existence of an external world of matter, then what reason is there to think that any other minds even exist?
For the materialist, one strong and straightforward argument is that we have a strong degree of empirical evidence that human minds are causally dependent on brains, and empirical investigations of other human beings show that they have brains (either by non-invasive scanning technologies or sometimes surgery on living humans or autopsies on dead ones). It is therefore a convincing inductive inference that other human minds exist.
In short, here as in numerous other questions, an indirect realist materialism provides a theory with a rich and powerful explanatory power, which is lacking in idealism.
For a defence of idealism and a somewhat different interpretation of the master argument, see Philip Pilkington’s posts here:
Philip Pilkington, “Berkeley’s ‘Master Argument’ Doesn’t Exist,” Fixing the Economists, January 3, 2014.
Philip Pilkington, “Faith-Based Arguments in Empirical, Causal and Probabilistic Reasoning,” Fixing the Economists, October 4, 2013.
Philip Pilkington, “The Theory of Relativity: Anticipated at the Turn of the Seventeenth Century by George Berkeley,” Fixing the Economists, October 5, 2013.
Philip Pilkington, “Berkeley’s ‘Master Argument’ Doesn’t Exist,” Fixing the Economists, January 3, 2014
Freeley, and Austin and David Steinberg. 2014. Argumentation and Debate: Critical Thinking for Reasoned Decision Making (13th edn.). Wadsworth Cengage Learning, Boston, MA.
Gallois, A. 1974. “Berkeley’s Master Argument,” Philosophical Review 83: 55–69.
Grayling, A. C. 2005. “Berkeley’s Argument for Immaterialism,” in Kenneth P. Winkler (ed.), The Cambridge Companion to Berkeley. Cambridge University Press, Cambridge and New York. 166–189.
Mandik, Pete. 2014. This is Philosophy of Mind: An Introduction. Wiley Blackwell, Chichester.
Musgrave, Alan. 1988. “The Ultimate Argument for Scientific Realism,” in R. Nola (ed.), Relativism and Realism in Science. Kluwer Academic Press, Dordrecht. 229–252.
Musgrave, Alan. 1993. Common Sense, Science and Scepticism: A Historical Introduction to the Theory of Knowledge. Cambridge University Press, Cambridge and New York.
Rickless, Samuel Charles. 2013. Berkeley’s Argument for Idealism. Oxford University Press, Oxford.
Robinson, Howard. 2003. “Berkeley,” in Nicholas Bunnin and E. P. Tsui-James (eds.), The Blackwell Companion to Philosophy (2nd edn.). Blackwell, Malden, Mass. and Oxford, UK. 694–708.
Stoneham, Tom. 2009. “Berkeley. Arguments for Idealism,” in Robin Le Poidevin, Peter Simons, Andrew McGonigal, Ross Cameron (eds.), The Routledge Companion to Metaphysics. Routledge, London and New York. 119–130.