Berkeley’s Idealism

1. Berkeley’s Idealism Principles of Human Knowledge George Berkeley Esse is percipi

2. Berkeley was Irish Sure and ‘tis sometimes said we Irish Men think backward to everyone else. -----Berkeley Notebooks • Born 1685 near Kilkenny; died Oxford 1753 • Work in optics, foundations of calculus • In America, trying to open theological college • Anglican Bishop of Cloyne • Principles of Human Knowledge,Three Dialogues arguing for idealism

3. Anyone who surveys the objects of human knowledge will easily see that they are all ideas that are either actually imprinted on the senses or perceived by attending to one’s own emotions and mental activities or formed out of ideas of the first two types, with the help of memory and imagination.

4. Skepticism • “I know the meaning but I don’t know the analysis” • How theory-laden is language? • Eddington’s table • numbers • Berkeley’s “revisionary metaphysics”: ordinary language isn’t very theory laden so • We should “speak with the vulgar but think with the learned” • “The sun rises”

5. What we will consider… • Ontology: Berkeley’s Immaterialism • Arguments and criticism of arguments including… • The Core Argument (PHK 4) • The Refrigerator Light Gotcha Argument (“The Master Argument” in PHK 22-23) • Some objections and responses to Berkeleian idealism • The persistence of unperceived objects • The distinction between reality and illusion/dreaming • The legitimacy of Science

6. On what there is Ontology: Berkeley’s World

7. Berkeley’s Ontology Ontology

8. What is there? • Dualism: There are two different kinds of substances—material substance and spiritual substance (vide Descartes) • Materialism: Everything is material; only material objects exist. (contemporary variant, Physicalism) • Berkeleian Idealism (“Immaterialism”): There are only spiritual substances (finite substances and God) and their ideas. • To be is to be perceived • or to be a perceiver.

9. Spirits and Ideas • The only substances are spiritual substances, i.e. God and finite spirits • There is no material substance (contra Locke) in which sensible properties “inhere” • Spirits have ideas (not vice versa) • Spirits are active, causes—ideas are inert, have no causal power • There are only ideas and the spirits that have them: To be is to be perceived or to be a perceiver

10. Why should we accept this ontoloty? Arguments for Idealism

11. Arguments

12. 1 Ordinary Objects are collections of ideas • The objects of human knowledge...are all ideas • Empiricism: all knowledge comes ultimately through (sense) experience. • The immediate objects of sense experience are ideas. • [W]hen a number of these [ideas] are observed to accompany each other, they come to be marked by one name and thus to be thought of as one thing…[as for example] an apple • Other collections of ideas constitute a stone, a tree, a book, and similar perceptible things. • ’constitute’ ??!!?

13. 2-3, 7 Spirits, Ideas, Persistence of Objects • Spirit is ‘something that knows or perceives them [ideas] and acts on them. • Esse is Percipi: for unthinking things (i.e. ideas and the objects constituted of them) to be is to be perceived. • But objects (e.g. the books in my study) continue to exist even when I’m not around to perceive them. Do they? If so, how? • Berkeley has 2 alternative proposals: • Phenomenalism: ‘If I were in my study I would perceive it’ (objects as ‘permanent possibilities of sensation’) • ‘Some other spirit actually does perceive it’ (i.e. God) • Question: do different spirits have the same ideas?

14. Refrigerator Light & Tree in the Quad “There was a young man who said "GodMust find it exceedingly oddTo think that the treeShould continue to beWhen there's no one about in the quad." Reply:"Dear Sir: Your astonishment's odd;I am always about in the quad.And that's why the treeWill continue to beSince observed by, Yours faithfully, God.” http://www.youtube.com/watch?v=TwhfTExM080&feature=relmfu

15. 4 The Core Argument • It is indeed widely believed that all perceptible objects— houses, mountains, rivers, and so on—really exist independently of being perceived by the understanding. • But… [this belief] involves an obvious contradiction. • For what are houses, mountains, rivers etc. but things we perceive by sense? • And what do we perceive besides our own ideas or sensations? • And isn’t it plainly contradictory that these, either singly or in combination, should exist unperceived? [PHK 4]

16. All we perceive are ideas…and ideas are mind dependent The Core Argument

17. 4 The Core Argument (1) Ordinary objects are perceived by sense. (2) All things perceived by sense are ideas. (3) So ordinary objects are ideas. (4) But ideas do not exist unperceived. (5) So ordinary objects do not exist unperceived

18. 5 Against Abstraction • Introduction: against Locke’s theory of abstract ideas • Locke’s picture: we get the general idea of, e.g. triangle by forming an ‘abstract’ idea of a triangle that’s neither equilateral, scalene, or whatever…. • Berkeley: no such thing--abstraction thus understood is impossible. • Can’t ’abstract’ the sensation/perception of a perceptible thing from the thing. • Note: Berkeley has an elaborated version of this argument, ‘The Master Argument’ so-called, in 22 - 23.

19. Against Abstraction [W]e are told ·by the supporters of ‘abstract ideas’·, the mind can consider each quality on its own, abstracted from the others with which it is united in the object, and in that way the mind forms abstract ideas…I deny that I can perform ‘abstraction’ in the standard meaning of that word, which covers two kinds of mental performance: • conceiving abstractly and in isolation a quality that couldn’t exist in isolation ·as we are said to do with colour and motion·; and • forming a general notion by abstracting from particulars in the way I have described, ·as we are said to do with man and animal·. There is reason to think that most people are like me in this respect. [PKH Intro 7, 10]

20. Ideas are inert • Argument for the inertness of ideas [PHK 25] • Since ideas are mind-dependent, they only the characteristics that they’re perceived to have. • We don’t perceive them to have causal power • So they must be causally inefficacious. • Note: Berkeley appeals to the inefficaciousness of ideas in a novel argument for the existence of God.

21. On the inconceivability of things existing unconceived The Master Argument

22. 22 - 23 ‘The Master Argument’ ‘surely there is nothing easier than to imagine trees in a park, for instance, or books on a shelf, with nobody there to perceive them.’ …You form in your mind certain ideas that you call ‘books’ and ‘trees’, and at the same time you omit to form the idea of anyone who might perceive them. But while you are doing this, you perceive or think of them! So your thought- experiment misses the point; it shows only that you have the power of imagining or forming ideas in your mind; but it doesn’t show that you can conceive it possible for the objects of your thought to exist outside the mind. To show that, you would have to conceive them existing unconceived or unthought-of, which is an obvious contradiction. However hard we try to conceive the existence of external bodies, all we achieve is to contemplate our own ideas. The mind is misled into thinking that it can and does conceive bodies existing outside the mind or unthought-of because it pays no attention to itself, and so doesn’t notice that it contains or thinks of the things that it conceives. [PHK 23]

23. 22 - 23 Conceivability and Logical Possibility Note: ‘perceive’ for Berkeley means ‘think about’ or ‘conceive of’ so Berkeley’s esse is percipi claims that, for non-spirits, to be is to be thought-about. • A state of affairs is logically possible only if it’s conceivable • We cannot conceive of a state of affairs in which there are unthoughtabout objects Try it…gotcha! • Therefore, it is logically impossible that unthought-about objects exist.

24. 22 - 23 Can unthought of objects be thought of? Yes and No • ‘Unthought about objects can be thought about’ is ambiguous • It is possible that there be an object that I’m thinking about now that is not being thought about now. [Berkeley’s interpretation] • An object that I’m thinking about now is such that it’s possible that it not be thought about. • 1 is a contradiction; 2 is not. • Compare: ‘I can’t tell you the secret because if I did then it wouldn’t be a secret’.

25. Behind the Veil of Perception Against Representationalism

26. Responses to the Core Argument • We perceive ordinary objects • We perceive only ideas • Therefore, ordinary objects are ideas There are (at least) two ways to defeat this argument: • Direct Realist Response: premise 2 is false. We perceive ordinary material objects directly. • Representationalist Response: “perceive” is ambiguous and means something different in premises 1 and 2 • Mediate & Immediate Perception • 2’. We immediately perceive only ideas (argument fails!)

27. The Classic Alternatives Direct (“Naïve”) Realism Sense Data Theories The objects of immediate experience are sense-data or “ideas” Representationalism: the immediate objects of experience represent the physical objects that cause them. Phenominalism: physical objects are reducible to the occurrence of immediate objects of experience. Physical objects are directly (“immediately”) perceived • We don’t need to justify any inferences from objects of sensory experience to physical reality because physical objects are the objects of sensory experience.

28. Problems Direct Realism: we do need justification for beliefs about physical objects. • Argument from illusion: cases of non-veridical perception • Argument from perspectival differences • Argument from the scientific account of perception: the intervening medium affects experience, the finite speed of light. • Representationalism: we can’t know either that there are objects outside of experience that cause experience or that whatever objects there are ‘out there’resemble the objects of immediate experience (i.e. sense data) • We can’t observe the alleged causal connection. • We can’t observe the alleged resemblance.

29. Representationalism immediately perceived mediately perceived • Things ‘out there’ (material objects) both cause and resemble our ideas. • Berkeley: (1) ideas are ‘inert’ so can’t cause and (2) an idea can’t resemble anything but another idea

30. 8 Against Representationalism ‘But’, you say, ‘though the ideas don’t exist outside the mind, still there may be things like them of which they are copies or resemblances, and these things may exist outside the mind in an unthinking substance.’ I answer that the only thing an idea can resemble is another idea…you can’t conceive of any likeness except between your ideas. Also: tell me about those supposed originals or external things of which our ideas are the pictures or representations—are they perceivable or not? If they are, then they are ideas, and I have won the argument; but if you say they are not, I appeal to anyone whether it makes sense to assert that a colour is like something that is invisible; that hard or soft is like something intangible; and similarly for the other qualities.

31. Resemblance and Causation • Representationalism: ideas are caused by external objects which resemble them (in cases of veridical experience) • Likeness Principle: An idea can be like nothing but an idea (PHK 8) • Two things cannot be said to be alike or unlike till they have been compar'd(notebooks) • IBE?: [T]hey [materialists] by their own confession are never the nearer knowing how our ideas are produced. (PHK 18) • We could have our ideas without their being external objects that resemble them causing them (could be God) • How can things cause ideas? (see e.g. Elizabeth to Descartes on mind-body causation.)

32. RepresentationalismSkepticism Veil of Perception But…how could I compare? Or assume cause?

33. Berkeley rejects Representationalism • Representationalism forces us to skepticism since we can’t know how our ideas are caused or whether they resemble whatever causes them Suppose it were possible for solid, figured, movable substances to exist outside the mind, corresponding to the ideas we have of bodies—how could we possibly know that there are any such things? [PHK 18] • Representationalism is incoherent since non-ideas can’t literally resemble ideas—since they can’t in principle be compared • ‘But’, you say, ‘though the ideas don’t exist outside the mind, still there may be things like them of which they are copies or resemblances, and these things may exist outside the mind in an unthinking substance.’ I answer that the only thing an idea can resemble is another idea [PHK 8]

34. 9 - 15 Relativity Arguments Large and small, and fast and slow, are generally agreed to exist only in the mind. That is because they are entirely relative: whether something is large or small, and whether it moves quickly or slowly, depends on the condition or location of the sense-organs of the perceiver. • Observer-relativity of a sensible quality shows that it’s “subjective” i.e. our sensation doesn’t resemble a cause “out there.” • All sensible qualities (“primary” as well as “secondary”) are observer-relative • Therefore, all sensible qualities are subjective.

35. 16 - 21 Berkeley on Material Substance • The notion of Material Substance (vide Locke) is incoherent—and promotes to atheism: How great a friend material substance has been to atheists in all ages were needless to relate. All their monstrous systems have so visible and necessary a dependence on it that when this corner-stone is once removed, the whole fabric cannot choose but fall to the ground insomuch that it is no longer worth while to bestow a particular consideration on the absurdities of every wretched sect of atheists. [PHK92]

36. 16 - 21 Against Material Substance • ‘It is said that extension…is the substratum that supports [extension]’ What does this mean? Can’t be literally true. • ‘Suppose it were possible for solid, figured, moveable substances to exist outside the mind...how could we know there are any such things?’ Skepticism! • Sense gives us only knowledge of ideas • Reason (inference from sense) doesn’t license us in assuming that the cause of our ideas is ‘external’ • IBE (Inference to Best Explanation) doesn’t give us reason to believe that the causes of our ideas are caused by external objects. • 21 ‘ If there were external bodies we couldn’t...know this...if there weren’t’ same as now.

37. Berkeley responds to 12 objections--good, bad, and indifferent Berkeley’s Response to objections

38. Objections TO BE CONTINUED…

39. Immaterialism doesn’t mean everything is an illusion Real things

40. 34 - 40 Objection 1: Real Things & Chimeras • Objection: By your principles everything real and substantial in nature is banished out of the world, and replaced by a chimerical system of ideas. All things that exist do so only in the mind ·according to you, that is, they are purely notional. • Assumes that the distinction between our experience of real things and illusions is that our ideas of real things correspond (in some way) to things external to and independent of us. • Berkeley: I don’t in the least question that the things I see with my eyes and touch with my hands do exist, really exist. The only thing whose existence I deny is what philosophers call ‘matter’ • The distinction isn’t what you think it is, Objector!

41. 37 Substance • History of Substance • Aristotle: something of which things are said, including ordinary objects. • Locke: substratum, ‘something I know not what’ • Berkeley admits substances as ordinarily understood, i.e. ordinary objects: ‘combinations of perceptible qualities such as extension, solidity, weight, etc.’ • i.e. collections of ideas • Berkeley rejects substance in the philosophical sense--Lockean substratum--existing independent of mind.

42. 33 Real Things the principles I have laid down don’t deprive us of any one thing in nature. Whatever we see, feel, hear, or in any way conceive or understand remains as secure as ever, and is as real as ever. There is a real world, and the distinction between realities and chimeras retains its full force…real things and chimeras both exist in the mind, and in that sense are alike in being ideas. [PHK 34] • Ideas of real things are “caused by the will of a more powerful spirit, namely God” [PHK 33] • We can recognize them because they’re more regular, vivid and constant [PHK 33]

43. 40 Evidence of the Senses • Objection: ‘Say what you like, I will still believe my senses, and will never allow any arguments, how- ever plausible they may be, to prevail over the certainty of my senses.’ • Berkeley: I don’t see how the testimony of the senses can be brought as proof of the existence of anything that is not perceived by sense.

44. 41 Objection 2: Pain Dr. Johnson: ‘ Thus I refute him!

45. Has Berkeley proved too much? The possibility of error

46. Esse is Percipi Ordinary physical things exist only if, and only when, they are “perceived,” i.e. thought-about: there are no unthought-about things! All the choir of heaven and furniture of the earth, in a word all those bodies that compose the mighty structure of the world, have no existence outside a mind; (1) for them to exist is for them to be perceived or known; consequently (2) so long as they aren’t actually perceived by (i.e. don’t exist in the mind of) myself or any other created spirit, they must either have no existence at all or else exist in the mind of some eternal spirit; because it makes no sense—and involves all the (3) absurdity of abstraction—to attribute to any such thing an existence independent of a spirit.

47. Optical ( and Other) Illusions • Hylas. [H]ow can a man be mistaken in thinking the moon a plain lucid surface, about a foot in diameter; or a square tower, seen at a distance, round; or an oar, with one end in the water, crooked • Philonous. He is not mistaken with regard to the ideas he actually perceives; but in the inferences he makes from his present perceptions. Thus in the case of the oar, what he immediately perceives by sight is certainly crooked; and so far he is in the right. But if he thence conclude, that upon taking the oar out of the water he shall perceive the same crookedness; or that it would affect his touch, as crooked things are wont to do: in that he is mistaken. (3D 238)

48. 42 - 44 Objection 3: The Perception of Distance • Objection: we see things actually outside us, at a distance from us; and these things don’t exist in the mind, for it would be absurd to suppose that things that are seen at the distance of several miles are as near to us as our own thoughts. • Berkeley: Distance or externality is not immediately of itslef perceived by sight…Rather it was only suggested to our thoughts by certain visible ideas and sensations...in no way similar to or related to either distance or things at a distance. (PHK 43) • The ideas of sight and touch constitute two species entierely distinct...The former are marks and forward-looking signs of the latter. [PHK 44] • The Molineaux Problem: A man who was born blind...

49. 54 Objection 8: Common Beliefs • Objection: Must we suppose the whole world to be mistaken?—·the objection runs·—and if so, how can we explain such a wide-spread and predominant error? • Berkeley: They don’t really believe that things exist unperceived because that involves a contradiction • The source of belief in mind-independent objects: we have ideas of which we ourselves are not the authors and mistakenly imagine that they’re caused by objects that resemble them--rather than God. • Mistake: things like ideas exist outside of minds • Mistake: things like ideas have power or activity

50. Primary and Secondary Qualities, Causation, and Hidden Mechanisms Scientific Explanation