Mind s Eye Idea Object

Transcription

1 Do the ideas in our mind resemble the qualities in the objects that caused these ideas in our minds? Mind s Eye Idea Object Does this resemble this?

2 In Locke s Terms Even if we accept that the ideas in our mind are caused by real objects that exist outside our minds (Locke never really questions this) Is it true that our ideas always resemble the qualities in the objects that caused us to have those ideas?

3 Locke s Answer Only sometimes. Some of our ideas do resemble qualities in the objects, but some of them do not. Our ideas of primary qualities resemble those qualities. Our ideas of secondary qualities do not.

4 Why? In sense experience, objects cause us to have sensations. Locke says that sensations don t always resemble the qualities of these objects. Why? Why don t our ideas always resemble the qualities in the objects that cause us to have those ideas?

5 Explaining the difference

6 Explaining Sensations We have scientific explanations for how objects can cause us to have sensations. They explain how different properties in objects cause different kinds of sensations in us. Exp.: Seeing red vs. seeing blue. Different qualities effect our sense organs differently, and cause different kinds of sensations or ideas in our minds. These qualities need not resemble the sensations they cause.

7 Sensations as Effects So, sensations are the effects of causal interactions with the world. But effects need not resemble their causes. Smoke doesn t resemble fire! Our sensations of color, sound, taste, smell, and temperature don t resemble the qualities in the object that cause us to have those sensations.

8 So, Objects outside our minds cause sensations in our minds. Different properties of objects cause different kinds of sensations. Science hypothesizes the properties objects must really have to explain the ideas we have of them. As long as a specific quality in the object uniformly causes a certain kind of sensation in us, there is no reason that these qualities need to resemble the sensations that they cause.

9 Sensations of blue vs. the quality of being blue So, being blue (a secondary quality) is a property an object has because it has the power to cause certain kinds of ideas in our minds. It has this power because of the primary qualities of the particles out of which it is composed, and how these particles interact with our bodies in sense perception. So the power, or quality of being blue, is what causes us to have certain kinds of sensations, which we call sensations of blue.

10 Being Blue So the blueness of a blue chair is real, but is not a fundamental quality of the particles the chair is composed of. The blueness of the chair is explained in terms of the fundamental properties of the particles out of which it is composed. I.e., the secondary quality (of being blue) just is the quality of being composed of particles with certain primary qualities. This is what makes them secondary they are explained in terms of combination of more basic primary qualities.

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12 Where did Blue go? Which is blue? The sensation (idea) in our mind, or The quality (power) in the object? Blue is a quality of objects. Sensations aren t blue, any more than they are heavy! Sensations are of blue.

13 Stop me if you ve heard this one.

14 Falling Trees You ve all heard this one: If a tree falls in the forest with no one there to hear it, does it make any sound? How do you think Locke would answer this question. What does science tell you? Hint: The correct answer is: Yes and No.

15 Answer The tree in the forest disturbs air waves whether or not there is anyone there to hear it. (This is realism. ) But if no one is present, it doesn t produce any auditory sensations in anyone s mind. The confusion: We use the word sound both to talk about airwaves and to talk about sensations. But these are different things. The falling tree disturbs air waves (makes a sound on one use), but doesn t cause any sensations (doesn t make a sound, on the other use).

16 A problem? On this view, all we are ever directly conscious of in sense experience are the ideas or sensations that exist in our minds. We cannot, even in principle, ever get outside our own minds to see if we are correct about the objects, according to the theory, that cause our sensations. We only see the effects, never the causes. So, how could we know for sure whether or not our sensations ever resemble their causes, or even if these external objects even exist in the first place?

17 George Berkeley The Principles of Human Knowledge

18 To be is to be perceived

19 Obvious to the Mind all those bodies which compose the earth have no subsistence without a mind, their being is to be perceived or to be known [Principle 6] their esse is percipi [Principle 3] their being is in being perceived. Trees, tables, human bodies, etc., exist only in being perceived; exist only in our minds! it follows, there is not any substance other than spirit, or that which perceives. [Principle 7]

20 Berkeley s Idealism: There is no such thing as material substance. Real things like tables, mountains, etc., exist only in being perceived. Their esse ( being ) is percipi ( being perceived ). The only real substance is mental, i.e., the only things that exist in the universe are mind/souls (and the ideas that exist in them). Things, like tables and chairs, mountains and bodies, exist only in our perceptions of them. They exist only in our minds.

21 Berkeley Rejects (Metaphysical) Realism Realists, like both Descartes and Locke, believe that there is a world (the material world) that exists independently of whether or not any conscious mind experiences it. Berkeley rejects this. there is not any substance other than spirit Berkeley s position is known as (metaphysical) idealism.

22 Mind/Body Dualism Descartes and Locke both believe that mind and body (matter) are two fundamentally distinct and irreducible kinds of basic stuff or substance that constitute the basic fabric of reality. We ll look at arguments for and against this position in our next chapter. Dualists believe that minds or souls have a distinct existence from the bodies (material objects) they occupy.

23 Berkeley Rejects Mind/Body Dualism Dualists, like both Descartes and Locke, believe that the world contains two fundamentally different kinds of stuff mind and matter. Berkeley disagrees: He believes in the existence of mind; that which perceives He does not believe in the existence of matter.

24 Berkeley Believes that, in the end, minds (souls, spirits, immaterial substances) are the only sorts of things that exist. Believes that bodies (all the things we can perceive with our senses) exist only in our consciousness of them they are nothing but collections of ideas.

25 Locke s Causal Theory of Perception: Indirectly aware of Sensation Berkeley simply REJECTS this part of Locke s picture. Matter

26 Compare and Contrast

27 Locke: Whatsoever the mind perceives in itself, or is the immediate object of perception, thought, or understanding, that I call idea That is, Locke believes that in perception, thought, [and] understanding, in all forms of conscious awareness what we are immediately aware of are always/only ideas in our minds.

28 Berkeley: It is evident [that] the objects of human knowledge are either ideas actually imprinted on the senses, or else such as are perceived by attending to the operations of the mind [such as] memory and imagination. Berkeley agrees that in all forms of conscious awareness, what we are immediately aware of are always/only ideas in our minds.

29 Locke and Berkeley Agree: The only immediate objects of thoughts, sensations, perceptions, etc. (of any conscious experience) are ideas or sensations, i.e., things that exist only in our minds.

30 Where they disagree: Is there any world beyond (independent of) our ideas? Locke: Yes. Berkeley: No.

31 Berkeley s Idealism

32 Berkeley s View: Real objects are collections of ideas. Objects (tables, chairs, bodies, etc) are simply collections of ideas that exist only in being perceived. This is Berkeley s Idealism.

33 Defending Idealism by Rejecting Materialism

34 Berkeley s Idealism: There is only one fundamental kind of thing, mental things, i.e., minds or souls (and the ideas that are in them). (What Berkeley calls) Materialism: The view that there are material things (that there is a material substance ) in addition to mental things. This is what we called dualism. Later philosophers will use the term materialism for those who accept matter but deny mental substance.

35 Berkeley s Claim: Materialism leads to skepticism Even if it is possible that solid, figured, moveable substances exist without the mind, yet how is it possible for us to know this? If all that we directly know or experience are ideas in the mind (mental entities), we have no evidence for the existence of anything distinct from these ideas.

36 Directly Known Material Substance: Only inferred We are directly aware only of ideas. Locke: We infer material objects as the causes of these ideas. Berkeley challenges this inference.

37 Even if we grant that we don t directly perceive material substances, can t we infer them as the best explanation of the ideas and sensations that we do perceive? Berkeley: But by their own confession they own themselves unable to comprehend in what manner body can act upon spirit. --i.e., positing the existence of matter doesn t really explain anything, since you can t actually explain how matter causally influences mind.

38 they [are] unable to [explain how] body can act upon spirit. For Dualists (like Locke and Descartes), mind and matter are two distinct kinds of substances they have nothing in common. But if they have nothing in common, how can they causally interact with one another? How can mind ( spirit ) make matter move? How can matter ( body ) cause ideas in a (non-material) mind?

39 ? Berkeley: How could mind causally interact with matter?