New Chapter: Epistemology: The Theory and Nature of Knowledge

Transcription

1 Intro to Philosophy Phil 110 Lecture 14: 2-22 Daniel Kelly I. Mechanics A. Upcoming Readings 1. Today we ll discuss a. Locke, An Essay Concerning Human Understanding b. Berkeley, Three Dialogues Between Hylas and Philonus 2. Next time a. Hume, An Inquiry Concerning Human Understanding (Excerpt) B. Down the road a bit: 1. Midterm Exam: in class, Thursday 3/1 2. Final Exam has been scheduled: a. Wednesday 05/02 b. 3:30p - 5:30pm c. This Room: Wetherill 172 d. Cumulative New Chapter: Epistemology: The Theory and Nature of Knowledge I. Some Preliminaries II. Descartes ( ) III. John Locke ( ) A. Fun Facts Rationalists Empiricists Descartes: Locke: Spinoza: Berkeley: Leibniz: Hume: B. Rationalism and Empiricism: C. Locke and the Problem of Perception D. Locke s Solution: Limited Representationalism 1. Locke s Argument Against Solipsism 2. Defense of limited representationalism s key insight & distinction a. Variance Argument b. Argument from the success of Newtonian science i. Newtonian physics appeals to the primary qualities of matter, but not the secondary properties A. Newton s laws of motion and gravitation are sensitive to the mass of an object B. But not color, taste, warmth, etc. ii. Since Newtonian physics has been so successful in its prediction and explanations iii. Locke argues that this indicates the science was discovering the important qualities of matter itself c. Extending Locke s argument from Newtonian science

2 i. Modern science has to some extent vindicated Locke s view of this A. The way something tastes or smells to us is largely determined by the shape of the molecules allow them to interact with our tongues or olfactory nerves B. The felt warmth or coldness of matter is largely determined by the speed of their molecular motion and how that interacts with our nerve endings C. Our experience of color is largely determined by the wavelength (size) of the light that hits our eyes ii. We will call Locke s view limited representationalism because it holds that only a limited set of the qualities of matter (namely, the primary qualities) resemble or are accurately represented by the perceptual experiences they cause E. Locke s concluding general remarks on empiricist justification of perception and belief in the external world 1. Locke acknowledges differences between different types of beliefs, and knowledge arrived at in different ways a. Concedes that beliefs based on evidence of the senses will probably never achieve the status of absolute certainty b. Probably never be as immune from doubt as intuitive mathematical ideas and deductive conclusions 2. However, he maintains that those beliefs based on the evidence of the senses are secure enough to deserve to be called knowledge a. Deductive and perceptual beliefs are justified in different ways, and each held to their own standards b. The coherent testimony of the senses may be as much assurance as we are capable of c. In a spirit of common sense, Locke suggests it is also as much assurance as we need to get through the day 3. A passage that seems aimed at Descartes demand for certainty: This shows how foolish and pointless it is for a man to expect demonstration and certainty in things that are not capable of it, and to refuse assent to very reasonable propositions and act contrary to very plain and clear truths, simply because they cannot be made so evident as to surmount every the least (I won t say reason, but) pretence of doubting. If anyone brought that attitude to the ordinary affairs of life, accepting nothing that had not been plainly demonstrated, would be sure of nothing in this world except an early death. The wholesomeness of his meat or drink would not give him reason to risk it. What indeed could he do on grounds that were capable of no doubt, no objection? IV. Berkeley s Answer: Idealism A. Fun Facts ( ) 1. Eccentric Irish genius

3 a. Wrote a book extolling the medicinal values of tar water b. Turned out to be his best selling book in his lifetime 2. The Bishop of Cloyne, a small town in the County Cork, Ireland 3. The US city of Berkeley, California is named after him 4. One of the three most famous British Empirists a. But can be seen as oppositional to Locke b. Started with similar empiricist principles c. Arrived at conclusions that turn common sense on its head B. Berkeley s Idealism 1. Preliminaries a. Philosophical Idealism i. Does not describe someone who sticks to their high moral ideals come hell or high water A. I.e. doesn t describe the type of idealist who might be a opposed to a pragmatist B. Or opposed to someone who has sold out their principles ii. Berkeley s form of idealism might be better be thought of as idea-ism A. Also called immaterialism B. Also called subjective idealism b. The dialogues i. Hylas (Greek for matter ) A. Basically Locke s mouthpiece, or argues in favor of Locke s common sense view B. Supports the pro-matter position ii. Philonous (Greek for lover of mind ) A. Berkeley s mouthpiece B. Argues for the pro-mind, idealist position iii. Ground rules of the debate: whoever s position avoids skepticism about our knowledge of physical objects wins A. If one position can be shown to entail that we cannot know anything about physical objects B. The position should be dismissed as absurd 2. Berkeley s motivation a. Berkeley thinks that idealism is the only theory that can make sense of the manifest fact that we do have knowledge of physical objects b. The only theory about perception and the external world or the causes of perception that i. Can resolve or diffuse the problem of perception ii. Does not lead straightforwardly to skepticism about the causes of perception iii. Avoids solipsism 3. Basic idea of Berkeley s idealism: a. Everything that exists i. Is either a mind itself

4 ii. Or the contents of a conscious mind A. I.e. ideas in a mind B. ideas is being used in a general sense, to include sensations, perceptions, etc. C. From this, we get the name of Berkeley s position, idea-lism b. Surprisingly, Berkeley argues this includes i. What we usually think of as the external world ii. The physical objects in the external world c. Catchy slogan: i. Esse est percipi ii. Latin for to be is to be perceived 4. Berkeley also draws an important distinction between physical objects and matter (sometimes calls it material substance ) a. Physical objects i. Particular ordinary things we perceive in the world around us ii. For example: A. Tasty tacos B. Smelly cats C. The Purdue Bell Tower D. Domed mountains b. Matter i. The very general, mind independent stuff ii. Common sense holds that physical objects are made or composed out of matter iii. That according to Locke s theory A. Has qualities that resemble our ideas of primary qualities B. But does not have any qualities that resemble our ideas secondary qualities iv. Berkeley thinks Locke is wrong about this A. Holds that matter is a philosopher s myth B. In fact, there is no such thing as matter 5. This sets the agenda for the dialogues a. Through a series of arguments b. Berkeley attempt to undermine Locke s key distinction between primary and secondary qualities C. Berkeley s Attack on Locke s Limited Representationalism 1. Berkeley agrees w/ Locke that physical objects are absolutely real a. He disagrees on Locke s claim that physical objects made of matter b. Rather, Berkeley argues that they are made of ideas 2. He gives several arguments in support of this idealist view a. Argument that physical objects are made of ideas i. When we perceive and talk about a physical object, say a taco, we perceiving and talking about something

5 that is (say) hot, has a hard shell, smells good, is about 5 or 6 inches long ii. These are properties that only ideas (conscious experiences) can have iii. Therefore, when we perceive and talk about a physical object like a taco, we are really perceiving and talking about collections of ideas A. We are actually talking about collections ideas even if we don t realize it B. Again, turning common sense on its head C. To be is to be perceived b. Argument from variance and primary qualities i. What about the primary properties of the taco? A. Its shape B. Its appearing to be 5 or 6 inches long ii. Berkeley argues that our ideas of primary qualities are subject to variation in the same way our ideas of secondary qualities are A. Remember Locke s thought experiment with the buckets of water B. Berkeley holds that similar thought experiments can be used to demonstrate variance in perceptions of shape and size 1. The same coin a. Seen up close results in a very large perceptual experience b. Seen from far away results in a very small perceptual experience c. Looked at straight on results in a circular looking perceptual experience d. Looked at from an angle on results in an oval looking, or even a rectangular looking perceptual experience 2. Moreover, to a much smaller creature like a mite a. Objects appearing small to us i. Coin ii. Our own feet b. Would appear as some huge mountain iii. Berkeley concludes there really is no distinction between primary and secondary qualities c. Argument that matter would be inconceivable i. Claims only an idea can resemble another idea ii. Claims perceptions can only resemble other perceptions

6 A. Further suggests that only ideas and sensations can only be produced by minds or other ideas and sensations B. But how can any idea or sensation exist in or be produced by anything but a mind? iii. Since all the mind immediately perceives is ideas, sensations, or perceptual experiences iv. It makes no sense to think there can be matter that doesn t have any qualities like color or smell v. Because we would not be able to grasp, conceive, or think about such stuff A. Hence, we would not be able to know anything about matter B. Since, on Locke s view, physical objects are made of matter, we would not be able to know anything about physical objects 1. Tasty tacos 2. Smelly cats 3. The Purdue Bell Tower 4. Domed mountains C. But this is skepticism! D. So Locke s view is can be rejected as absurd, as per the ground rules of the debate D. Skeptical Objection: The Problem of Unperceived Objects 1. Recall the catchy slogan of Berkeley s idealism: Esse est percipi a. If physical objects are just bundles of perceptions (& ideas) b. Then when no one is actually perceiving (or thinking about) an object, say a tasty taco c. They cease to exist! i. This looks like an absurd implication of Berkeley s idealism A. (Perhaps could be spelled out into a reductio ad absurdum style argument B. Against the initial premises of his position) ii. It is enormously counterintuitive that objects just blink in and out of existence when no one is around to perceive them A. Ask that age old question of philosophy: If a tree falls in the forest, and no one is there to hear it, does it really make a sound? B. On Berkeley s view 1. No it does not 2. If there is not anyone there to hear it, (or see it, or feel it, etc.) 3. There isn t even a tree!