Introduction to Philosophy (Fall '09) - class#10

Introduction to Philosophy (Fall '09) - class#10 -...

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Unformatted text preview: Organizational Information First graded assignment was handed out in First discussion section last Friday (10/2) and will be collected at the beginning of discussion section tomorrow (10/9). tomorrow from today: Thursday, October 15. from No class next Tuesday. Our next class is a week No Reading for next time: William Paley’s Natural Reading Theology Chapters 1, 2, and 5 (sections I-IV) Theology Bartlett 65. Bartlett Midterm Exam October 22nd at 7pm - 9pm in Midterm There will be no class the during the day on the There day of the midterm. Descartes Review From Last Time In Meditation 6 Descartes sets out to In establish two final and crucially important propositions: important (1) that he can know for certain that material that things do exist, and things that his mind is really and truly distinct that from his body. from (1) Review From Last Time Though in the previous Meditations Descartes takes Though himself to established with certainty himself that he exists and is a thinking thing (Meditation 2), that God exists (Meditation 3 and 5), that it is possible that there be material objects and that if that if there are material objects, their essential properties are their mathematical properties (Meditation 5), mathematical none of this yet establishes that there are in fact any none material things. material So in Meditation 6 he seeks to show that we can So know with certainty that there are in fact material things in the world. things Review From Last Time Argument For the Existence of Material Things (1) (2) (3) If my sensory perceptions of material things are If not caused by material things, then God is a deceiver. deceiver. It is not the case that God is a deceiver. Therefore, it is not the case that my sensory Therefore, perceptions of material things are not caused by material things. material 1,2 MT So my sensory perceptions of material So things are caused by material things. things Review From Last Time Justification for Premise 1: My sensory perceptions aren’t caused by me My because they occur to me against my will. because So they must either be caused by material things So themselves or by God. themselves But if God caused them, then because I can have But no way of knowing that they are caused by God and I am naturally inclined to believe that they come from material things, God would be deceiving (or allowing me to be deceived) into thinking that there are material things. thinking God is perfect and deception is an imperfection. Justification for Premise 2: Review From Last Time Though Descartes takes himself to have Though established, by way of this argument, not only that material objects exist, but also that our sensory perceptions of material objects are caused by those objects, he doesn’t concede that our perceptions of them resemble them exactly. exactly. He does grant that they are, in some ways, like He how we perceive them to be. how But he only allows that material things have the But properties that we vividly and clearly understand them to have. Review From Last Time “…. So bodies exist. They may not all So correspond exactly with my sensory intake of them, for much of what comes in through the senses is obscure and confused. But at least bodies have all the properties that I vividly and clearly understand, that is, all that fall within the province of pure mathematics.” within the material things that we seem to perceive do in fact exist and that they have all the mathematical properties that they seem to have. have. So, Descartes claims, we can be certain that So, Meditation 6 “However, some of what I thought I had learned from However, nature really came not from nature but from a habit of rushing to conclusions; and these beliefs could be false. Here are a few examples: false. that if a region contains nothing that stimulates my that senses, then it must be empty; senses, that the heat in a body resembles my idea of heat; that the colour I perceive through my senses is that also present in the body that I perceive; also that in a body that is bitter or sweet there is the that same taste that I experience, and so on; same that stars and towers and other distant bodies that have the same size and shape that they present to my senses.” my Meditation 6 If there are material things, then there is a particular If material thing that Descartes can be sure exists because like other material things he perceives it: like His body! Descartes admits that the material thing that he ordinarily Descartes thinks to be his body is intimately related to him in many significant ways. significant But, even so, he argues, he is not identical to his body, But, and, in fact, he is distinct from it. and, He knows he is identical with his mind. (He is certain that He he is a thinking thing, recall.) And he offers an argument for the distinctness of his mind and his body. for Meditation 6 Descartes’s first argument for the Descartes’s distinctness of mind and body has two parts: parts: It is conceivable that my mind exist without my It body. body. If it is conceivable that my mind exist without my If body, then it is possible that my mind exist without my body. my Therefore, it is possible that my mind exist without Therefore, my body. my 1,2 MP Mind/Body Distinctness Argument Part I 1. 2. 3. Meditation 6 Mind/Body Distinctness Argument Part II 1. It is possible that my mind exist It without my body. without 2. If it is possible that my mind exist If without my body, then my mind is distinct from my body. distinct 3. Therefore, my mind is distinct from my Therefore, body. body. 1,2 MP Meditation 6 Back to Part I of the Argument Mind/Body Distinctness Argument Part I 1. It is conceivable that my mind exist without my body. 2. If it is conceivable that my mind exist without my body, then it is If possible that my mind exist without my body. possible 3. Therefore, it is possible that my mind exist without my body. 1,2 MP Justification for premise 1 of Part I: I can conceive of (imagine) what it would be like can if I existed but I didn’t have a body at all if Meditation 6 Justification for premise 2 Justification If it is conceivable that my mind exist without my body, then it is possible that my mind exist without my body. possible of Part I: Whatever I can conceive God could bring about. So, if I can conceive of my mind existing without So, my body, then God could bring it about that my mind exist without my body. mind And if God could make it the case that my mind And exists without my body, then it’s possible that that be the case. be “I know that if I have a vivid and clear thought of know something, god could have created it in a way that exactly corresponds to my thought.” exactly Meditation 6 Now to Part II of the Argument Mind/Body Distinctness Argument Part II 1. It is possible that my mind exist without my body. 2. If it is possible that my mind exist without my body, then my If mind is distinct from my body. mind 3. Therefore, my mind is distinct from my body. 1,2 MP Justification for premise 1 of Part II: Mind/Body Distinctness Argument Part I Meditation 6 Justification for premise 2 Justification If it is possible that my mind exist without my body, then my mind is distinct from my body. from of Part II: Principle of the Indiscernibility of Identicals (PII): If x has ): a property that y does not have, then x ≠ y. (This principle is also sometimes known as Leibniz’s Law.) (This Leibniz’s But if it is possible that my mind exist without my body, then But my mind has the following property: my being possibly able to exist without my body But my body certainly does not have the property: being possibly able to exist without my body So there is a property that my mind has that my body does So not have. not And so if it is possible that my mind exist without my body, And since PII is true, it must be the case that my mind ≠ my PII body. body. (By ‘my mind ≠ (By my body’ I mean my mind is not identical to my body, or, in other words, that my mind is distinct from my body.) body, Meditation 6 But the Mind/Body Distinctness Argument is But not the only argument for the distinctness of mind and body in Meditation 6. mind There is yet another argument for this conclusion There that Descartes offers in Meditation 6. that I will call this argument the Mental Indivisibility will Argument. Argument. Meditation 6 “There is a great difference between the mind and the There body. Every body is by its nature divisible, but the mind can’t be divided. When I consider the mind--i.e., consider myself purely as a thinking thing--I can’t detect any parts within myself; I understand myself to be something single and complete. The whole mind seems to be united to the whole body, but not by a uniting of parts to parts, because: If a foot or arm or any other part of the body is cut off, nothing is thereby taken away from the mind. As for the faculties of willing, of understanding, of sensory perception and so on, these are not parts of the mind, since it is one parts and the same mind that wills, understands and perceives. They are (I repeat) not parts of the mind, because they are parts properties or powers of it. By contrast, any corporeal thing properties powers can easily be divided into parts in my thought; and this shows me that it is really divisible.” shows Meditation 6 The Mental Indivisibility Argument 1. My body is divisible but my mind is not My divisible. divisible. 2. If my body is divisible but my mind is If not divisible, then my mind is distinct from my body. from 3. Therefore, my mind is distinct from my Therefore, body. body. 1,2 MP Meditation 6 Justification for premise 1: That his body is divisible seems obvious. It That can be broken down into parts. can That his mind is not divisible, Descartes That thinks, can be shown by introspection. thinks, “When I consider the mind--I.e., consider When myself purely as a thinking thing--I can’t detect any parts within myself.” any Meditation 6 Justification for premise 2: Here we have another application of the Principle Here of the Indiscernibility of Identicals (PII). of My body has the property: being divisible My mind does not have the property: being divisible So there is a property that my body has that my So mind does not have. mind And so, if my body is divisible and my mind is not, And since PII is true, then it must be the case that my mind ≠ my body. ...
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This note was uploaded on 10/12/2010 for the course PHIL 100 taught by Professor Jeremy during the Spring '08 term at UMass (Amherst).

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