Introduction to Philosophy (Fall '09) - class#6

Introduction to Philosophy (Fall '09) - class#6 -...

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Unformatted text preview: Organizational Information Ungraded assignment answer key Ungraded now online. now You should have downloaded and You printed out the handout for today’s lecture. lecture. Descartes’s Meditations on First Philosophy - Meditation 4 Philosophy Reading for next time: Rene Reading Descartes Review From Last Time In Meditation #2 Descartes takes In himself to have established: himself 1. 2. 3. That it is certain that he exists. That it is certain that he is a thing that That thinks. thinks. That, if he has knowledge or That, understanding of the world around him, understanding he has it not in virtue of his senses, but, rather, in virtue of his understanding through his mind alone. through Descartes is a rationalist and not an empiricist. Meditation #3 In this Meditation Descartes sets out to prove the In existence of God. existence Why? If he can’t prove the existence of God, then he can’t If rule out the possibility that there is an all-powerful deceiver deceiving him in all that he believes. deceiver “I shall examine whether there is a God, and (if shall there is) whether he can be a deceiver. If I don’t settle this, it seems, then I can never be quite quite certain about anything else.” certain of Descartes’s anti-skeptical project. of So, proving the existence of God is a crucial part So, Meditation #3 Descartes’s most famous argument for the Descartes’s existence of God is an argument that has come to be known as The Trademark Argument. The similar to, though, in other respects, importantly different from, a famous argument for the existence of God known as the Ontological Argument offered by St. Anselm in the eleventh century. having a few distinct parts. having The Trademark Argument is, in some respects, The We will present the Trademark Argument as We Meditation #3 1. 2. Trademark Argument Part I My idea of God has a cause. If my idea of God has a cause, then If the amount of reality in the cause of my idea of God is infinite. my 3. Therefore, the amount of reality in the Therefore, cause of my idea of God is infinite. cause 1,2 MP Meditation #3 1. 2. Trademark Argument Part II The amount of reality in the cause of my The idea of God is infinite. idea If the amount of reality in the cause of my If idea of God is infinite, then the cause of my idea of God is perfect. idea The cause of my idea of God is perfect. 1,2 MP 3. Meditation #3 1. 2. Trademark Argument Part III The cause of my idea of God is perfect. If the cause of my idea of God is perfect, If then the cause of my idea of God is God and not me. and Therefore, the cause of my idea of God is Therefore, God and not me. God 1,2 MP 3. Meditation #3 Back to Part I of the argument: 1. 2. 3. My idea of God has a cause. If my idea of God has a cause, then the amount of reality in the If cause of my idea of God is infinite. cause Therefore, the amount of reality in the cause of my idea of God is Therefore, infinite. infinite. 1,2 MP What is the justification of premise 1? Descartes takes it to be undeniable that he has an idea of Descartes God. God. He also takes it to be undeniable that everything has a He cause. cause. So since it is undeniable that he has an idea of God and it So is undeniable that everything has a cause, then it must be the case that his idea of God has a cause. the Meditation #3 What is the justification of the second premise If my idea of God has a cause, then the amount of reality in the If cause of my idea of God is infinite. cause supposed to be? Descartes accepts the following principle: The Causal Adequacy Principle: The actual The reality of the cause of something must be equal to or greater than both the actual reality and the representative reality of that thing. representative On Descartes’s picture, things in the world On have different levels of actual reality. have The higher the level of actual reality of something, (in The actual some sense) the more real the thing is. some Meditation #3 Descartes’s picture of levels of actual reality: Descartes (probably) would list the following things Descartes in increasing order of levels of reality: in Ideas Actual finite concrete things Infinite things Ideas, though fairly low on the reality level Ideas, ranking, can be about things higher up on the reality level ranking. reality The representative reality of an idea is equal to The representative the actual reality of the thing of which it is an idea. the How much representative reality an idea has is How just however much actual reality the thing it is an idea of would have if that thing existed. idea Meditation #3 So, though the actual reality of an idea will be rather So, actual low on the actual reality ranking, it can have a rather high representative reality if it is an idea of something representative that has lots of actual reality. that An idea of an idea will both have a very low actual reality An and a very low representative reality. and An idea of a table will have a very low actual reality and a An moderate level of representative reality. moderate An idea of God will have a very low actual reality, but will An have a very high level of representative reality. have Descartes says that his idea of God is an idea of Descartes something with the highest amount of actual reality-something namely, infinite actual reality. So the representative reality of his idea of God is So infinite. infinite. Meditation #3 But now recall Descartes’s principle: The Causal Adequacy Principle (CAP): The actual reality The ): of the cause of something must be equal to or greater than both the actual reality and the representative reality of that thing. thing. If Descartes’s idea of God has a cause and If CAP is true, then that cause must have infinite actual reality. infinite actual This is because the idea of God has infinite This representative reality and CAP says that a thing’s cause must have at least as much actual reality as both the thing’s actual reality and its and representative reality. representative Meditation #3 Now part II of the Trademark Argument Now again: again: 1. 2. 3. The amount of reality in the cause of my idea of God is The infinite. infinite. If the amount of reality in the cause of my idea of God If is infinite, then the cause of my idea of God is perfect. is The cause of my idea of God is perfect. 1,2 MP What’s the justification of premise 1? Part I of the Trademark Argument! Meditation #3 What, then, is the justification for premise 2 If the amount of reality in the cause of my idea of God is infinite, then the If cause of my idea of God is perfect cause supposed to be? If a thing has infinite actual reality, Descartes If reasons, then it lacks nothing. But as imperfection is a defect, i.e., a matter of lacking something, it must be that a thing that lacks nothing has no imperfections (no defects), and so must be perfect. (For a thing that lacks imperfections is perfect.) that Meditation #3 Finally, part III of the Trademark Argument Finally, again: again: 1. 2. 3. The cause of my idea of God is perfect. If the cause of my idea of God is perfect, then the If cause of my idea of God is God and not me. cause Therefore, the cause of my idea of God is God and not Therefore, me. me. 1,2 MP What is the justification for premise 1? Part II of the Trademark Argument! Meditation #3 What, then, is the justification for premise 2 What, If the cause of my idea of God is perfect, then the cause of my idea of God is God and not me. idea supposed to be? First, according to Descartes, God just is, as First, a matter of definition, the perfect being. matter And, second, as Descartes knows that he has And, imperfections--he makes mistakes, for example--he knows that he is not a perfect being. being. Meditation #3 Why is this argument called the Why Trademark Argument? Trademark “It is no surprise that God in creating me It should have placed this idea in me, to serve as a mark of the craftsman stamped on his work.” stamped Meditation #3 The Trademark Argument is valid. Each of its parts is valid, so it is valid as well. So, if the conclusion is false, what must be So, the case? the One of its premises must be false. What do you think of the Trademark What Argument? Argument? Is it sound? If not which premise is false? Meditation #3 The Cartesian Circle In his argument for the existence of God, many In critics have charged Descartes with arguing in a circle. circle. A person argues in a circle if she presents person argues an argument in which she relies on an antecedent commitment to the truth of her conclusion in supporting one of the premises of her argument. of Meditation #3 Arguing in a circle is bad because one Arguing presents arguments in an attempt to convince people who don’t already believe the conclusion of the argument to come to believe it. believe But if one argues in a circle one can’t get someone But who doesn’t already believe the conclusion to come to believe it because accepting one of the premises of the argument already requires her believing what the argument is trying to get her to believe. believe. Meditation #3 1. An example of arguing in a circle: The Bible says God exists. 2. If the Bible says God exists, then God If exists. exists. 3. Therefore, God exists. 1,2 MP Meditation #3 This argument argues in a circle, or begs the This question, because the only reason one could question because have for believing the second premise have If the Bible says God exists, then God exists. iis that one thinks that the Bible is the word of s God and whatever God says is true. God But if one already accepts this reason for believing But already the second premise to be true, then the argument for the conclusion that God exists is unnecessary. for And if one doesn’t already believe that God exists, And then one won’t accept this reason for believing the second premise of the argument and so one won’t have reason to think the argument is sound. have Meditation #3 How is Descartes alleged to have argued in a How circle in offering his Trademark Argument for the existence of God? existence says: says: At the very beginning of Meditation #3 Descartes At “I am certain that I am a thinking thing. Doesn’t that tell Doesn’t me what it takes for me to be certain about anything? In this first item of knowledge there is simply a vivid and clear perception of what I am asserting; this wouldn’t be enough to make me certain of its truth if it could ever turn out that something that I perceived so vividly and clearly was false. So I now seem to be able to lay it down as a general rule that whatever I perceive very vividly and clearly is true.” very Meditation #3 Descartes seems to derive from his knowledge that he Descartes exists and that he is a thinking thing, that the following principle holds: principle Vivid and Clear Perception Principle (VCPP): If I perceive something vividly and clearly to be true, then I can be certain that it is true. that But after laying down this principle, Descartes immediately But goes on to say that he can only be sure that it holds if there is no all powerful God who could deceive him even about what he vividly and clearly perceives to be true. about “Whenever I bring to mind my old belief in the supreme Whenever power of God. I have to admit that God could, if he wanted to, easily make me go wrong even about things that I perceive clearly…. I shall want to remove even this slight reason for doubt; so when I get the opportunity I shall examine whether there is a God, and (if there is) whether he canbe a deceiver. If I don’t settle this, it seems, then I can never be quite certain about anything else.” quite Meditation #3 So, as Descartes indicates in this passage, So, before he can trust VCCP, he must first prove VCCP he that there is no such all powerful deceiving God. God. that proof. that His Trademark Argument is supposed to be His In proving the existence of God as a perfect being, he In takes himself to prove that there is no deceiving God. takes If God is perfect, then God is not a deceiver--because If being a deceiver would be a moral imperfection. being Meditation #3 BUT, in offering his Trademark Argument he in appeals to certain principles on the grounds that he perceives them vividly and clearly to be true. be For instance, Descartes maintains that the Causal For Adequacy Principle is true because he perceives it vividly and clearly to be true. vividly “Now it is obvious by the natural light that the total Now cause of something must contain at least as much reality as does the effect.” reality Whenever Descartes says of something that it is obvious Whenever (or revealed) by the natural light he means that to be natural synonymous with saying that he perceives it vividly and clearly to be true. clearly Meditation #3 So in arguing for the existence of a perfect God, So in order that he can establish that there is no allin powerful deceiving God, he appeals to a powerful principle, VCCP, which he can’t be sure of unless VCCP which there is no such all-powerful deceiving God. there of an all-powerful deceiving God in order to legitimately appeal to VCCP in his argument for VCCP the non-existence of such a God. the Thus, he needs to presuppose the non-existence Thus, CIRCLE! ...
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