麻省理工大学：《语言学与哲学》课程教学资源（英文讲义）fa01lec01.pdf_大学文库

24.00: Problems of Philosophy Prof. Sally Haslanger September 10, 2001 The Ontological Argument The Question (and framework for answers) Does God exist? (We will be assuming a philosophical/theological conception of God as a perfect beingthis god's perfections include: omnipotence, omniscience, and perfect goodness.) Theist: Yes, God exists. rational theism: There is a rational basis (sound reasons) for belief in God arational theism/fideism: There is no rational basis (sound reasons) for belief in God, but believe anyway (without reasons). irrational theism: There is a rational basis (sound reasons) for believing that God doesn't exist, but believe in God anyway (contrary to reasons). Atheist: No, God doesn't exist. Agnostic: Don't know (or: doesn't believe either that God exists or doesn't exist.). Arguments for God's Existence Rational Theism seeks to provide arguments for the existence of God, e.g., Cosmological Argument: Everything is either a dependent being or an independent (self-existent/self-caused) being; not everything is dependent; so, something (=God) is independent (self-existent/self-caused). Teleological Argument/Argument from Design: The best explanation of the world's order and systematicity is the hypothesis that it was designed by a perfect designer; so there is a perfect designer (=God) responsible for the world. Ontological Argument: our focus todayÖ Ontological Argument One of the distinctive features of the ontological argument is that it attempts to prove the existence of God simply from the concept of God. In other words, you don't need to go searching about for God in the world; simply knowing what God is supposed to be, i.e., simply having the concept and seeing its implications, should be enough to demonstrate that God exists. So what is the concept of God we're using? God =df an absolutely perfect being, i.e., a being than which nothing greater is possible, a being than which nothing greater can even be conceived

Let's grant this concept of God ( for the moment). Now you might still think that to answer whether God exists, we should get clearer on what we mean by exists. First, let's note the difference between existing in reality and existing"in the understanding or"in the mind". Here are some examples Existent &nbs p; Non-existent The Charles river &nb sp; The Fountain of Youth &nb sp; Unicorns Boston &nbs p Atlantis George W. Bush &nbs p; Sherlock Holmes Obviously, the issue before us is not whether God exists in the mind. whether some people have an idea of God. Many people do(or seem to). The question is whether the concept they have--the idea that they associate with the term"God"--is eal in the world external to the mind Philosophers such as Anselm and Descartes have reasoned that just as we can argue that there are things that necessarily donit exist, we can show that there are some things that necessarily exist. It is plausible that some concepts necessarily don' t have instances because the concept is self-contradictory A squircle=df a square circle Argument for the non-existence of squircles 1)The concept of a squircle is a concept of a figure that is both square and circular 2) Something square and circular cannot possibly exist 3)The concept of a squircle is a concept of something that cannot possibly exist 4)Therefore, (necessarily)no squircles exist But are there also concepts that necessarily have instances? The suggestion before us is that the concept of God is such a In order to follow the reasoning we need to consider the idea that existence is a perfection. What does this mean? Consider a fictional character, eg, Sherlock Holmes. Sherlock Holmes, is imperfect. He's imperfect in many ways(e.g, he smokes, he is impatient, can be arrogant, etc. ) But one of his imperfections, it seems, is that he doesn ' t exist! The claim seems to be that any merely possible(non-actual)object would be more perfect if it existed So Sherlock Holmes is not perfect, in part because he doesnit really exist, but only exists in stories So, putting these ideas together, here is one version of the ontological argument 1)The concept of God is the concept of an absolutely perfect being, i.e., that than which nothing greater is possible 2)Existence is a perfection, i.e., a" great making"property: it is greater to exist than not to exist 3)Because existence is a perfection, i.e., a" great making"property, if God didn,'t exist in reality(but only in the understanding), then it would be possible for there to be something even greater than God,i.e with all of God s qualities plus existence. But this is impossible, given the definition of God 4)So the concept of God is the concept of an existent being 5)Therefore, God exists Objections. 1. The perfect Island For Anselm there is only one thing whose essence includes existence, and that is God. But where is this restriction coming

Let's grant this concept of God (for the moment). Now you might still think that to answer whether God exists, we should get clearer on what we mean by exists. First, let's note the difference between existing in reality and existing "in the understanding" or "in the mind". Here are some examples: Existent: &nbs p; Non-existent: The Charles River &nb sp; The Fountain of Youth Chipmonks & nbsp; &nb sp; Unicorns Boston &nbs p; Atlantis George W. Bush &nbs p; Sherlock Holmes Obviously, the issue before us is not whether God exists in the mind...whether some people have an idea of God. Many people do (or seem to). The question is whether the concept they have--the idea that they associate with the term "God"--is real in the world external to the mind. Philosophers such as Anselm and Descartes have reasoned that just as we can argue that there are things that necessarily donít exist, we can show that there are some things that necessarily exist. It is plausible that some concepts necessarily don't have instances because the concept is self-contradictory: A squircle =df a square circle. Argument for the non-existence of squircles: 1) The concept of a squircle is a concept of a figure that is both square and circular. 2) Something square and circular cannot possibly exist. 3) The concept of a squircle is a concept of something that cannot possibly exist. 4) Therefore, (necessarily) no squircles exist. But are there also concepts that necessarily have instances? The suggestion before us is that the concept of God is such a concept. In order to follow the reasoning we need to consider the idea that existence is a perfection. What does this mean? Consider a fictional character, eg., Sherlock Holmes. Sherlock Holmes, is imperfect. He's imperfect in many ways (e.g., he smokes, he is impatient, can be arrogant, etc.). But one of his imperfections, it seems, is that he doesn't exist! The claim seems to be that any merely possible (non-actual) object would be more perfect if it existed. So Sherlock Holmes is not perfect, in part because he doesnít really exist, but only exists in stories. So, putting these ideas together, here is one version of the ontological argument: 1) The concept of God is the concept of an absolutely perfect being, i.e., that than which nothing greater is possible. 2) Existence is a perfection, i.e., a "great making" property: it is greater to exist than not to exist. 3) Because existence is a perfection, i.e., a "great making" property, if God didn't exist in reality (but only in the understanding), then it would be possible for there to be something even greater than God, i.e., with all of God's qualities plus existence. But this is impossible, given the definition of God. 4) So the concept of God is the concept of an existent being. 5) Therefore, God exists. Objections: 1. The Perfect Island For Anselm there is only one thing whose essence includes existence, and that is God. But where is this restriction coming

from? Why canit there be other things whose essences have this marvelous feature? and why canit we then prove these other things to exist just as Anselm has proved God to exist? Note that the same form of argument can be offered in support of the existence of a perfect island. Suppose X is a superisle iff x is an absolutely perfect island If you substitute'superisle'for'God' in the argument above, it should show that there exists a superisle. But there is no superisle So something must be wrong with the argument 2. Can't define things into existence The inference from(4)-(5)is problematic. Premise(4)is ambiguous and might mean either of two things (4a)To satisfy the God-concept you have to exist (4b) Some existing thing satisfies the God-concept Consider a different example A realunicorn=df an existing unicorn. a non-existing unicorn Now contrast RU4a) To satisfy the realunicorn-concept you have to exist. (True!) RU4b) Some existing thing satisfies the realunicorn-concept.(False!) From the fact that a realunicorn is defined as an existing unicorn, it doesnit follow that there are any. That is, to satisfy the realunicorn-concept you must exist, but it doesnit follow that anything satisfies the realunicorn-concept Of these, itis(4b) that we need to reach the conclusion (5)that God exists. but it seems itis( 4a)that follows from(1-3 Note: (1) basically says that the concept can only be satisfied by a perfect being, and(2-3)add that such a being will have to exist; so putting them together we get the result (4a)that to satisfy the concept you have to exist. Trouble is, there is no clear way of getting from(4a)to(4b ). However, the squircle argument is different. We can get from the equivalent of (4a) to(4b) (S4a) To satisfy the Squircle-concept you must not exist (S4b)No existing thing satisfies the Squircle-concept 3. Existence is not a property For several reasons(mentioned in lecture), many philosophers have concluded that existence is not a property of objects Rather, to say something exists is to say that a concept of that sort of thing has instances. If this is correct, then premise(2) is problematic. It isn't clear how to apply the idea that existence is a perfection to God. Should we say that the concept of God would be more perfect if God exists? But no one has suggested that the concept of God is perfect Conclusion You'll note that Rowe seems to think that some of the arguments are stronger than I do. E. g. he tries to defend Anselm against the"perfect island"argument, and against the charge that existence is not a property. I think that Rowe is mistaken

from? Why canít there be other things whose essences have this marvelous feature? And why canít we then prove these other things to exist just as Anselm has proved God to exist? Note that the same form of argument can be offered in support of the existence of a perfect island. Suppose: X is a superisle iff x is an absolutely perfect island. If you substitute 'superisle' for 'God' in the argument above, it should show that there exists a superisle. But there is no superisle. So something must be wrong with the argument. 2. Can't define things into existence. The inference from (4) - (5) is problematic. Premise (4) is ambiguous and might mean either of two things: (4a) To satisfy the God-concept you have to exist. (4b) Some existing thing satisfies the God-concept. Consider a different example: A realunicorn =df an existing unicorn. An ununicorn =df a non-existing unicorn. Now contrast: RU4a) To satisfy the realunicorn-concept you have to exist. (True!) RU4b) Some existing thing satisfies the realunicorn-concept. (False!) From the fact that a realunicorn is defined as an existing unicorn, it doesnít follow that there are any. That is, to satisfy the realunicorn-concept you must exist, but it doesnít follow that anything satisfies the realunicorn-concept. Of these, itís (4b) that we need to reach the conclusion (5) that God exists. But it seems itís (4a) that follows from (1-3). Note: (1) basically says that the concept can only be satisfied by a perfect being, and (2-3) add that such a being will have to exist; so putting them together we get the result (4a) that to satisfy the concept you have to exist. Trouble is, there is no clear way of getting from (4a) to (4b). However, the squircle argument is different. We can get from the equivalent of (4a) to (4b): (S4a) To satisfy the Squircle-concept you must not exist. (S4b) No existing thing satisfies the Squircle-concept. 3. Existence is not a property. For several reasons (mentioned in lecture), many philosophers have concluded that existence is not a property of objects. Rather, to say something exists is to say that a concept of that sort of thing has instances. If this is correct, then premise (2) is problematic. It isn't clear how to apply the idea that existence is a perfection to God. Should we say that the concept of God would be more perfect if God exists? But no one has suggested that the concept of God is perfect. Conclusion You'll note that Rowe seems to think that some of the arguments are stronger than I do. E.g., he tries to defend Anselm against the "perfect island" argument, and against the charge that existence is not a property. I think that Rowe is mistaken