PHLA10F 7. Necessary Being

Transcription

1 Necessary Being

2 A Priori and A Posteriori Truths Some truths (a priori) can be known simply by use of concepts and without any particular experience or observation (a posteriori) Examples: all bachelors are unmarried, 1725x235 = 405,375, the sum of the angles of a (Euclidean) triangle is 180, if Fred weighs more than Nancy, then Nancy weighs less than Fred, Red is a color, etc. A Priori truths and existence Some a priori truths entail existence There is a prime number between 50 and 55 Are there any non-mathematical examples? How do a priori existence claims affect the question: why is there something rather than nothing An a priori existence claim might answer that question

3 A Priori and A Posteriori Truths Two Distinctions A Priori / A Posteriori Necessary / Contingent Necessary Contingent A Priori = 6 I exist. A Posteriori?? Water = H 2 O Saturn has 56 moons.

4 The Ontological Argument God is that greater than which none can be conceived (God has maximal possible perfection). Suppose that God did not exist. Then one could imagine a being greater than God, namely something exactly like God but which DID exist Therefore, God exists. St. Anselm ( )

5 The Ontological Argument First premise: God is possible. Note this is an objective claim It is not a claim about what we can conceive or imagine We can conceive or imagine what is not possible Example: traveling faster than light Example: squaring the circle Grades of possibility Logical Metaphysical Nomological Epistemological What is the guide to possibility?

6 The Ontological Argument Second Premise: existence is a kind of perfection. Gaunilo s counter-example: The perfect island must exist If it did not, we could conceive of one more perfect, which is impossible Are the two arguments really the same in structure? Kant s classic reply: Existence is not a perfection/property Properties hold or do not hold of existing things Existence is the pre-condition for having properties, not a property itself Is that conclusive? The fact that all things exist does not show that existence is not a property I. Kant ( )

7 The Ontological Argument Sober s criticism A definition gives a condition for something counting as that sort of thing If part of the definition of a bachelor is being unmarried then all we can infer is that if a bachelor exists then he well be unmarried So even if existence is in the concept of God, that only shows that if God exists, then He exists. That is trivial and does not prove anything.

8 The Ontological Argument A Possible Worlds Version God is a necessary being. It is POSSIBLE that God exists. Therefore, in some possible world God exists. In that world, a necessary being exists. But a necessary being exists in ALL possible worlds. Therefore, that being exists in every world. Therefore, that being God exists in the actual world. Or in terms of statements. Possible(Necessary(God exists). So in some world Necessary(God exists). But then in ALL worlds (God exists). Therefore in the actual world (God exists).

9 The Ontological Argument Problems for the possible worlds version Is God possible? We proved a necessary being exists why must it be God? More particularly where is the proof that God (conceived of as personal, omni-b/o/p) is a necessary being. Is necessary existence a perfection? What about Sober s criticism Necessary existence characterizes God (by definition) but that only shows the if God exists then He exists necessarily This does not engage the possible worlds argument.

10 The Ontological Argument A possible analogy: Consider the claim it is possible that there is a prime number between and If it s true then there is a world where there is such a prime number Numbers are necessary beings, so this prime number exists in all worlds So this prime number exists in the actual world The question then comes down to is this number really possible (it turns out, no it is not possible there is no such prime number) So does the question come down to whether God is really possible?

11 Verification of God Theories of meaning What is it that makes words and sentences meaningful? Positivists divided all statements into two classes Analytic Synthetic Analytic statements are true or false because of their concepts Synthetic statements are true or false because of verifying experiences There is a close link between the synthetic/analytic distinction and the a posteriori/a priori distinction A. J. Ayer ( )

12 Verification of God The match between these concepts is shown by the empty boxes. Question: are there any significant analytic truths? Analytic Synthetic A Priori Bachelors are unmarried.????? A Posteriori???? Ottawa is the capital of Canada.

13 Verification of God According to the positivists, every statement is (in principle) decidable. Either via understanding the concepts in the statement This might be very hard (e.g. Mathematics) Or we need to observe nature This might be very hard There must be some experience which, if one had it, would raise or lower the probability of the statement Some statements are unverifiable (in principle) and so are meaningless. Examples: The world was created 5 minutes ago exactly as it was 5 minutes ago (notice: negation of meaningless is meaningless?) There are totally undetectable entities in the world Everything doubled in size one minute ago (?)

14 Verification of God But why should one be a verificationist? Do not confuse positivism with the need for science to make observable predictions Is the positivist principle verifiable? Is it analytic? Is it not plausible that there could be features of the world that are undetectable and unknowable? Let P be an unknown fact (there are lots). It is unknowable that P is unknowable. If you knew P was an unknowable fact, you would know P. Thus it would stop being unknown. Wolfgang Pauli ( ) I ve done a terrible thing today, something which no theoretical physicist should ever do. I have suggested something that can never be verified experimentally.

15 Verification of God The design argument suggests some auxiliary hypotheses which make God exists falsifiable or verifiable. Possible example: Since God is perfect, He will only make perfectly designed things there will be no imperfect adaptations in nature. There are imperfect adaptations however. Is God exists falsified? Theodicy is the task of explaining why the apparent evidence against God exists is not really good evidence. ( defense is just showing God is not ruled out...) New auxiliary hypotheses can be introduced. What is wrong with this one: if God exists, then everything in the world will be exactly as we observe it?