Cosmological Argument for Existence of God

1. Cosmological Argument for Existence of God Is Big Bang Cosmology of Relevance?

2. Cosmological Arguments • One form tries to show that the series of causes can’t go back to infinity • Aquinas’s First and Second Way • Kalam Cosmological Argument (Craig) • Another form tries to show that at least some being must exist necessarily • Aquinas’s Third way • appeal to a “principle of sufficient reason”, which holds that everything can be explained

3. Aquinas’s Five Ways • The classical cosmological arguments come from St. Thomas Aquinas’s Five Ways. • The first three are usually called cosmological arguments. • Arguments one and two aim to show that infinite series of causes are impossible • Argument three tries to prove the existence of a necessary being.

4. The First and Second Ways • The first and second ways have a very similar structure. We will consider only the second in detail • The first way deals with change – the word is sometimes given as “motion.” • It argues that all change must have a cause, and that the series of causes can’t go back to infinity.

5. Continued • The second way deals with “efficient causes.” • We will take this to mean: causes that sustain things in being – “sustaining causes.” • It may be that the sun (which provides energy to the earth) is a sustaining cause of your existence. • It may be as well that electromagnetic forces are sustaining causes of you

6. The Second Way Stated • Aquinas’s Second Way: • Some things are caused (sustained) by other things, which are caused by other things... • Nothing is the cause of itself • To take away the cause is to take away the effect. • If there is no first cause, there will be no intermediate causes and hence no immediate causes of what’s here and how. • But what’s here and now has causes. • Therefore, there is a first cause: God.

7. In Plainer English • Aquinas notes that many things (all things?) that we see around us are kept in being by other causes. • Some of these causes have their own sustaining causes. • He goes on to claim that chains of sustaining causes can’t stretch back to infinity

8. What Kind of Argument? • Aquinas’s argument is a posteriori in one sense: it starts with observable facts • The proof proceeds by reductio ad absurdum • In other words, Aquinas tries to show that if we believe in infinite series of causes, we end up in contradiction

9. The Contradiction • Aquinas assumes plausibly: to take away the cause is to take away the effect • If the sustaining causes of what we see around us didn’t exist, neither would those things • If we take away the first cause, he says, we take away all the things that depend on it • This implies that things we know to exist don’t exist: contradiction

10. The Problem • To say there’s no first cause isn’t to “take away” any cause. • It’s just to say: every cause has a cause in turn • That may be puzzling, but... • Aquinas hasn’t proved that it’s impossible to have an infinite series of causes

11. A More Sophisticated Version • Aquinas doesn’t seem to have shown that infinite series of sustaining causes are impossible • William Lane Craig might argue: Aquinas made a mistake in allowing that the bare idea of an infinite series of actual things is possible • Craig argues that “actual infinities” are themselves impossible • His argument (based on an older Islamic argument) is called the Kalam Cosmological Argument

12. A Diagram of Craig’s Argument

13. In Words: • Craig considers several alternatives • Either the universe had a beginning or it didn’t. He argues that it did. • He argues this because assuming otherwise means assuming an actual infinity of past events • He believes this is impossible • We will consider this in detail, but first...

14. The Kalam Argument Continued • Suppose the universe had a beginning • Craig says: the beginning was either caused or uncaused • He repudiates the second alternative; he thinks it’s absurd • Finally, he argues that the cause must have been personal: it was God

15. Three Problems • We will see that • 1) Craig doesn’t succeed in showing that an infinite series of causes is absurd • 2) He doesn’t show that an uncaused universe is absurd • 3) And although his remarks about a personal cause are suggestive, they aren’t a proof

16. *The Heart of the Argument • The core of Craig’s argument is the “proof” that there can’t be an actual infinite series of causes. • Some may think that talk of infinity is inherently confused or absurd • Craig does not go this far. • He accepts the mathematical theory of infinity.

17. *Mathematics and Infinity • We first need to ask: when to two sets have the same number of things? • The mathematician’s answer: when their members can be paired one-one: • {a,b,c,d,e} • {v,w,x,y,z} vs • {a,b,c,d,e,f} • {v,w,x,y,z}

18. *Infinity • We can compare infinite collections in this way. This implies: the number of counting numbers equals the number of even numbers: • 1 2 3 4 5 6 7 8 9 10... • 2 4 6 8 10 12 14 16 18 20...

19. Continued • Note what mathematicians mean here • The phrase “same number” originally did not apply to infinite collections • Mathematicians found a way to extend the definition: to use the phrase consistently in a new context • The new use agrees with the old use, but extends that use

20. *Craig and Infinity • Craig agrees that the mathematical theory of infinity is consistent • He agrees that we can say things like • The number of even numbers equals the number of counting numbers • The number of counting numbers is less than the number of real numbers • He believes that we get absurdities only when we talk of concrete infinities

21. *Absurdities? • Craig brings up an example from the mathematician Cantor • Imagine an infinite bookshelf with books alternating black, red, black, red, black... • Now imagine borrowing all the red books • How many books are left? Answer: the same number as there were originally • Craig says: this is clearly absurd

22. *A Reply • The claim that there are just as many books left may sound absurd. However, • All it means is that there is a one-one function pairing the total set of books with the set of black books • Craig’s admission that the mathematical theory is consistent requires him to agree that this is consistent

23. *Further... • We can still make sense of our feeling that there are “fewer” books left. • We simply need to speak carefully. • It is still true that the remaining books are a proper subset of the original collection • This captures an important sense in which the set of remaining books is "smaller"

24. *A Worse Absurdity? • Craig continues: suppose all the red books have been removed. We can fill in all the gaps in the shelf with the remaining books • How? Move the 2nd black book to where the first red book was. • Then move the 3rd black book to where the 2nd black book was • And so on and so on and so on • The result: all the gaps are filled • Craig’s judgment: this is absurd

25. *What Kind of Absurdity? • There is no contradiction in what has been described. It is mathematically consistent. • It is certainly surprising and puzzling. • However, a good deal of what we have learned from modern science is surprising and puzzling • This is different from saying it is absurd

26. *Furthermore • We may think that we could never fill in the gaps this way, and • This may be perfectly true. • (It might require infinite time and infinite energy) • However, the idea that an omnipotent God couldn’t do it is much less clear

27. *The Kalam Argument and Omnipotence • Craig’s argument contains a theological danger • It appears to rule out the possibility of God doing things that on the face of it seem possible for divine being • For example: couldn’t pick out a straight line in space, and put a stone every mile along the line? • If not, why not? Is this really absurd?

28. *Absurdity Again • If we can show that something is internally contradictory (a square circle, e.g.), it is absurd • Craig hasn’t shown that • If we can show that something contradicts a known fact, we have an absurdity • Craig hasn’t done that either. • Therefore, the first step of Craig’s argument is at best highly inconclusive

29. Recap • Aquinas’s First and Second Ways try to prove that certain kinds of infinite causal chains are impossible • The arguments seem weak: either confusing denying a first cause with taking away a cause or simply assuming what needs to be proved • Craig tries to prove that actual infinities are absurd • All he succeeds in showing is that they would have some surprising properties

30. Craig Continued • Suppose we agree with Craig that the universe has a beginning • We can ask: does the rest of his argument work? • Does he show that the beginning must have been caused? • Does he show that the cause must have been personal?

31. The First Cause • Craig seems to think that if the beginning of the universe wasn’t caused, then the universe must simply have “popped into existence” • He thinks that no reasonable person would accept this • There is a problem with this way of putting things

32. The Beginning of Time • If the universe “popped into existence,” that would suggest a time before the appearance of matter • This ignores a different possibility: there is no time “before” the beginning of the physical universe • The universe could be nothing more than the sum total of the events and objects it contains

33. A Personal Creator? • Suppose we agree that it’s plausible that the beginning of the physical universe had a cause • Something Craig doesn’t stress: that cause couldn’t be physical. • Why not? Because if it were physical, it would simply be another part of the universe, and Craig would say that it needs a cause

34. Continued... • If the beginning of the universe has a cause, it must be something that it not physical • Plausibly, this also means something not in time. • (Why? Because things in time are arguably physical, though this is controversial) • Therefore, plausibly, the cause of the universe would have to be eternal – outside time

35. Eternal Cause? • Craig asks: if the cause is eternal, why wouldn’t the effect be eternal too? • Craig’s answer: we can make sense of this if we assume that God eternally intended to create a universe in time

36. Necessary Beings • So far, we have considered arguments to show that there can’t be an infinite series of events or causes • Another important kind of cosmological argument tries to show that there must be at least one necessary being – a being that couldn’t’ fail to exist • This being, it is argued, is God

37. Aquinas’s Cosmological Argument • Some things begin and end (we’ll call them evanescent things) • If everything was evanescent, there would have been a time when nothing existed • If there was a time when nothing existed, nothing would exist now. • Since that’s false, there’s something (God!) that isn’t evanescent

38. An Obvious Problem • Suppose everything is evanescent. • Just because each thing was non-existent at some time doesn’t mean that at some one time each thing was non-existent • Compare: everyone has a mother. But no one person is everyone’s mother.

39. In short... • Aquinas’s argument doesn’t show that there must be a necessary being. • Still, the intuition Aquinas starts with is interesting: if every single thing is contingent, it’s remarkable that anything exists. • To explore this idea, we need a different approach

40. A Deeper Principle • Leibniz (1646-1716) said: • No fact can be real or existent, no statement true, unless there be a sufficient reason why it is so and not otherwise. • This is the Principle of Sufficient Reason (PSR) • In short: everything has an explanation

41. A Problem with the Principle • Some things don’t seem likely to have sufficient reasons • For example: suppose that no one at this moment is exactly 5 feet 10.37821 inches tall • That precise fact (a negative fact) may have no sufficient reason

42. A Restatement of the Principle • William Rowe suggests revising the principle: • Every thing and every positive fact has a sufficient reason • This avoids the problem described above • (Note: Rowe still ends up rejecting the PSR)

43. What is a Sufficient Reason? • A sufficient reason must explain whatever it’s intended to be a reason for • That means that it must imply what it’s a reason for: if X explains Y, then Y follows from X; it’s impossible for X to be true and Y false. • Further, in the case where Y is contingent, X can’t just be Y restated.

44. Comment on Previous Slide • Some things (necessary truths – e.g., 2+3=5) may be "self-explaining" • Contingent truths – things that might not have been so – can't be self-explaining • (If you suspect otherwise, try to find a good example of a self-explaining contingent truth) • So if Yis contingent, and X just restates Y, X can't be the sufficient reason for Y

45. A Principle • To evaluate the PSR, we need to understand another principle: the Transfer of Necessity • This principle is a matter of logic. It says: • If X is a necessary truth (i.e., couldn’t be false no matter what) and X implies Y, then Y is also necessary.

46. Why? • Suppose X is necessary, X implies Y and Y is contingent. • In that case, we can imagine a case where Y is false. But since X is necessary, X would be true in that case • Since X implies Y, Y would have to be both true and false in that case – which is absurd.

47. Put another way... • If X is necessary, and X implies Y, then it’s impossible for Y to be false. • If Ywere false, then the principle we just described would imply that X is false. • That can’t happen if X is necessary • Thus, necessary truths only imply other necessary truths

48. Problems for the PSR • Consider the collection of all positive contingent truths. This is itself a contingent truth, which we’ll call F • Suppose R is a sufficient reason for F. Then R can’t be a necessary truth (because necessary truths don’t imply contingent truths.

49. Continued • Suppose that R is contingent (the only other alternative). Then • R can’t be a mere “part” of F because in that case it won’t imply F • R can’t be identical to F because then R won’t explain F • R can’t be a negative (or partly negative) fact, because it’s obscure how a negative fact could explain a positive fact

50. Putting it another way... • If R is necessary, then R doesn’t imply the contingent truth F • If R is contingent, then R itself needs a sufficient reason, and circularity or regress threatens. • Therefore, whether R is necessary or contingent, R can’t be the sufficient reason for F