PHIL 236 Philosophy of Religion

1. PHIL 236 Philosophy of Religion The Design Argument

2. The Argument from Design • Also known as the teleological argument • Is inductive • Aims to make God’s existence probable • Sometimes it is also “abductive”, i.e. God’s existence is the best explanation. • Is a posteriori • Is based not on pure reasoning (is not a priori) but on observable facts

3. Versions of the argument • Two common versions • One appeals to biological facts • Paley’s version of design argument • Intelligent Design Movements • The other appeals to cosmological facts • Fine-Tuning Argument • Both see evidence of design in nature

4. William Paley’s ArgumentThe Watch and the Human Eye • In a nutshell: • Artificial mechanisms like watches must have designers • By analogy, so must organs like the eye

5. The Starting Point • If you found a stone, you might not infer that it had a maker • If you found a watch, you would infer that it had a maker • Why? • Unlike the stone, the parts of the watch clearly fit together to serve a purpose.

6. Things you Wouldn’t Say • The watch might always have been there • The watch’s parts came together by chance • The watch merely exhibits “metallic nature” • Matter has to take some form; why not a watch? • Useless parts prove the lack of a maker • We don’t know enough to infer a designer

7. The Self-Reproducing Watch • Suppose the watch could reproduce itself • Would we say it had no maker? Paley says NO! • First, this would make the watch even more remarkable • Second, even if this watch had a “parent” that had a “parent”... The series “wouldn’t tend to a limit”; • Each watch would still need to be explained

8. Paley’s Analogy • The human eye is even more remarkable than the watch • Its parts obviously fit together to serve a purpose • Reasoning by analogy: like the watch, the eye must have had a designer and maker

9. A Dated Argument? • Biologist (and passionate atheist) Richard Dawkins says that in its day, the argument from design would have been entirely convincing • Why? Because no good natural explanation for the biological facts was available. • Dawkins believes that this is no longer so

10. Paley vs. Darwin William Paley 1743-1805 Charles Darwin 1809-1882

11. Evolution and Design • Without evolution, design seems to be the only available explanation for the eye. • Evolution undercuts Paley's argument by providing a plausible rival explanation for the same facts • Note: the point is not that evolution is known to be true. The point is that it undermines the claim that divine design is the only plausible explanation

12. A Mere Theory? • People often say: Evolution is “only a theory” • This is a misunderstanding of what scientists mean by “theory.” • A theory is a set of organizing principles that provides a way of unifying and explaining a body of facts. • Calling something a theory says nothing at all about whether it is probable • It’s not contradictory to say that a theory can be known to be correct

13. Resistance to Evolution • In the USA, there is a high degree of resistance to accepting evolution. Why? • Plausible answer: people believe that they need to choose between evolution and their religious beliefs • We should ask: is this a false dilemma?

14. Two Reasons • Here are two reasons for thinking the dilemma is false: • 1) The dilemma assumes that religious belief calls for reading all scripture literally. But many deeply religious people (the Pope, for example) disagree. • 2) The dilemma sees evolution as a view that denies the possibility of divine intervention. But that claim is beyond the scope of science.

15. Intelligent Design • Intelligent design theory offers an update to Paley’s argument • It tries to show that some biological facts can’t be explained by evolution • This may be true. The question is: do the arguments of ID theorists show this?

16. Irreducible Complexity • Michael Behe says: a system is irreducibly complex if removing any part would make it non-functional • Behe argues: evolution can’t produce irreducibly complex systems • The reason: unless the system were fully assembled, there would be nothing for selection to operate on

17. The Example • Bacterial flagella work like an outboard motor • Remove any part, says Behe, and the flagellum doesn’t work. • Therefore, Behe says, evolution couldn’t produce it

18. The Scientist’s Reply • The function a "part" has now need not be the function it had earlier in evolutionary history. • Selection can "co-opt" parts and systems that function one way in one context and use them in another for a different purpose • Therefore, “irreducible complexity” doesn’t rule out evolution

19. ...Continued • The point is not that evolutionary biology has explained the flagellum • (though Kenneth Miller argues that we have many parts of a good explanation) • The point is that a good understanding of how explanations work in evolutionary theory doesn’t rule out an evolutionary explanation

20. More Generally... • Nature is worthy of wonder, but... • ID is a "God of the Gaps“ approach, and • Biologists may come up with plausible accounts of ID examples. • Many people (including theologians and scientists) believe that evolution and theism can co-exist.

21. Interim Summary • Paley’s argument has a serious rival in evolution, but • Even if evolution is true, this doesn’t show that God played no role in evolution. • ID theorists may be correct in believing that there is a designer, but • The kinds of arguments they offer are open to scientific criticism

22. Fine-tuning Design Arguments • So far, we have looked at biological design arguments • These arguments focus on apparent design in organs and organisms • Another important kind of argument concentrates on large-scale facts about the universe • These arguments are called fine-tuning arguments.

23. Robin Collins’s Analogy • Suppose we discovered a planet where there was • A domed structure • With an oxygen-recycling system • Ideal temperature and humidity range for life • Water-recycling systems • Food production systems

24. Collins’s Point • We would not agree that this system was a product of chance • We would see it as a product of intelligence, but • a) Earth itself is such a system, and • b) More generally, various feature of the universe are fine-tuned for life

25. Examples of Fine-Tuning: Gravity • Gravity: if the gravitational constant were only a little stronger, mammals our size would be crushed. Stronger yet and all stars would be red dwarfs – not warm enough to support life • If gravity were a little weaker, all stars would be blue giants – they don’t exist long enough for life to develop

26. Another Example: Strong Nuclear Force • This force keeps atoms together by resisting electric repulsion. • A 1% increase would lead to almost all carbon being burned into oxygen; a 2% increase would prevent protons – and hence atoms – from forming • A 5% decrease would mean a universe with no molecule more complex than hydrogen

27. The Cosmological Constant • This is the energy density of empty space • This constant is very close to zero • If it were even slightly larger, the universe would expand far too rapidly for stars, galaxies, planets and hence life to form

28. The Point Again • The constants of the universe seem to make the universe into an “irreducibly complex system” from the point of view of life • That is: tamper even a little with even one of the many fine-tuned constants, and there would be no life

29. Probability • The point can be put in probability terms: given the range of values open “a priori” to the constants, it is fantastically improbable that by chance alone, they would permit life • However, if an intelligent designer is responsible for their values, the fine-tuning is no longer improbable.

30. Objection: Other Life-Forms • The fine-tuning argument points to various physical conditions necessary for life, but • It doesn’t take account of the fact that our form of carbon-based life may not be the only possible form

31. Reply: • For the most part, the fine-tuning argument doesn’t focus on the details of life-forms (e.g., carbon vs. silicon) • Instead it focuses on such things as the possibility of atoms of any sort, or of stars that can provide energy, or of the possibility of chemical processes

32. Objection: “Fundamental Law” • Perhaps there is a fundamental law that • underlies more specific physical laws, and • Implies that the constants have the values that they have • If so, the fine-tuning would be explained by reference to this fundamental law

33. Replies • First, the hypothesis is sheer speculation • (However, the objector might reply that it represents a coherent possibility – just as God does) • Second, it would just allow a new version of the question. We could ask: why this fundamental law, rather than some other? • Why a fundamental law that calls for these values of the constants?

34. Further to the second reply • John Leslie points out that our scientific models allow for other sorts of universes with other sorts ranges of constants. • Therefore, there is no good reason to believe in such a fundamental law

35. Objection: The universe had to be some way • The universe had to have some set of laws • Further, there’s no reason to think any one detailed set more improbable than any other. • Looked at in this way, there is nothing to explain

36. A Comparison • Suppose we consider a bridge hand. The chance of someone being dealt that particular, specific bridge hand is very small • However, we don’t think there’s any need to explain why someone got this bridge hand as opposed to any other equally improbable hand

37. Reply • If we carry this reasoning to its limit, then nothing requires explanation. • This is because every situation, if considered in enough detail, is improbable • For example: the precise arrangement of the mess on my desk is improbable, but calls for no explanation. • But if the papers were stacked so that they formed a series of arches, that would require explanation

38. Continued • Some values for constants would seem merely “random” or uninteresting – not in need of explanation • The fine-tuning arguer says: the constants of our universe aren’t like that. They fit together too remarkably when looked at from the point of view of life • Hence, they need to be explained.

39. Objection: the Anthropic Principle • The (weak) anthropic principle says that the laws of the universe are “restricted” by the conditions necessary for their being observed • Translation: we couldn’t know that the constants are what they are unless those constants were consistent with the existence of observers • Supposed conclusion: we shouldn’t be surprised to find that the constants permit life

40. Reply • Of course we couldn’t observe constants that ruled out our existence, but • The constants could still be improbable • If we had discovered that a wide range of constants was compatible with life, the fine-tuning argument couldn’t get off the ground • What is surprising is that the constants came out right even though “right” is such a narrow range.

41. Compare (John Leslie's Example) • Suppose that five minutes ago, I was blindfolded and fired at by 100 marksmen with loaded rifles. • I couldn’t observe that I’m still alive unless all the marksmen missed • However: it’s still surprising that I’m alive, and calls for explanation

42. Objection: Many Universes • Some physicists have posited theories that imply the existence of many “sub-universes” with differing laws and constants • If enough such universes exist, with enough variety, it wouldn’t be surprising that one or more permitted life

43. Compare: • If you toss a coin 10 times in a row and get 10 heads, you will be surprised. • But if 1,000,000 people each toss a coin 10 times, then it would be surprising if no one got 10 heads in a row. (The chances of 10 heads in a row are 1 in 1024 for one tosser.)

44. Reply • If the many-universes hypothesis is true, it would provide an alternate explanation for “fine-tuning” • But there isn’t any empirical evidence for many universes, and the theoretical arguments are very controversial

45. Still... • If the theoreticians can make the many-universe view respectable (show that it fits well with other pats of physics, is elegant, could explain a great deal...) then it would be a legitimate rival to fine-tuning theistic explanations • Compare: we said earlier that evolution does most of its work against Paley by providing a legitimate rival view • We would then need to decide which view is overall more likely

46. And Still Further... • That is something people could disagree about. • Therefore: if many universes are a good theoretical idea, that doesn’t mean that theistic design is a bad idea • It means instead that we have more than one viable hypothesis

47. A Larger Issue: Who Designed the Designer? • David Hume (1711-1776) asks: • Isn’t God as remarkable as the things God is supposed to explain? • If so, doesn’t this call for positing a designer for God? • If so, don’t we set forth on an infinite regress?

48. Mechanism vs. Magic • Ordinary designers assemble parts in familiar ways • Do we have any idea how God assembled the world? If not, does the design argument explain anything?

49. In Short... • If there is a supernatural designer, this being is as remarkable as the human eye (not to mention the bacterial flagellum!) • Consequently, it's not clear that positing a Divine Designer explains much. It may just postpone the problem. • But... should religion be in the business of giving “scientific” explanations?

50. More Generally... • Wars between science and religion are unfortunate • They are unfortunate for science if they put science in the position of addressing questions outside its purview • They are unfortunate for religion if they turn religion into a quasi-scientific hypothesis that science can slowly chip away at