Help Wanted – Part 1

For the past two years I have, in my copious free time, been studying Richard Swinburne’s case for God. Recently my focus has been on his evaluation of the cosmological argument (hereafter TCA) in his book The Existence of God, 2nd edition (hereafter EOG). His version of TCA is quite simple:

e: A complex physical universe exists.
Therefore
g: God exists.

But Swinburne’s argument about TCA is not so simple.

Swinburne does not present TCA as a proof of the existence of God, nor does he claim that TCA makes God’s existence probable. Rather, he claims that e makes g more probable that it would be otherwise:

P(gle & k) > P(glk)

Where k is tautological (a priori) background knowledge. In other words, e provides relevant evidence in support of of the hypothesis g, increasing the probability that g is the case.

I understand most of Swinburne’s argument in support of his claim about TCA, but there is a part of his reasoning that I just don’t get, and I’m hoping that someone can help me to get it.

There are two key premises in Swinburne’s argument about TCA:
(TCA8) The probability that there will be a complex physical universe given that God exists is at least ½. (EOG, p.151)

(TCA9) The probability that there will be a complex physical universe given that God does not exist is low. (EOG, p.151)

I fully understand Swinburne’s argument for (TCA8), and I think I understand his core argument for (TCA9), but I’m having difficulty figuring out his reasoning in support of a premise used to support (TCA9). Here is how I would translate (TCA9) into a conditional probability statement:

.2 ≤ P(el~g&k) < .4

(I’m interpreting ‘low probability’ as meaning ‘greater than or equal to .2, and less than .4′).Here is what I believe to be the core argument for (TCA9):
(TCA14) The probability that a complex physical universe exists without an explanation is very low. (EOG, p.152)
(TCA15) The probability that a complex physical universe exists given that God does not exist is approximately equal to the probability that a complex physical universe exists without an explanation. (EOG, p.149)
Therefore:
(TCA13) The probability that a complex physical universe exists given that God does not exist is approximately a very low probability.
Therefore:
(TCA9) The probability that there will be a complex physical universe given that God does not exist is low (at most). (EOG, p.151)


I think I understand Swinburne’s reasoning in support of (TCA14), but I cannot figure out his reasoning in support of (TCA15), even after reading and re-reading what he says in support of this claim.

I’m also uncertain about how to represent (TCA14) in terms of a conditional probability statement. Here is my attempt to do so:

0 < P(el~y&k) < .2

y: e has an explanation.

If I knew how to correctly represent (TCA14) in a conditional probability statement, perhaps that would help me to understand Swinburne’s thinking.

Swinburne eliminates the possibility that science might explain e, which leaves him with just two possibilities: either e has a personal explanation (e being the result of a choice of some person for some purpose) or else e has no explanation at all, and is just a brute fact.


Traditionally, cosmological arguments eliminate the possibility that the universe is simply a brute fact by an appeal to the Principle of Sufficient Reason (hereafter: PSR). But Swinburne rejects the strong version of PSR, and sees no good reason for accepting a weaker version of PSR. So, what he does is argue that the a priori probability of e being the case but having no explanation is very low, (TCA14).

About Bradley Bowen
  • http://www.blogger.com/profile/05130016615104653729 TaiChi

    Hi Bradley,

    Yes, I don't think there's much more to it than what you've just said. The strong PSR states that every event has an explanation; the weak PSR states that every event has a possible explanation; and here, Swinburne's 'probabilistic' PSR just states that the probability of some event's not having an explanation is very low. So I think you can read Swinburne as reasoning on the usual sorts of theistic intuitions about an event's being explicable somehow being the natural, typical way of things, but refraining from going so far as to endorse the notion that an explanation might be required.

    BTW, I wanted to point you (or was it Keith?) to a paper I found on fine-tuning which is excellent. Roughly, it argues that the existence of fine-tuning is evidence against the God hypothesis, because whilst the God hypothesis is consistent with the observation of life-permitting and non-life permitting constants*, Naturalism is only consistent with the observation of life-permitting constants, i.e. fine-tuning. Observation therefore must favor Naturalism over Theism, given that Naturalism has passed an evidential test, whereas Theism hasn't been tested by these observations at all. Here it is:

    http://www.talkreason.org/articles/super.cfm

    * Think here of scientist's measuring the physical constants and being astounded to find that life could not naturally have arisen in the universe.

  • http://www.blogger.com/profile/05034037930336299849 Mike Gage

    I wonder what on Earth this could mean to call the universe complex. Complex compared to what? The laws are seemingly simple and they seem to bring about what we call complexities.

    I also wonder how this fares alongside a multiverse hypothesis. If the multiverse is true, then one might say it's inscrutable how complex the non-local parts of it really are. In that case, we would also have an explanation for our own universe – colliding membranes or something – that did not rely ona God.

  • http://www.blogger.com/profile/05211466026535549638 Bradley Bowen

    Mike Gage said…
    I wonder what on Earth this could mean to call the universe complex. Complex compared to what?
    ===============
    Response:
    Swinburne's description of the actual universe suggests what he has in mind (although the premise of CTA is an abstraction: 'a complex physical universe').

    "A complex physical universe…is indeed a rather complex thing. We need to look at our universe and meditate about it, and the complexity should be apparent. There are lots and lots of separate chunks of it. The chunks each have different finite and not very natural volume, shape, mass, etc. –consider the vast diversity of the galaxies, stars, and planets, and pebbles on the seashore….There is just a certain finite amount [of matter], or at any rate finite density of it, manifested in the particular bits; and a certain finite amount, or at any rate finite density of energy, momentum, spin, etc." (EOG, 2nd ed., p.150)

  • http://www.blogger.com/profile/05211466026535549638 Bradley Bowen

    I asked Mr. Swinburne to clarify his reasoning on this point, and he kindly provided a detailed explanation:

    *Let c be 'there is a personal creator other than God'. Then (given the sentence on p.149, 'e could not, as we have seen..'), with k as a mere tautology, P (e &~h&~c&k;) will be the probability that a complex physical universe exists without an explanation. By the calculus this equals P(e|~h&~c&k;) P(~h&~c&k;). I have argued that c is much less probable than h. If (see p.109) P(h|k) is very low, P(c|k) will be even lower. In that case P(~h&~c&k;) will be close to 1, and so P (e&~h&~c&k;) will equal approx P(e|~h&~c&k;) which – given the very high probability of ~c approx equals P(e|~h&k;) ,which is the probability that there will be a physical universe given that God does not exist. If however P(h|k)were not very low, then the equation would not hold, but I was trying to give the atheist as much as I could, and so assuming that it is very unlikely a priori that there is a God. But if the prior probability of God is higher, then the arguments from e or anything else won't have so much force, but then they wouldn't need to in order to reach the same posterior probability. I am sorry that my presentation on p.149 seems to have been a bit sloppy, but – I hope that you will agree – it doesn't make much difference to the result. Thanks for your interest – Richard

    (email dated 10/24/11)

  • http://www.blogger.com/profile/05034037930336299849 Mike Gage

    Bradley, Swinburne's description still seems odd to me. Here are a few thoughts:

    "There are lots and lots of separate chunks of it.The chunks each have different finite and not very natural volume, shape, mass, etc. –consider the vast diversity of the galaxies, stars, and planets, and pebbles on the seashore"

    Well, yes and no. That's clearly a matter of perspective. Consider picking up a plain white paper plate. Would you define it as complex? Probably not, yet, from the right perspective it would appear more complex. It is not completely uniform – there are patterns with greater densities of particles with certain spin etc. But from a far back perspective it doesn't seem complex at all. It looks pretty uniform. But, of course, so does our universe from the right perspective.

    It seems like any charge of complexity would have to be leveled at the initial conditions and the laws. I think that if you know those pieces of information, then you can predict what will happen with the matter, like particles, stars, etc. This takes away any charge of complexity since they just stem from the aforementioned things. It seems like those things would have to be complex for the charge to have any weight.

    Of course, who can really say whether the initial conditions (which we don't really know) or the laws (which we don't really understand) are complex? I would still be tempted to ask 'comples compared to what?'.

  • http://www.blogger.com/profile/05211466026535549638 Bradley Bowen

    Mike Gage said…

    It seems like any charge of complexity would have to be leveled at the initial conditions and the laws. I think that if you know those pieces of information, then you can predict what will happen with the matter, like particles, stars, etc. This takes away any charge of complexity since they just stem from the aforementioned things. It seems like those things would have to be complex for the charge to have any weight.
    ===========
    Response:

    Good point.

    In the case of animal life, the complexity we see is explained in terms of very simple forms of life evolving into more complex forms over billions of years.

    So, conceivably, the universe was at one point in time simpler, and it 'evolved' over time into the complex universe we see today.

    Swinburne is aware of this line of thought, and discusses it briefly in EOG, 2nd ed., p.150.


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