Posted: Dec 17, 2011 7:29 am
by jlowder
Ihavenofingerprints wrote:I'm not trained in probability. But surely if the "fine tuning of the universe" gives theism more credibility or 'likely-ness'. The simple fact that life probably exists elsewhere in the universe (according to almost all experts), and it is also likely that if life does exist, there are many alien civilizations more advanced than us. Also given how we know long distance space travel certainly isn't impossible with the right technology. The case for the presence of UFO's in our galaxy - that can find their way into our solar system - and eventually Earth by tracking radio waves most certainly rises above that of "santa" or "unicorns", and would undoubtedly give theism a run for it's money when it comes to credibility.

But we know UFO's aren't flying around earth and all the masses of people putting up a case for their existence shouldn't be taken seriously until they get some better evidence.

My worry is that I'd be lowering my standards if I started taking people like this seriously. Let alone people claiming the supernatural phenomena exists (it would be inconsistent for me to treat one group seriously but not another).

For the record, I don't think the evidence of so-called "fine-tuning" does increase the probability of theism. My earlier posts should not be interpreted as an endorsement of fine-tuning arguments; they should not even be interpreted as an endorsement of the fine-tuning argument I formulated. My point was simply that there are good ways and bad ways to refute the fine-tuning argument. It seems to me that the multiverse hypothesis is one of the bad ways: it is a fundamentally misguided objection.

So what would be a good way to refute fine-tuning arguments (notice this is plural, since there are many different versions)? Focus on the claim that fine-tuning is more likely on theism than on naturalism: challenge the proponent of the argument to meet their burden of proof and provide reasons or evidence in support of that claim. Simply saying that fine-tuning is improbable on naturalism, by itself, is evidentially worthless since it's possible that fine-tuning is equally or even more improbable on theism. So why should we believe that the explanatory hypothesis of theism "predicts" the evidence of fine-tuning? If someone can't give a good answer to that question, then they've failed to support that argument.

Consider this analogy. Let E be evidence that I bought lunch today at McDonald's; G be the hypothesis that the earth is the center of the solar system; and H be the hypothesis that the sun is the center of the solar system. H obviously gives no reason at all to expect that I would buy lunch today at McDonald's. In other words, H does not predict E, i.e., Pr(E|H) < 0.5. But so what? It doesn't follow that G is true or even that G is more likely than H. Why? Because G also fails to predict E, i.e., Pr(E|G) < 0.5. So there's no reason at all to think my buying lunch today at McDonald's is evidence favoring geocentrism over heliocentrism, i.e., Pr(E|G) > Pr(E|H).

Let's go back to fine-tuning. It may be the case that fine-tuning is just as irrelevant to theism and naturalism, just as my buying lunch today at McDonald's is irrelevant to geocentrism and heliocentrism. Proponents of fine-tuning arguments assert that fine-tuning is relevant, but they need to do more than assert that. They need to provide an argument.

Another problem with fine-tuning arguments for God is that they typically commit the fallacy of understated evidence. In the words of Paul Draper, "proponents of a theistic argument are guilty of this fallacy if they "successfully identify some general fact F about a topic X that is antecedently more likely on theism than on naturalism, but ignore other more specific facts about X, facts that, given F, are more likely on naturalism than on theism."[1]

So even if it is (were?) the case that fine-tuning is some evidence for theism, there are other more specific facts about fine-tuning which appear to be more likely on naturalism than on theism:

1. Our universe is not teeming with life, including life much more impressive than human life.
2. The only intelligent life we know of is human and it exists in this universe.
3. Intelligent life is the result of evolution.

See for further examples of this fallacy.