Robert Oerter’s Fine-Tuning Argument for Naturalism

Robert Oerter has written an interesting post on his blog outlining what he calls a fine-tuning argument for naturalism. It’s important to keep in mind that Oerter doesn’t actually believe that this argument is a good argument for naturalism. Rather, he thinks it’s useful for showing what’s wrong with the fine-tuning argument for theism.

Rather than try to summarize his argument, I invite readers to simply read it for themselves.

What follows is a comment I left at Oerter’s site.

You write:

Remember that God is, by hypothesis, omnipotent. That means that God could have caused life to arise by miraculous means, even in a universe that was not fine-tuned.

Let us define ML as the hypothesis that God miraculously allows life to arise in a universe that is not fine-tuned.

Both ML and its denial (~ML) are logically compatible with theism. So I think the best way to evaluate the evidential significance of ML is to treat ML as an auxiliary hypothesis and apply the theorem of total probability.

Pr(FTU | T & K & L) = Pr(ML | T) x Pr(FTU | ML & T & K & L) + Pr(~ML | T) x Pr(FTU | ~ML & T & K & L)

What that formula shows is that, in order for the fine-tuning argument for naturalism to work, Pr(ML | T) must be greater than Pr(~ML | T). But it is far from obvious that that is the case. So what reason is there to suppose that Pr(ML | T) > Pr(~ML | T)?

ETA: And if Pr(ML | T) < Pr(~ML | T), then it’s no longer clear how this argument is supposed to show what’s wrong with the theistic fine-tuning argument.

Apologetics Infographic #1: Atheism and Nothingness
G&T Rebuttal, Part 6: Chapter 7
Joel Steinmetz: The Problem of Intentionality: A Cardinal Difficulty for Physicalism (2005)
Christian Apologist: Theists Care About Science but Naturalists Don’t
About Jeffery Jay Lowder

Jeffery Jay Lowder is President Emeritus of Internet Infidels, Inc., which he co-founded in 1995. He is also co-editor of the book, The Empty Tomb: Jesus Beyond the Grave.

  • Bradley Bowen

    God, as conceived of in Christianity and Islam and Judaism, is omnipotent and omniscient. So, if God had wanted to create plants, animals, and human beings in just six days, as in the book of Genesis, God could have done so. Performing such miracles of creation in a universe that was NOT fine tuned would have given us human beings some signficant evidence for the existence of God. In other words, God could have left us good evidence in support of ‘scientific creationism’.

    On the other hand, if the physcial laws of the universe were established by God billions of years ago precisely in order to favor the evolution of life on a few planets in a few galaxies over a period of billions of years, and if life arose as a result of the normal operation of physical laws over a period of billions of years, then the orgin of life can be explained simply in terms of the normal operation of physcial laws, and thus we are left with much weaker evidence (if it is evidence at all) for the existence of God.

    Christians and Jews (and I believe Muslims too) believe that God sometimes reveals himself through miracles. So, from a Christian or Jewish point of view not only is a literal Genesis creation possible, it is probable even apart from the book of Genesis, because it seems more likely that a God who wishes to reveal himself to human beings and who sometimes does so through miracles, would clearly prefer to bring about plants, animals, and human beings by means of instantaneous creation ex nihilo in a universe that was NOT fine tuned (thus providing some good evidence of his existence and character) rather than to set up a bunch of physical laws and non-living physical objects that would over a period of billions of years of normal operaton eventuallly produce plants, animals, and human beings.

    A God who works purely through the laws of physics and non-living physical objects to bring about living things and humans appears to be a God who wishes to remain unknown to human beings, and thus to be a deceptive person, and certainly would be a person much different from the God of miracles put forward by Christians, Jews, and Muslims.

  • Ron

    Pr(FT/naturalism+we exist) is not 100%. A coarse tuned universe is also compatible with naturalism. Indeed, a theist would say a coarse tuned universe is better predicted by naturalism, even if we include our existence in our background knowledge. So its not clear that Pr(FT/naturalism+we exist)>Pr(FT/theism+we exist) for the reason given by Oerter.

    • Jeffery Jay Lowder

      How do you define “fine-tuned universe” and “coarse-tuned universe”?

      • Ron

        Fine tuned = narrow life permitting range. Coarse tuned = wide life permitting range.

        • Jeffery Jay Lowder

          Why should we believe Pr(course tuned | naturalism & we exist) > Pr(fine tuned | naturalism & we exist)?

          • Ron

            I personally dont think we should (I dont think the FTA is any good). But I would expect a theist to say coarse tuning would be less surprising on naturalism, since coarse tuning entails that there are many alternative universes we could have lived in — under coarse tuning we wouldnt need to think of our existence as “lucky.”

            My main point was that naturalism is equally compatible with coarse tuning, so Pr(ft/naturalism+we exist) isnt 1.

  • Rob

    Isn’t it the case that the theistic fine tuning argument doesn’t work if Pr(ML | T)=Pr(~ML | T)?