Fine Tuning and Retrospective Probabilities

The fine tuning argument for the existence of God is based on the observation that there are numerous physical parameters (the mass and charge of a proton, the gravitational constant, matter-antimatter asymmetry, etc.) which appear “finely tuned” to produce a universe capable of harboring life. What fine tuning effectively shows is that, given random chance, it seems astronomically improbable that these parameters would align in such a way as to produce a universe with galaxies, stars, planets, and life.

I recently asked 23 atheists how they account for fine tuning (question #3 in the survey). Several respondents made a point that I found interesting, and wanted to address. They compared fine tuning to “winning the lottery”, and our own existence to that of “lottery winners”. For the lottery winner, the odds against winning the lottery are meaningless in retrospect…because he’s obviously already won. Thus, probability arguments like fine-tuning are worthless, because they can’t be applied to events that have already been actualized. One respondent put it this way:

“The term ‘finely tuned’ is an anthropomorphic spin on ‘it just is the way it is’. If things were any different we wouldn’t be here to ask the question. We have the power of hindsight and from our point of view, can see what looks like impossible odds of our existence. However, with any possibility of it being the way it is, no matter how small the chance is, then it’s possible. And since we are here to ask the question, the possibility was obviously realized, no matter the odds.”

The problem with this “lottery objection” is that it discounts alternative explanations, and assumes that we MUST have overcome these astronomical probabilities. But that puts the cart before the horse by presupposing a naturalistic explanation.

Imagine that your buddy Joe shows up to work one day, and starts throwing stacks of hundred dollar bills at everyone he sees. You know he’s not a rich guy, so clearly he recently acquired a huge sum of money. It’s possible that Joe just won the lottery (because even though the odds of winning are small, someone obviously has to win). Yet it’s also possible that Joe stole the money, or received it as a gift, or inherited it from a relative, or found it in a suitcase next to a dead guy in the middle of the desert.

Seems legit.

Hopefully you see where I’m going with this. The point is that none of us can really “know” with empirical certainty exactly how our life-permitting universe got here. The statistical improbability of fine tuning can’t be waved off as “inevitable good luck” unless one has already ruled out the alternative explanation to “luck”. So the fine tuning argument is effective because it (indirectly) lends credence to this “alternative explanation”: that these fundamental physical constants were intentionally and intelligently set by a Fine Tuner.


5 thoughts on “Fine Tuning and Retrospective Probabilities

  1. Great post (and I agree with you completely). Your post inspired me to ask a
    question: Are atheists (and possibly some theists as well) missing an (some) important epistemelogical step(s)? I think they are not asking some version of the following question:
    By what authority or reason are we logically allowed to invoke chance? What are the mathematical and scientific grounds for reducing all of the patterns, structures and systems to chance? If we do this, how can we claim causality and induction, which are integral to science and reasoning in general? Saying “just chance” is not how they got to the incredible understanding of atoms and the universe we have today. Linnaeus did not randomly classify plants; he observed and organized according to patterns. An archaeologist is not permitted to say Linear A happened by chance, just because we cannot decipher it yet (or some similar monument). If we applied Aristotle’s four causes to the universe in general, it seems to me that we would have to admit that not only is there a material cause (atoms, energy, dark matter, etc) and a formal cause (gravity, relativity, entropy, stars, planets, life), but also an efficient cause (God, a creator, something) and a final cause (a teleological view; what is this universe for?). The problem is that science will likely ignore these last two causes (except when it comes to evolution; DNA is very teleological). Thus, the issue is that science has abandoned metaphysics, just as some theists have abandoned it for fundamentalism. Without metaphysics, I don’t see faith & science reconciling. Thanks for a great post; God bless you. Would love to hear your comments.

    • Great to hear from you again! You raise some terrific points. The initial questions you pose immediately bring to mind Alvin Plantinga’s evolutionary argument against naturalism.

      Also, while not entirely related, I think one might ask, “why, on atheism, is truth-seeking intrinsically good?” Neil Shenvi fleshes the question out a little more thoroughly in this essay:

  2. Actually, using the analogy of the probability of the retrospective lottery win is a perfectly sound response to the question – how do you explain fine tuning, because it exposes how silly the question is.

    Another answer that does exactly the same:
    Life in the universe is analogous in this case to a puddle in a pothole.
    You don’t look at the shape of a pothole and, observing how it absolutely perfectly accommodates the puddle, conclude that it was “fine tuned” to do so.
    Now consider why.
    Firstly, the pothole came before the puddle.
    Secondly, the puddle is shaped by the the pothole.

    So why do people try to do it with life in the universe?

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