Thursday, 20 July 2017

Turning Fine-Tuning on its Head

The existence of you and m e is, in a sense, fine-tuned.  This statement might come as a surprise to anyone who has noticed that I am vehemently against the fine-tuning argument, but I can explain.  The fine-tuning argument goes a little like this:

Therefore, god.

I've stripped it down a bit, but those are the basics of the argument.  I don't have much against the first line, but I do have problems with the second as I would have problems with the first premise of an expanded fine-tuning argument, namely the assertion "If fine-tuning then god".  The stripped-down deluxe version of the argument, which I also have problems with, is:

If there is fine-tuning, then either god or something else,
Not something else,
Therefore, god.

My problem is with the third line of this version.  When argued by such luminaries as WLC the main thrust is that the idea that we should be here purely by chance, when the odds against are so staggeringly high, beggars belief.  The problem is that there remains a gap between unlikely and impossible.  The answer "something else" remains possible, and to some it is believable despite being unlikely, while the god solution is simply not believable. 

What I don't argue against is the line "Fine-tuning", so long as that line is short-hand for "if things were slightly different in this universe, then intelligent life would almost certainly not exist".  If "fine-tuning" is short-hand for "this universe was designed by a divine being of some sort", then of course I have a problem but then the whole fine-tuning argument resolves down to begging the question, "god, therefore god".

Now, about you and me being fine-tuned - let's get all excited about it!  Think about how amazing it is that we exist on one little planet in such a massive universe.  What are the chances of that?  If we go by volume, we can see that the Earth is only about 10-56 of the observable universe's volume.  If we were just about anywhere else, we'd be dead. 

But of course it'd be silly to compare our location with a random spot in intergalactic or even interstellar space.  It's pretty cold out there, and we need to be a bit warmer than that, without being too warm.  So we could consider how remarkable it is that we are in orbit around just this star, one that is so suitable for intelligent life to develop.  While our sun is one of about 1021 stars, it's a pretty common type of star - roughly one in five is a G-class star.  And about one in five of those is estimated to have an "Earth-like" planet in orbit around it - in the habitable zone.  So about one in twenty-five stars are of the right type with the right type of planet in orbit around it.

Not that amazing after all.  Although, to get the one in twenty-five figure we are assuming that once we've got the right type of star, and it's got the right sort of planet in the right sort of zone, then we get that one automatically.  That's a little unreasonable.  Our solar system is jam-packed with planets, moons, asteroids and comets (by which I mean generally "very sparsely packed, but with more than half a million objects").   The chances of ending up on the one habitable object out of all of those is about, well, one in half a million (after we've select the right star, with the right planet in orbit around it). 

If we did limit ourselves to a suitable planet in orbit around a suitable star though, the fact is that we are on a very privileged part of that planet - standing somewhere close to the surface (ISS residents aside, plus anyone currently on a high-altitude international flight).  We're sitting or standing rather comfortably on the surface instead of floating high in the atmosphere, floundering at the bottom of an ocean or being crushed and then burnt to a cinder in the core.  And we live in a community that is relatively well placed on that surface: not in a volcano crater, not in Death Valley, not in Antarctica, not just below the summit of Everest.  What great fortune!  However, only about one sixth of the Earth's surface is habitable (half of the land mass).

Then there is timing.  This is a rather good time for intelligent life.  The planet that we are on has sufficient oxygen, not too much carbon dioxide, it still retains enough of the ozone layer that we don't die too quickly of cancer and the temperature is about right - not too cold that we freeze to death and not too warm that we are constantly flayed by killer storms or reduced to desiccated husks.  We have flowering plants, most importantly variations of grass that permit large populations to feed themselves, and they have only been around for about 55 million years, so 1.4% of the time that the Earth has been a planet.  Humans (as Homo sapiens) have only been around for about 200,000 years, or one thousandth of one per cent of the age of the Earth.  Genetic research indicates that humanity has gone through a few bottlenecks, the most recent may have been about 70,000 years ago - meaning that we were lucky, as a species, to not go extinct at that time.

It's remarkable that we're alive at all.  It's in the order of one in a billion, even aside from all the unlikeliness of one particular human meeting another particular human and producing a specific human at a specific time (with none of them being killed by any of the lethal flora and fauna that is abundant on this planet).  So … sure, we're fine-tuned, in a sense.


The thing is that what I have just provided is a continuous stream of indicators that our universe is not finely tuned for human life.  Our planet is not finely tuned for human life – there’s a very narrow band geologically and temporally.  We are finely tuned to exist in that very narrow band and the fine-tuned-ness of a biological organism to its environment is far more elegantly explained by evolution than it is by the introduction of a creator being.

The bottom line is that fine-tuning is not a challenge to naturalism or evolution or atheism, the real challenge is to the creationist or intelligent design theorist to explain why the universe is so unrelentingly hostile to humanity.

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