Tuesday, July 10, 2007

What is the "Fine Tuning" argument?

Some of the other guys on this blog have forgotten more biology than I've ever learned. I hope, though, that I can bring something else to this blog. I want to carry on some discussion of some of the logical arguments used in the intelligent design debate that I hope everyone can profit from.

Last post I talked a little about the "God of the gaps" fallacy, which isn't always as fallacious as materialists suggest. This time, I want to talk a little about "fine tuning". Here again, materialist apologists are misrepresenting what's being said - and missing the point.

Fine Tuning

Within what bounds is life possible? What are the ranges of values that various physical constants must exist within for us to exist? This is the "fine tuning" question. Let me borrow a few examples from another web site to give you an idea of some of the facts involved:

  • The electromagnetic coupling constant binds electrons to protons in atoms. If it was smaller, fewer electrons could be held. If it was larger, electrons would be held too tightly to bond with other atoms.~

  • Ratio of electron to proton mass (1:1836). Again, if this was larger or smaller, molecules could not form.

  • Carbon and oxygen nuclei have finely tuned energy levels.

  • Electromagnetic and gravitational forces are finely tuned, so the right kind of star can be stable.

  • Our sun is the right colour. If it was redder or bluer, photosynthetic response would be weaker.

  • Our sun is also the right mass. If it was larger, its brightness would change too quickly and there would be too much high energy radiation. If it was smaller, the range of planetary distances able to support life would be too narrow; the right distance would be so close to the star that tidal forces would disrupt the planet's rotational period. UV radiation would also be inadequate for photosynthesis.

  • The earth's distance from the sun is crucial for a stable water cycle. Too far away, and most water would freeze; too close and most water would boil.

  • The earth’s gravity, axial tilt, rotation period, magnetic field, crust thickness, oxygen/nitrogen ratio, carbon dioxide, water vapour and ozone levels are just right.


Impressive, is it not? The most memorable quote that sums the situation up is from eminent Cambridge physicist Fred Hoyle: he said that it appeared as if "a super-intellect has been monkeying with physics". The set-up seems rigged.

The question is, is this a valid argument? Many materialist apologists strongly argue that it isn't, and pour scorn on the fools who disagree. Here I include a quotation from blog of "the atheist experience", a "weekly live call-in television show sponsored by the Atheist Community of Austin." Here's what they think:

The whole assumption about fine tuning is a fallacy called affirming the consequent, or arguing from your conclusion. ... Douglas Adams goofed on this in a now-immortal passage in his Hitchhiker's Guide to the Galaxy series.

". . . imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!'"


I like the illustration - it makes the point very well. Because we are here, therefore we know that the right conditions for us to be here must exist, therefore the discovery that those conditions do in fact exist proves nothing. The probability of making this discovery is 100%. Ta-dah! Cue atheist victory lap.

Hang on a minute...

If you've been concentrating really hard, though, you may have noticed that Adams' objection makes a subtle switch in the calculation being made. Adams' illustration uses this calculation:

P ( the conditions exist for life | life exists)

i.e. "The probability that conditions are tuned for life, given than life exists". As the event space being considered is completely included within the event space that is given, the answer is certainty, and the calculation is not particularly useful. Life is known to exist, so calculations about its probability have no value. The interesting calculation is to look at how narrow the boundaries are for the various conditions that make life possible.

As scientists seek to discover the extent of these boundaries, the possible results have two extremes:

  1. There are very wide ranges of conditions within which life is possible.

  2. The range of conditions within which life is possible is very small.

If you've got that point, you'll see where Adams went wrong. The question isn't "is life possible?" - we know that the answer to that is "yes, with absolute certainty". The question is "was life very possible, or rather unlikely, or somewhere in between?".

Imagine that a man tosses a coin 500 times, and I call out "heads, tails, heads, heads, tails", etc., to give a sequence 500 guesses long. Suppose that after I do so, a man hands me a prize. What did I get the prize for? You don't know, so you do some investigating.

Suppose that I got given the prize for getting more than 50% of my guesses correct. That's not massively impressive, is it? But suppose rather that you discovered that the prize was only given to me because I got 100% of my guesses correct. That would be staggering. The chances of doing that are about 1 in 3 * 10^150 - an incredible number, beyond the number of atoms believed to exist in the universe.

If we keep in mind Adams' illustration, then Adams has said: "he's got the prize, so we know that he guessed up to the necessary standard - so it proves nothing". Actually, though, the question is to find out what room for error I had in order to get that prize. What we then find out is that "to get the prize was phenomenally unlikely - I suspect someone's monkeyed with the coin".

Looking More Closely At The Outcome

Look at those two extremes for the outcome again. The first is that scientists might discover that there is a broad range of circumstances within which life would be possible. What would this prove? Would it indicate that life arose by chance?

In fact, it would prove nothing. A wide range allows both that life might have arisen by chance, or might not - you have to look elsewhere to find out which. If I score a tap-in in a game of soccer, I might be a soccer genius; or I might not; you'll never know - the evidence can't decide.

On the other hand, if scientists discover that the range within which life is possible is extremely small, then this is positive evidence for intelligent design. The point is not that the system is fine-tuned (as in Adams' mistake); the point is that the fine tuning was absolutely necessary. If I take ten free-kicks in soccer from long distance and curl them all into the top corner, then the thesis that "David can't play soccer" takes a severe beating. (I can always dream!).

The signficance of this is that the "fine tuning" argument is valid, puddles notwithstanding. The discovery that life requires extreme fine-tuning is a highly significant piece of evidence. Science is turning up more and more evidence that our world is intelligently designed.

David Anderson



At 11:19 AM, Blogger William Bradford said...

Good post David. A welcome addition to the mostly biology based posts we see here.


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