So, (he said conversationally), this video, courtesy of Pharyngula, got me thinking about a popular apologist argument of late - one that even showed up in the most recent Discover magazine (this being the International Year of Astronomy) - that of Fine Tuning.
For the unfamiliar, I will elucidate. Fine Tuning is a universal variant of the Argument from Design. Rather than looking inward (the "I sure didn't evolve from a monkey!" crowd), the groups that posit fine tuning look outward. Look at the universe, they say. If there had been a trifle less matter at the beginning, the matter/antimatter imbalance wouldn't have worked out in our favour. Look at the density of matter and the Cosmological Constant. If those were even a trifle different from how they are, the universe would never have lasted long enough for life to form.
On a more local scale, look at the solar system and our place in it. If there weren't gas giants to scoop up most of the incoming interstellar debris, Earth could've been pulverized by an asteroid long ago. If Earth weren't the precise distance from the sun that it is, it would've been too hot or too cold. If Earth's moon weren't in the orbit it is, there would never have been the tidal pools that life needed to get out of the oceans, or, conversely, the tides would've been catastrophically intense - in either case, no tidal pools. If Earth's gravity weren't exactly what it is, the earth might have lost its atmosphere. And so on, and so forth. I'm sure, thinking about it, you can come up with hundreds of stellar and universal constants without which life as we know it could never have come to be.
Now, some apologists find this particularly enticing, and it may seem a more moderate view than most, simply because it presupposes that a great deal of astronomy is, in fact, accurate, and that geological "Deep" time is a fact, rather than, as the YECs would have us believe, a hypothesis. Don't be fooled - this is just Paley's tired old argument, dressed up in fancy new clothes. How can [object] come to have been, when it is so [intricate/beautiful/sensitive to change]? Surely there must have been an intelligence behind its design!
Now, the Watchmaker concept has been thoroughly debunked, but this latest variant on Paley's postulate hasn't been around long enough to get its own book as yet. However, it has a number of arguments against it - one of which is a bit of a knockout.
First, there is a counterargument against those who might argue that a benign creator designed the universe for life (or for some creators, especially for Human life) - they did a really, really poor job of it.
Look at every other planet in the solar system. Look at any of the hundred nearest stars. Look, for that matter, at the vacuum of space. None of these are capable of supporting life. Look, for that matter, at our own planet. While unicellular life is found just about everywhere, the polar extremes sure as heck don't support much of anything - and if your opponent is arguing in favour of a human-centric deity, more than three-quarters of the planet is not very conducive to human life.
In this argument, much depends on the postulated creator being omnipotent. If your opponent in such a debate is willing to grant that the postulated creator was neither omnipotent nor omniscient, or, alternately, that they were either non-benevolent or actively malevolent, then the problem of incompetence (that is, for someone tuning the universe to favour life, they did an awful job) doesn't come up. Now, the question arises as to exactly how much they could have to do with things like the Cosmological Constant if they don't have omnipotence on their side... but I digress.
Regardless, both the Tuning argument and its major opposing arguments spring from the same source - the Anthropic Principle. (The universe we are in is capable of sustaining intelligent life at least at one location in space/time. Us, if you were wondering.)
To the theist, the answer to "Why is this the case?" is very simple. God made the universe with the intent that we might live in it.
However, there are a number of more plausible explanations - and a few that are slightly less plausible but still more feasible in Occam's eyes than "God did it".
The first is comprised of four sub-clauses, but the final point of each is this: if a universe exists/existed where the conditions were not conducive to the emergence of intelligent life, no one would be around to ask the question. That we are guarantees that the universe in which we ask it has these properties. Ah, say the theists, but how?
Well, the simplest answer is coincidence. Yes, a stunning display of coincidences, but if they hadn't occurred, we'd never know about it, since life (including the questioning folks) would never have arisen. So, say the proponents of coincidence, we're here, so it did happen. Q.E.D.
A second group, with a few more followers than the first, suggest that part of the Theory of Everything that we've not yet encountered includes strictures on the laws of physics such that if a universe exists, various constants must be the way they are, or that all the constants are dependent on some other variable (possibly discrete), which forces them into their current values. Therefore, if a universe exists, and isn't radically different from ours, it would have to have laws, topology, and constants similar to our own. This argument is given limited credence, as it is, as yet, only a hypothesis, with little evidence to support it.
A third group uses the multiverse theory to suggest that there are, in fact, googols of other universes which DO have different constants, or different distributions of matter, and so forth. If everything that can happen must happen, it is then a certainty, rather than a possibility, that in at least one universe, life must arise. In fact, since there are many ways life could have arisen without intelligent life, or without any one creature, an infinite number of universes must have life, by this argument. Recent developments in quantum physics - particularly quantum computing - lend credence to this argument. It also suggests interesting things about human thought, as decisions might very well simply be bifurcations between new universes in the multiverse, with what you perceive to be "yourself" progressing down a particular branch of the tree.
The fourth and final group suggests that while there is only one universe at any given time, it has repeatedly appeared and collapsed, been and then not-been, on a sort of quasi-timescale (as linear time cannot exist outside the bounds of the physical universe). After however many quadrillion iterations, the chance of the universe having the features necessary to engender life becomes more than reasonable. In a way, this is like the multiverse theory, in that as the number of iterations approaches infinity, the chance of a universe coming into being that can support/engender life approaches one.
There is one other, more recent explanation for the principle, but this one is both a bit more out-of-left-field and a bit more difficult to wrap one's head around. (At least my own head. Those with more capacious heads might find it simple. In any event, read on.)
This last group postulates that life, and intelligence, is in fact necessary to allow the universe to exist. As has been demonstrated in quantum physics, the act of observation changes the observed. Known as the Participatory Anthropic Principle, a simplification of this point of view would be that the universe itself can be interpreted to act like a Schrodinger waveform, and unless or until life arises to act as the observer, it takes on all possible properties. This, in a way, is similar to the multiverse theory, in that if the universe takes on all possible properties, it is a given that life will arise.
In summary - while both "how" and "why" are nebulous at the moment, (and in fact, the "why" may never be more satisfactorily answered than "because"), the argument for Fine Tuning by an intelligence is far less plausible than any of those offered by the Anthropic Principle. It's just Paley's Watch meeting the God of the Gaps.