This universe we belong to has been organized into the homiest possible arrangement. And that extends beyond the wildflower bouquets that complement your living room décor beautifully. The laws that govern the universe are fine-tuned in the most impossibly precise manner to make life possible.
Let's take a glimpse at this. From essay The Dawkins Confusion by Alvin Plantinga, we are told:
"[I]f the force of gravity were only slightly stronger, all stars would be blue giants; if even slightly weaker, all would be red dwarves; in neither case could life have developed. The same goes for the weak and strong nuclear forces; if either had been even slightly different, life, at any rate life of the sort we have, could probably not have developed. Equally interesting in this connection is the so-called flatness problem: the existence of life also seems to depend very delicately upon the rate at which the universe is expanding." (Plantinga, 2007, 4)
The philosopher then quotes Stephen Hawking writing that, in the Big Bang model, during the Planck time (10-43 seconds after the Big Bang), had the ratio between explosive expansion and gravitational contraction been off by a degree of one in ten to the sixtieth power, life would be impossible.
The Big Bang model has to do with historical science, but of course observational science has this problem as well. The atom, for example, is made up of tiny charged particles known as protons (positive charge) and electrons (negative charge); they balance each other perfectly to the farthest degree we are capable of measuring. We know, in addition, that were the charges of protons and electrons not matched to at least a billionth of a degree, atoms would be unstable and life would be impossible.
That's a rather slim margin of error. It would appear that the chances of getting the precise universe we live in, with all the precise laws and forces that govern it, to the incredibly exact degree at which they exist, is a ridiculously improbable occurrence.
This fine-tuning argument has not, however, gone unnoticed by the community of Naturalists. How do they believe such a remarkable universe originated in the absence of a creator? The latest theory proposed has been the multiverse theory.
This idea states, in essence, that our universe is not the only universe in existence. There are, in fact (or more accurately, there could be), billions, trillions, even an almost infinite amount of universes in existence, each with their own laws, big bang expansion rates, and physical constants! Given such an enormous amount of universes, it is quite probable that one of them came about with the precise design we observe in ours today.
That's a very clever argument. Given the fact that it's entirely impossible to prove, it is nothing but an ad hoc explanation, an unscientific and religious answer from a group of people who claim to be scientific and unreligious. But looking at it from a statistical viewpoint, this rebuttal is not really that clever at all.
Take a trip with me to the casino. (Don't worry; I'm on a first-name-basis with the manager. He won't mind that you're underage.) The first thing I do is take you to the roulette wheel. For simplicity's sake we'll assume the numbers on it range from 1 to 37. We sit down beside it and watch one sucker after another bet all their winnings on their own lucky numbers. After this goes on for half an hour, I give you a wink. All this time has passed, I whisper, and not once has the number 4 been hit! I take out my wallet and persuade you to do the same. We'll bet all our money on 4 and split the rewards! The number 4 is due to come up on the next spin - we'll be millionaires!
This kind of thinking describes what is called the Gambler's Fallacy. It is certainly not a likely occurrence to never get a four after spinning the wheel after, say, three hundred times. However, if I do spin the wheel three hundred times, all without getting that four, what are the chances of getting a four on my 301st spin?
My chance is still 1 out of 37.
To put it another way, it would be a remarkable occurrence if I flipped a coin twenty times and received all heads; this past phenomenon does not change the fact that the next coin flip will yield a 50\% chance of getting tails and a 50\% chance of getting heads. Past results do not change present probabilities.
Let's go back to the fine-tuning counterargument, that there are billions and trillions of universes, so at least one of them must be like ours. We'll say, now, that there were a trillion big bangs before our Big Bang occurred, each resulting in a trillion other universes. Now our own universe comes about; what are the chances that our Big Bang will result in the universe we have today?
The chances are still as ridiculously improbable as they were when there was only one universe.
So you see, the problem remains. No matter how many multiverses a scientist invokes, there is still the problem of our universe. It is incredibly perfectly well designed. The question remains for Naturalists to answer: How did this occur without a Grand Designer?
Plantinga, A. (2007). The Dawkins Confusion. Christianity Today: pp. 4. Retrieved 2 Feb 2015 at http://www.philvaz.com/apologetics/DawkinsGodDelusionPlantingaReview.pdf
I strongly recommend that essay I referenced, by the way. : ) I read it for a class called Comparative Worldviews; it's a review of Richard Dawkins' The God Delusion and covers a lot more subjects than the one covered here.