First I'd like to apologize for being late with this post. I was a little busy last week and didn't get around to writing a God Delusion post. Anyway, as promised I'm now going to talk about the anthropic principle and how it works as an argument.
As I mentioned last time, the next two sections of chapter four both deal with the anthropic principle. The first section talks about how the anthropic principle applies to the planet earth.
We now know that not all planets are able to support life. In fact there are a number of factors that make our planet and our solar system especially suited for the evolution of complex life. At first this might seem like an odd coincidence, except that if our planet didn't have just the right conditions then we wouldn't be here to talk about it. We'd be on some other planet that is well suited for the evolution of complex life having the same discussion.
Dawkins uses the argument to address the problem of how life appeared on earth in the first place. He argues that even if we discover that it is extremely unlikely that life could have emerged from nonliving matter, say one in a billion, then life still would have appeared because there are almost probably more than a billion habitable planets in the universe.
Here the argument works very well, because we know that there are billions of galaxies containing billions of stars. Of course, we still don't know all of the probabilities. We don't know how likely it is that a given star has an earth-like planet with all the right conditions to support life. We don't know how likely it is that life emerged from nonliving organic compounds. So we can't be certain that life emerging from nonliving organic matter on an earth-like planet is a sure thing, but it does seem reasonable*.
In the next section Dawkins talks about how the anthropic principle applies to the universe as a whole. He mentions the fact that, from the standpoint of contemporary physics, several of the fundamental constants of the universe seem to be "just right" for life, much like our planet and our solar system.
Obviously the same trick won't work here. After all, we can see that the universe is large and it contains a vast quantity of stars, any one of which could contain a life-friendly planetary system. Our universe, on the other hand, is the only one we've got. If this universe wasn't fit for life, then we wouldn't exist. There isn't any other universe for us to evolve in.
Unless we hypothesize, as Mr. Dawkins does, that there are many different universes each with different fundamental constants. Then we could use the same argument to show that the fact that our universe is fit for life is unremarkable.
The fact that Mr. Dawkins is credulous enough to think that a multiverse theory is plausible, after all the incredulity he's shown towards religious beliefs, is shocking. What evidence could anyone provide, either experimentally or observationally, to prove that these alternate universes exist? They aren't a part of our universe at all and they may not be connected with our universe in any way. They are as undetectable as Russell's Celestial Teapot, the Invisible Pink Unicorn or the Flying Spaghetti Monster.
Back in Chapter Two, in the section on Monotheism, Dawkins wrote this to describe the Abrahamic God, "He not only created the universe; he is a personal God, dwelling within it, or perhaps outside it (whatever that may mean)." Notice the incredulity Dawkins shows at the idea that anything could exist "outside" the universe. But where do these alternate universes exist? Certainly they must be "outside" our universe(whatever that may mean). Interestingly the same idea, which seemed absurd coming from a theologian, suddenly seems completely reasonable coming from a theoretical physicist.
So we see that Dawkins is not really a true skeptic. He is a selective skeptic. He is highly skeptical of religious ideas and beliefs, but much less skeptical of scientific-sounding ideas. Even when those ideas have the same amount of evidence, in fact even when it's the exact same idea, the sciencey sounding one is deemed "plausible" while its religious equivalent is considered preposterous.
I have some more thoughts I would like to share on this topic, but I'll save them for next week. I've also discovered, after reviewing chapter four, that I still have one more section to cover. So I hope you're enjoying my coverage of chapter four, because it's going to continue for a couple more weeks.
* Advocates of intelligent design theory disagree. They argue that the appearance of life from non-living matter is so improbable that it is basically impossible. I personally disagree, but I'm not an expert on the subject. If you want to learn more I found a website that provides a rebuttal to the intelligent design argument.