Hector Avalos, a professor of religious studies at Iowa State, has a "review" of the book The Privileged Planet, by Iowa State astronomy professor Guillermo Gonzalez and Jay Richards, a philosopher, up at Talk Reason. Talk Reason is a site that argues against creationism, intelligent design, and religious apologetics, and The Privileged Planet is a book presenting an astronomical argument that the universe may be designed.
I put the word "review" in quotes deliberately, because it's more of an attack on intelligent design generally than a review of the book; in fact, it says very little about the book itself. It begins by summarizing the book this way:
TPP discusses an array of data to buttress its argument that Earth was intentionally positioned where it is. For example, if our planet were much farther from, or much closer to, the Sun, then life might not exist. Also, "the mere presence of other planets in the inner Solar System reduces the number of asteroids and comets hitting Earth" (p. 115), and so helped ensure that such perils to life would be minimized. Earth is much better than Mercury for "measurability" of the universe because the latter planet "completes three rotations every two orbits" and so "would offer more confusing vistas" (p. 106).
From these and other data, TPP infers that our planet must have been intelligently placed in just this location in order for intelligent life to emerge that could then produce astronomers to observe the universe and discover the Designer's intentions.
This is hardly an accurate summary of the book's arguments. Indeed, the book does mention the presence of other planets, and the number of rotations, but these are relatively minor points. The overarching theme is pointing out the confluence of two interesting facts: First, as has been noted before, planets like the Earth, which have the potential of being habitable, are fairly rare. That is, the number of factors necessary for a planet to be like the Earth (even generally speaking) are quite high, meaning that Earth-like planets must be rare in the universe. One can quibble about how rare, but that's not the issue here. Additionally, from many planets, observation of the universe would be much more difficult. The Earth happens to be at a place in our galaxy where it is remarkably easy to see out of our galaxy into other galaxies. Furthermore, it also happens to be ideally situated for certain other observations, like those of total solar eclipses. The book points out that we're on the only planet (or moon) in our solar system where the moon just perfectly blocks out the sun, allowing the very outer layer of the sun's atmosphere to show around the sun. This makes possible some scientific discovery that wouldn't be possible (or would be much more difficult) without this fact.
So, overall, the book argues that not only are conditions for habitability ideal here on Earth, but also, conditions for scientific discovery are way better than most other places we could possibly be. This is an interesting coincidence, if true, because there is no apparent reason why the conditions for habitability should coincide with the conditions for scientific discovery. That is, if habitable planets were randomly distributed throughout the universe, one would expect that, since most locations wouldn't have the same favorable conditions for scientific discovery that we have here, most habitable planets wouldn't have these favorable conditions.
Unfortunately, Avalos seems to ignore this two-fold argument, and focuses only briefly on the first part (fine-tuning of conditions for habitability). He does briefly mention the bit about eclipses:
Even more puzzling is that Dr. Guillermo Gonzalez, who is an astronomer, concludes that the earth was positioned for his convenience (in order to make scientific measurements of the universe). He begins Chapter 1 of TPP with a story about how the observation of a solar eclipse led him eventually to posit the idea that Earth was positioned so that he could make such observations.
This is hardly the point of the eclipse story. Rather, it, and many other examples from the book, highlight the fact that our position in the universe is far better for scientific discovery than most positions. Either one must believe that we, by chance or natural law, happen to be in a place where conditions for scientific discovery are far above average, or that the universe was designed so that we would be in such a place. Avalos does neither; rather, he simply suggests that Gonzalez is some sort of a quack: "This rationale is analogous to a plumber arguing that if our planet had not been positioned precisely where it is, then he might not be able to do his work as a plumber."
Avalos also argues that fine-tuning arguments, which point out the number of factors which must be "just right" in order for life to be possible on Earth and thus suggest habitable planets (and life) are rare, are absurd. I have to admit, here I can't really understand his argument. It seems to hinge on this statement: "The main assumption is that the amount of physical constants and entities that "must be right" to produce any entity X is generally proportional to the amount of the Designer's purpose for X." I don't know what he means "the amount of the designer's purpose." I mean, if I apply this to whether the Earth was designed, I would conclude that since there are a lot of factors which must be just right for the universe to have planets at all, and even more for the universe to have potentially habitable planets, etc., "the amount of the designer's purpose for Earth" must be fairly high. I have no idea what that means. I mean, either Earth was designed or it wasn't.
I am fairly familiar with these fine-tuning arguments, and they seem to me to be fairly reasonable. That is, if we can definitively conclude that factors X, Y, and Z are necessary for a habitable planet to exist, and we know that the probability of having factor X anywhere in the universe is P(X), the probability of Y is P(Y), and so on, then the total probability of having these factors is P(X)*P(Y)*P(Z). If these are each 1/10, for example, then the probability of having all three at once is 1/1000. Then we can multiply that number by something relating to the total number of "chances" at getting this right (perhaps the total number of planets or something) to see how likely we are to have a habitable planet. With those numbers, it would be likely to have habitable planets. But what happens with fine-tuning is that a great number of factors appear to be necessary for habitability, and each seems to be quite rare, so the total probability begins to appear astronomically small.
Even astronomers who don't believe in Intelligent Design or creationism will agree that these fine-tuning arguments make some good points. There are, however, legitimate objections to fine-tuning arguments (like arguing that we don't know the relevant probabilities and factors, or that there might be underlying principles which set these that we don't know about, or that perhaps there are multiple universes and so we are, of course, making observations from the one (or one of several) universe where all of the factors converged just right for us to exist). Maybe Avalos didn't want to concede that fine-tuning arguments make some legitimate points so he didn't bother discussing these potential arguments against fine tuning. Instead, he says this:
The utter superficiality of the argument in TPP becomes apparent when one realizes that our planet has millions of features that we could identify as unique. These million other features also might not exist if our planet were any closer to, or farther from, the Sun; or had any other of the positional features in the solar system or galaxy that TPP touts as conducive to intelligent life.
For example, if our planet were not located precisely where it is, then we might also not have AIDS viruses, congenital deformities, or death itself. So why do ID proponents think that life and intelligence were the features selected for intelligent design? Why don't ID proponents argue that our planet has been positioned where it is so that AIDS viruses, congenital deformities, and death could exist?
Fine-tuning arguments work by trying to identify factors which are essential for habitability -- not simply unique features. The debate needs to be about which factors are essential for habitability. For example, if I tell you that I know a certain insect that can only live in deserts where the average rainfall is less than 10 inches per year and the winter/nighttime temperature never gets below 45 degreees Fahrenheit, and ask how many such deserts are on Earth, you can't respond by saying that I'm pointing out only a small number of possible unique features describing a desert, which might not exist if I specified a different kind of desert. Rather, you've got to get out your geographical information and start looking to see how many deserts meet those conditions. Or maybe you'll object and say your data suggests that they can survive even if the average rainfall is up to 12 inches a year. The point is, we're talking about conditions necessary for habitability, and THEN trying to figure out how many habitable planets there are likely to be. Avalos seems to have ignored this point.
The rest of his essay is devoted to pointing out similarites between some of these fine-tuning arguments and other fine-tuning arguments presented by various scientists and theologians in the past, mostly to argue that (a) the Privileged Planet doesn't present "a new argument or even using much new basic data". Well, of course. The data in the book has been published previously in peer-reviewed journals, and there is a long history of fine-tuning arguments. The new thing about the Privileged Planet isn't either of these. It's the interesting observation that the conditions for habitability just happen to coincide with those for scientific observation. I think this is a very interesting observation whether or not you think this confluence is due to design, but it's an observation that Avalos apparently doesn't understand.
In closing, it's probably also worth mentioning that Avalos circulated a petition fairly recently among the faculty at Iowa State (which you can read here) which has been seen by some as a thinly veiled jab at Gonzalez. It included this closing language:
We, therefore, urge all faculty members to uphold the integrity of our university of science and technology, and convey to students and the general public the importance of methodological naturalism in science and reject efforts to portray Intelligent Design as science.
I'm rather disappointed by Avalos's review; one would hope he would have at least tried to really understand the arguments made in the book before objecting to it. I do find it also somewhat ironic that he's a professor of religious studies, yet he's the one arguing that what Gonzalez is doing isn't science.