Top critical review
24 people found this helpful
Jury still out
on August 4, 2011
Professor Stenger sharply criticizes the fine-tuning hypothesis (FTH) of universal physical constants (cosmological constant, speed of light, Plank's constant, etc), which posits that if these constants were just a tiny bit different, life as we know it could not exist in our universe. His objections are directed to two (mostly) distinct FTH groups: religious persons citing FTH as supporting evidence for a Designer God, and to a lesser degree, scientists whose analyses support FTH, but adopt scientific rather than Designer explanations, e.g., by employing quantum mechanics and the multiverse model. My comments here mainly concern the second group.
Stenger's book contains advanced mathematics nicely supplemented with well written discussions. But, since the mathematics and associated advanced physics are essential to any serious evaluation of many if not most of the arguments, it is difficult to see how any non-physicist reader can independently judge if Stenger's conclusions are correct. Readers familiar with the writings of respected physicists Paul Davies, Roger Penrose, Lee Smolin, Leonard Susskind, John Barrow, Frank Tipler, Martin Rees, and others (all proposing arguments in favor of scientific FTH) may be quite skeptical of Stenger's unequivocal (perhaps bombastic to some) rejection of FTH in the face of these widely read works. Stenger's various analyses may or may not be valid, but I am tempted to award five stars based only on his willingness to stick his neck out. His book can then serve as a strong catalyst for more in-depth studies from the physics community. See, for example, several on-line letters and an audio interview in 2010 (site Common Sense Atheism) by astronomer Luke Barnes. For general readers, I also recommend a nice on-line lecture by Leonard Susskind concerning fine tuning in the cosmic landscape and Wikipedia (Fine-tuned universe) for a broader view of this interesting topic.
*** New posts Dec 20, 2011 to Feb 18, 2011: As expected, the physics community has responded to Professor Stenger's analyses with critical review. See new counter arguments by Astronomer Luke Barnes and Stenger's reply to Barnes on-line. Stenger emphasizes that his book was intended to refute claims that our universe is fine tuned "for us." But, his book seems to make much stronger claims (implicitly omitting the "for us" caveat) that put him at odds with many cosmologists. In response to several comments, I add the following clarification to my original review:
It is useful to separate the FTH into two parts, call them the "easy" and "hard" problems. An analogy for the easy problem is thus: Suppose physics predicts that a certain set of parameters results in a universe consisting of nothing but neutrinos (Universe A) and a second set of parameters yields nothing but photons (Universe B) and so on for other possible universes. We then examine the parameter space (the cosmic landscape) and find that our estimate of the probability of A is more than 10 to the 100 times lower than the probabilities of B, C, etc. In this sense Universe A is "special," and this fact could have implications for further studies in cosmology. (It might be even more interesting if the landscape proved to be fractal.)
Similarly, if the parameter set leading to universes that are life-friendly is very small (compared to other possible outcomes), Susskind, Barnes, Davies, Penrose, etc. argue that this can have profound implications for cosmology; perhaps the most obvious is adding credence to the multiverse model.
If one accepts the FTH in this sense, then the next ("hard") question is how to interpret this result. Davies has listed about a dozen possible explanations. Some involve pure chance and/or the multiverse and others are consistent with god hypotheses. Not surprisingly, the latter are favored by religious advocates, but whether science can ever sort out all these options is an open question. Stenger departs from mainstream cosmology (as far as I can tell from the literature) by claiming that there is no FT to begin with so there is no "hard" question to answer. My criticism of his book has nothing directly to do with the hard problem itself, which my card deck analogy (below) addresses. I awarded three stars based on Stenger's raising provocative and interesting issues even if many of his conclusions turn out to be wrong. Those interested in this fascinating topic should check the other 2 and 3 star reviews and their criticisms.
***End of new posts
Rather than address technical issues, I propose here a simple metaphor to suggest that the hard problem is not easily settled even by employing our best science and statistics. Suppose a friend shuffles an ordinary card deck and deals all 52 cards to you face up, resulting in a remarkable sequence in which cards are perfectly bunched, AAAA, KKKK,...,2222. I have labeled this sequence "remarkable," but the probability of this or any other sequence of 52 cards occurring in the absence of non-random external influences is about 10 to the minus 68. Thus, one might argue that SOME sequence had to occur, and this one is just as likely as any other. But I, for one, claim that the (subjective) probability that this sequence was created by a human designer is very close to one; most likely your friend just introduced a "cold deck" while you were distracted.
Now suppose the deck is again shuffled and dealt, resulting is some more subtle pattern, say only the 2's, 3's, and 4's are bunched. At what level of bunching are we so surprised that we suspect "foul play" by some external influence, be it designer or physical mechanism? Our answer may depend critically on whether a substantial bet was involved; gambling has a rich history of ingenious cheating.
Suppose we choose some code such that each card designates a letter. Your friend deals again, and low and behold, a sub-sequence yields "jesuslovesyou" in the midst of an apparent random sequence. We can estimate the probability that a string of 13 letters will yield English words, but what about all the other Earth languages, or even alien languages. Furthermore, we can think of many kinds of patterns that seem very special to most of us that have nothing to do with any known language as in my first example of bunched number sequences.
Generally, there exist 10 to the 68th distinct card sequences, but how do we separate the subset of "special" sequences from "ordinary" sequences? Can some hot shot statistician answer this question? I don't think so because the "specialness" of any particular card sequence appears to be partly a matter of individual taste; it is observer driven. Perhaps special patterns are like pornography, we can't define them but each of us "knows" one when we see it (even though we don't agree on the more subtle cases). Just how special is intelligent life? While this card metaphor greatly oversimplifies the FTH issue, it perhaps suggests that the answer may not yield so easily to scientific or statistical study.
Readers interested in issues like brain complexity and human consciousness may check my new book (2010), which also touches on cosmology and the fine tuning issue.