Richard Peachey comments on Paul Davies:   40 billion habitable planets in our galaxy?  

Interesting article by physicist (and frequent “origin-of-life” commentator) Paul Davies in today’s National Post (reprinted from The New York Times of Nov. 18):

 
 
While keeping faith with Darwin, Davies nonetheless makes the following noteworthy statements (colouring is mine):
 
• “In spite of intensive research, scientists are still very much in the dark about the mechanism that transformed a nonliving chemical soup into a living cell. But without knowing the process that produced life, the odds of its happening can’t be estimated.”
 

• “When I was a student in the 1960s, the prevailing view among scientists was that life on Earth was a freak phenomenon, the result of a sequence of chemical accidents so rare that they would be unlikely to have happened twice in the observable universe. . . . Today the pendulum has swung dramatically, and many distinguished scientists claim that life will almost inevitably arise in Earthlike conditions. Yet this decisive shift in view is based on little more than a hunch, rather than an improved understanding of life’s origin.

 

• “The underlying problem is complexity. Even the simplest bacterium is, at the molecular level, staggeringly complex. Although we have no idea of the minimal complexity of a living organism, it is likely to be very high. It could be that some sort of complexifying principle operates in nature, serving to drive a chaotic mix of chemicals on a fast track to a primitive microbe. If so, no hint of such a principle has been found in laboratory experiments to re-create the basic building blocks of life.

• “If life does pop up readily in Earthlike conditions, then it should have started many times, right here on our own planet. It could be that intermingled among the seething microbes all around us are some that are so biochemically different they could be descended only from a separate origin. You couldn’t tell by looking, only by delving into their molecular innards and finding something weird enough to rule out a common precursor. The discovery of just a single “alien” microbe under our very noses would be enough to conclude that the universe was indeed teeming with life.” [Note: The word “would” in the previous sentence tells us that no such discovery of any “alien” microbe has been made!]

I liked the following reader comment:

 

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James Currin

Stamford, Ct.

I don’t know whether or not we are alone in the universe. What I do know is that, thanks to Paul Davies’ article, I am not alone in my belief that all the statistical arguments for the inevitability of a universe teeming with life are fatuous. As he so elegantly puts it, “No statistical evidence can be drawn from a sample of one.” 

I believe that the father of the argument from large numbers, is the once quite famous Carl Sagan. His technique of overpowering audiences with phrases like “billions and billions and billions” was often parodied, but seemed to capture the popular imagination. When I was a young professor, it fell my lot to teach, with a colleague, a course with the unassuming title, “Cosmic Evolution”. The principle text for the course was a book by Sagan and some Russian whose name I forget. At some point in the text Sagan presented his “proof”, not only that extraterrestrial life exists, but in huge quantity. The proof consisted of a very plausible string of probabilities with the strange omission of the only important one—the probability that life would arise in the presence of the most favorable conditions, whatever they are. I remarked on this to my colleague, but I can’t recall his reply.

The recent claims by giddy scientists that conditions on Mars may have once been favorable for the creation—sorry, strike that—the emergence of life are silly. They can’t possibly know what conditions are favorable for an event they have never observed.

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