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Monday, May 17, 2021

Causal Adequacy

Frank Wilczek is a very bright man, a Nobel Prize-winning physicist, but sometimes very bright people say things that leave one scratching one's head.

In a recent Wall Street Journal column he draws a comparison between the precision found in living cells and the precision required in technology. The former is certainly impressive, as anyone who has read about how living cells work can attest.

He starts off his column with this:
Precision is a powerful tool, but it can be hard to come by. That theme, with variations, is a leitmotif of science, organic life and modern technology. It is sounding again today, at the frontier of quantum computing.

Consider biology. Complex organisms store their essential operating systems—instructions for how to build cells and keep them going—within long DNA molecules. Those basic programs must be read out and translated into chemical events.

Errors in translation can be catastrophic, resulting in defective, dysfunctional proteins or even in cancers.
There's nothing problematic about any of that, but then he concludes this observation with an off-handed comment that's tantamount to waving a magic wand while saying abracadabra:
So biology has evolved an elaborate machinery of repair and proofreading to keep error rates low—around one per billion operations. A series of complicated molecular machines examine the progress and correct mistakes, in a process aptly called proof-reading.

The creation of this machinery is one of evolution’s greatest achievements.
It's uncertain, of course, what he means by "evolution," a protean term that has several shades of meaning, but it appears from the phrase "biology has evolved" that he intends Darwinian evolution - the development of the enormous diversity of living things from a single ancestral cell via purely natural processes like chemistry and chance.

If so, then the sentences I've highlighted in bold-face are an expression of a marvelous degree of blind faith in the power of those processes.

I say blind faith because blind faith is a belief in something despite the lack of any evidence for it. There's simply no evidence that chemistry and chance can generate the information necessary to produce the very complex machinery and systems that Wilczek describes and there are good reasons to believe that they can't.

Such systems require dozens of proteins, all working in a coordinated fashion to achieve a certain end. Yet the odds of just a single functional protein of modest length being produced by the random connections of amino acids in some hypothetical prebiotic environment are something like 1 chance in 10^164. This is so astronomically improbable that it would be a miracle if it happened just once let alone dozens of times.

And that's just what's necessary to produce the proof-reading machinery. An actual cell consists of hundreds of proteins, all choreographed to perform myriad functions. Not only the production of the proteins but also their choreography all require information, and no one knows how random, accidental processes could generate that information, especially in the first cell.

Indeed, what we do know about natural processes is that they are exceedingly more likely to degrade information.

Another Nobel-Prize winner, Francis Crick, reflecting on the enormous difficulty in trying to imagine how chemistry and chance could create the equivalent of a library of information before any life existed said,
An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle, so many are the conditions that would have to be satisfied to get it going.
Crick used the word "almost" because he didn't believe in miracles, but he didn't know what else to call the organization of the first life.

Paul Davies in his book The Fifth Miracle is at pains to avoid using the term "miracle" to describe the origin of biological information, but by the end of the book, after all his attempts to find a plausible, non-miraculous solution to the problem of life's genesis, he's no closer to an answer than he was when he started.

Here's the problem for folks like Wilczek, Crick and Davies: Nature just doesn't create information, but intelligent agents do it all the time. Chemistry and chance by themselves lack causal adequacy as explanations for the origin of the biological information packed into proteins and DNA, but scientists can relatively easily synthesize functional proteins and nucleic acids in the lab.

It seems, then, that the most plausible explanation for the origin of the amazing biological error-correcting systems Wilczek discusses, are, like technological error-correcting systems, the product of intelligent engineering. It's the explanation that relies upon what we know about information and its causes.

As Stephen Meyer writes in his excellent new book The Return of the God Hypothesis, causes known to produce a given effect are judged better explanations than those causes which are not known to produce that effect.

Intelligent minds are the only causes known to be able to generate large amounts of specified information, so why Wilczek so insouciently assumes that the massive amounts of information required by a functioning cell are the product of blind, mindless, accidental processes is certainly puzzling, to say the least.