Sewing The Seeds Of Biology’s Post-‘Shannon Information’ Era
|August 13, 2009||Posted by Robert Deyes under Intelligent Design|
Synopsis Of The Fourth Chapter Of Signature In The Cell by Stephen Meyer
ISBN: 9780061894206; ISBN10: 0061894206; Imprint: HarperOne
When talking about ‘information’ and its relevance to biological design, Intelligent Design theorists have a particular definition in mind. Indeed they see information as “the attribute inherent in and communicated by alternative sequences or arrangements of something that produce specific effects” (p.86). When the twentieth century American mathematician Claude Shannon laid down his own theory for quantifying information he drew attention to a mathematical relationship that on its surface appeared intuitive. Information as Shannon noted was inversely proportional to uncertainty. That is, the more information we had about our world the less uncertainty there was over the outcome of future events. Shannon also proposed that the more improbable an event the more information such an event would impart once it actually took place (say, throwing a six on a role of dice).
Nevertheless Shannon’s theory was deficient in at least one crucial aspect- it made no distinction between meaningful and meaningless information-rich strings. While equally long sequences of alphabetical characters did not always elicit tangible (meaningful) outcomes, they nevertheless always displayed the same level of Shannon-style uncertainty. And yet language in itself was more than a random assortment of letters even though Shannon’s theory ascribed the same degree of information content to such an assortment as it did to an equally long but meaningful series of sentences.
What was missing in Shannon’s synthesis was a term that accounted for the so-called ‘specificity’, that is the “precise arrangement or sequence” of letters in, say, human language (p. 100). Therein lay a biological connection. After all, the swinging 50s brought with it a host of scientific breakthroughs, notably those of X-ray crystallographers Fred Sanger and John Kendrew who were instrumental in unveiling the ‘twisted, turning, tangled chain’ nature of proteins. In so doing they sewed the seeds for a process of discovery that would eventually culminate in an unexpected realization- proteins contained a high degree of structural and sequence specificity. That is, if proteins were to fulfill their hugely diverse repertoire of functions in the cell both their structural organization and amino acid sequence had to fit within a very narrow subset of all possible arrangements. Just like human language that only takes on meaning when letters and words are set out in universally recognizable and interpretable sequences, proteins could be considered as being rich in specified information.
In 1958 Francis Crick’s Sequence Hypothesis formalized the idea that protein amino acid sequences were inextricably linked to the base sequences of DNA. Years earlier, geneticists George Beadle and Edward Tatum had supplied evidence that strongly suggested a link between genes and proteins. The elucidation of the DNA genetic code in the 1960s, defining the base triplets that coded for each amino acid, revolutionized the molecular biology arena. Most significant of all was the revelation that both DNA and proteins bore the same ‘specificity’ fingerprint as human systems of code. In short, the cellular world appeared to be intelligently designed.
In the fourth chapter of Signature In The Cell, Stephen Meyer displays an enviable clarity in his exposition of biology’s post-‘Shannon information’ era. In so doing he masterfully dispels any concern that the intelligent design inference does not carry with it a sound scientific foundation.