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Life's a Double Helix

Book Review: In Search of the Double Helix - Quantum Physics and Life, by John Gribbin
As a teenager, I bought John Gribbin's In Search of Schrödinger's Cat and In Search of the Big Bang. However, I dropped biology at the first opportunity (along with history and modern languages), and I stumbled on this volume a couple of years ago at a secondhand bookshop at Camden Market.

Unlike the population at large, the thing I didn't like about biology was its relative lack of rigour; it was very vague, illustrative and qualitative, where physics was specific and quantitative. To be fair, Gribbin's book focuses on biochemistry rather than biology, and some sections of it are written very much from a physicist's viewpoint.

The first few chapters give some background: Lyell, the geologist; Darwin, the botanist; and Mendel, the Meddlingstatistical monk. In the middle section of the book, Gribbin jumps straight in to a slimline description of quantum physics. It's accurate, but minimal: I suppose most people like their physics that way, if at all. Nevertheless, if you don't appreciate the consequences of quantum physics, the progression to quantum chemistry will be meaningless. At A-level, chemistry became less rigorous for me, with things like hydrogen bonds, where an axis defined one end of a bond or molecule as "slightly positive" and the other as "slightly negative". With Gribbin's explanation that it is all down to the probability distribution from the molecule's wavefunction, this becomes conceptually obvious - if you understand the base concepts, that is, and there probably wasn't enough material earlier in the book for you to take that on anything other than blind faith.

The book then proceeds to describe some techniques, such as X-ray crystallography, chromatography and electrophoresis, that were used in the rather ungentlemanly search for the bearer of the genetic code and its structure. To some extent it sounds as though Crick and Watson triumphed despite themselves, neglecting or ignoring some inconvenient data which did not fit their initial theories. Nevertheless, Gribbin's explanation of the elegant base pairing rules in the DNA strands, and how that naturally lends itself to reproduction, elevates the discussion.

The final chapters follow the subsequent analysis of DNA and its role in determining evolutionary links and rates through random mutation. Darwinism just seems obvious to me, though I wasn't brought up in a particularly religious context. Gribbin makes some references to creationism in the early chapters of the book, noting it in a historical context but pervasive through to the 1980s, when the book was written. There is no mention of the more recent "intelligent design" notion. It's difficult to argue against creationism or intelligent design, not because they are strong theories, but because anyone who believes them is likely to perceive them as "rational" just as much as a scientist perceives evolution as "rational". The difference in science, perhaps, is that there is no convenient Book of Absolute Truth, but only experiment, doubt and scepticism, which are to be encouraged in order to improve our understanding of the world.
Tags: books, science
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