This Thing Of Darkness, by Harry Thompson

Weighting the evidence

Harry Thompson's first, and Man Booker-longlisted, novel takes us through the consequences of Fitzroy's need for company, but he is writing as much about relationships as ideas. His account of the prickly friendship of the Tory prig Fitzroy and the cold-hearted Radical Darwin owes much to other novels of naval life and their forced intimacies; the spirit of Patrick O'Brian is often not far away. Thompson's Darwin is accident-prone like O'Brian's Maturin, and like him often needs naval matters explained.

Thompson has learnt from O'Brian and others how to write effective episodes of violence, danger and natural catastrophe. In the course of their zigzagging around the South Atlantic and Pacific, Fitzroy, Darwin and various companions experience earthquake, genocidal warfare and storms at sea. All are done with appropriate brio: Thompson plays fair by that portion of his readership which is reading This Thing of Darkness as part of a naval-adventure genre, in which male couples who are shadow selves are a standard trope.

Unlike O'Brian, Thompson does not entirely like either half of this couple, but dislikes Darwin more. Part of the trouble here is that Thompson is adapting the historical record for the purposes of fiction and is free to load the evidence. He can make Fitzroy's belief in biblical inerrancy a refusal to ditch religion in the face of inconclusive evidence from geology and zoology, while omitting the concurrent debates about the nature of the biblical text. The historical Fitzroy chose to ignore several sorts of evidence. Thompson also portrays Darwin as more racist in the modern sense than Fitzroy, again by shuffling his deck of facts.

In the latter part of the novel, at a point where the two have parted, Thompson editorialises in favour of Fitzroy, whose various misfortunes as inventor of meteorology and enlightened governor of New Zealand are attributed solely to a string of wicked enemies. He also uses Fitzroy to editorialise against Darwin - whose relationship with Wallace, co-discoverer of natural selection, is represented by Fitzroy as usurpation.

Thompson is using the novel to fight a battle already fought to a late draw. Our more sympathetic attitude to mental illness, and our deepened hostility to scientific racism, has for decades led to a more even-handed perception of these friends turned enemies. The days when it was standard to portray Fitzroy as a dunderheaded aristocrat are long done; indeed, the assault on Darwin by religious bigots far nastier than Fitzroy is rather more of a current issue.

This Thing of Darkness is two sorts of book: a superior adventure story and a polemic. One can enjoy the former considerably while noting that the manners of the latter are wanting. Thompson shows Darwin as sympathetic to a genocide, which the Argentinian Rosas justifies - in speeches drawn from Tony Blair. To smear Darwin with complicity in an Iraq war mounted by the anti-evolution George W Bush is quite a feat.

Roz Kaveney's 'From Alien to The Matrix' is published by IB Tauris