Extreme Measures by Martin Brookes

When weather forecasters point to contours on their maps, they are pointing at the scientist Francis Galton's traces, and when they speak of "anticyclones", they echo him. When people speak of nature and nurture, they echo him too, finding his "convenient jingle of words" convenient more than a century after he coined it. They have him to thank, also, for the ideological bogeyman invoked when they refer to his signature project, which he named "eugenics".

Galton's life (1822-1911) is a tasty Victorian biographical proposition, combining adventure, eccentricity and retrospectively deplorable views. Meteorology was a sideline; his grand scientific themes were genius, a quality to which he had personal claim; heredity, which he believed almost exclusively responsible for all mental faculties; and the measurement of all human characteristics. To interpret the latter he developed the concept of correlation, the statistical association of one variable with another, which taught scientists a new way to understand how things are caused. There can be no doubt of his statistical significance.

His career followed a familiar Victorian path, in which an expedition to distant parts was recorded in a name-making travel book, followed by a life of serious scholarship; the prime example is Galton's cousin, Charles Darwin. Galton himself made for southern Africa, where he led a trek into the desert interior. Martin Brookes's enthusiasm for telling his story, infectious from the start, is particularly acute in these reaches.

Here it was that Galton's passion for measurement became the vehicle for a more problematic passion. Transfixed simultaneously by what seemed the perfect specimen of that Victorian fascination, the voluptuous "Hottentot" female figure, and by shyness, he satisfied his gaze by using his sextant to measure her proportions from a distance. When offered an opportunity to touch as well as look, his reaction was explosive. Presented by his host with a young woman coated in butter, his immediate thought was for his white linen suit. Galton recalled, "I had her ejected with scant ceremony".

The attitude was Victorian, but also singular. Judging by the sceptical reactions cited by Brookes, the same was true of his ideas about "hereditary genius" and the improvement of human stock by selective breeding. (Brookes's citations raise a sore point. This book has no references, bibliography or index to support its lively narrative: Bloomsbury should be ashamed.)

This account leaves open the question of just how Galton came to believe so profoundly in heredity, though it notes the mood of pessimism which later encouraged others to turn his eugenic vision into a movement. By the time eugenics began to realise its political ambitions, universal suffrage was presenting a fundamental challenge to the eugenicists' authoritarian assumptions. Then came the Third Reich; after it, eugenics was a dirty word, and that is widely taken to be the end of the Galtonian story.

Yet today's psychologist Galtonians are confident that personality can be statistically resolved into five or six dimensions, and that heredity accounts for much variation between individuals. This, combined with a belief that intelligence can be measured and is largely heritable, is living Galtonism's grand theme. Extreme Measures is a biography that steers clear of explaining how timely it is.

Marek Kohn's 'A Reason for Everything' is published by Faber in September