But going further back in time that the recent past - into another age altogether, as does Orhan Pamuk in his great novel My Name Is Red, set in sixteenth-century Istanbul, or Kiran Nagarkar in his book Cuckold, set in the Rajput kingdom of Mewar around the same time - is a different matter altogether. Personal experience or the testimony of family members no longer counts for anything; a library is more useful than memory. Perhaps this is why works of fiction set in the distant past feature fictional recreations of actual historical personages - Mirabai in Nagarkar's book, Giacomo Casanova in Sandor Marai's Casanova in Bolzano. Such figures serve as a familiar anchor, as it were, in the ghostly world of distant time - they become representative of an entire age. Indeed there is a thrill in seeing them come alive, living in the moment, as they never can in history books or even biographies, which are obliged to see them through a different lens.
Daniel Kehlmann's Measuring The World, one of the unlikeliest bestsellers of this season, summons from relative obscurity two Germans of the early nineteenth century: the great naturalist and explorer Alexander von Humboldt, whose studies of the natural life of Latin America were revolutionary in their time, and the mathematical genius Carl Friedrich Gauss, still spoken of today as perhaps the greatest mathematician since antiquity. Describing the efforts of these two men to measure the world - Humboldt on arduous journeys, Gauss from the comfort of his study - at a time when "things weren't yet used to being measured", Kehlman presents a study of the single-mindedness of scientific genius, leavened by the comedy of their family life and dealings with society.
The novel's lightness of tone is crucial, because it gives it two registers, rather than the single one available from a more dedicated historical reconstruction in which the narratorial voice subsumes itself to the characters and their environment. While Kehlman faithfully summons up period details and the specifics of the work of his protagonists (he has a doctorate on the work of Immanuel Kant, so he knows the territory), he does not historicise his language - his characters are shown thinking and speaking not in archaisms but in a contemporary idiom. This is a clever compromise. The novel's language thus is always skittering on the edge of comedy, a comedy that exploits the contrast of the infinite patience of the protagonists with the challenges of measuring the world, and their absolute puzzlement with the behaviour of other, normal human beings with modest intellectual capacities and varied wants.
Gauss, for instance, feels irritation with the fact that a superior spirit such as himself should be housed in such a sickly body, while his son Eugen should be bursting with health when he is only "a common or garden-variety creature". On another occasion the boy Gauss, who can compute equations in a flash, feels incredulity at how slowly people seem to think. "Sometimes he managed to accommodate himself to them, but then it became undendurable again." On his wedding night, as his hands slide over his bride's body, Gauss sees that "a sliver of moon appeared between the curtains, pale and watery, and he was ashamed to realize that in this very moment he suddenly understood how to make approximate corrections in mismeasurements of the trajectories of planets. He wished he could jot it down…." That image of Gauss, his fingers on skin and his eye on the moon, might serve as a précis of the novel's method.
The defining feature of a historical novel is its setting in time, and the question of time is given an added edge in Kehlman's book by the way his protagonists themselves feel the yoke of time on their backs. Gauss, for instance, is acutely conscious of how speedily civilization is progressing scientifically , and thinks it unjust that "you were born into a particular time and held prisoner there whether you wanted it or not". Readers will smile at this thought, for of course reading is one of the ways in which we can escape being held prisoner by time. Even as Kehlman's readers join him in looking backwards, his protagonists are looking forwards, to a day when everything about the world will be known, thanks in part to their researches.
Another of the novel's little ironies is that both Humboldt and Gauss have no time for art, and think it a frivolous pursuit, a distraction from the main business of life. Science is about fidelity to empirical truth, but artists remarkably "held deviation to be a strength". Humboldt is shown in one scene criticising novels in which the author ties his inventions "to the names of real historical personages". That the Humboldt who does so is himself a name tied to a historical personage in a novel is one of the many witty touches in this charming book.
Here is an essay by Kehlmann on the writing of historical fiction: "Out of this World". I am not sure if his remark that "As a German writer, I can only marvel at Latin American novels; unlike their authors, I can't just invent a beautiful woman who flies away while hanging up washing, or creatures that are half-man, half-snake" is meant seriously or as a sly barb.