The supreme visualiser describes Leonardo da Vinci as…a consultant:
Leonardo was bewilderingly versatile. So much so that it is hard to say exactly what he did for a living. He was of course, an artist. But he completed remarkably few paintings and even fewer sculptures. Like Marcel Duchamp in the 20th century, he was highly influential, but abnormally unproductive. Those pictures he did more or less finish — the Mona Lisa, for example — he tended to keep rather than deliver to the clients who had originally commissioned them. Yet he was paid for doing something — the question is what.Part of the answer is that he was, as the art historian Martin Kemp puts it, using a rather nebulous contemporary term, “a consultant”. As a “master of water” Leonardo proffered expert opinions on such questions as the canalisation of rivers, and the use of pumps. In another practical capacity, he was a roving military adviser for Cesare Borgia – the aggressive Renaissance warlord who was the model for Machiavelli’s Prince. Additionally, Leonardo was adept at designing costumes and sets for theatrical spectacles — masterpieces of Renaissance performance art just as worth looking at, for their lucky audiences, as any altarpiece or portrait. In modern terms he combined the functions of David Hockney, a staff officer in the Royal Engineers, an official of the local water company — plus a touch of Professor Stephen Hawking.
Leonardo finally made a job just out of being himself. The French king Francis I, according to Benvenuto Cellini, was so taken with him “that there were few days in the year when he was parted from him”. The monarch “could not believe there was another man born in this world who knew as much as Leonardo”.
Francis was probably correct. There is a sense in which Leonardo tried to know too much – he was, after all, a rough contemporary of Doctor Faustus. That was both the source of his failure, and precisely what makes him so fascinating. He was constitutionally incapable of considering one problem without a host of other intriguing lines of inquiry at once occurring to him.