In times of strife, governments are less reluctant to give scientists the money they need.
Dubai da Vinci show points to conflict's upside for innovation
Visitors to the Leonardo da Vinci Exhibition in the Burjuman Mall in Dubai have reportedly been voicing their disbelief that one man could do so much.
Best known for his art, da Vinci's claim to the title of the first and greatest of Renaissance men is certainly done no harm by the dozens of exhibits that show his passion for technology - much of it 500 years ahead of his time.
From robot men to drum machines and flying drones, his inventiveness is inspirational. The stimulus for much of it is, however, altogether darker.
After finishing his 10-year apprenticeship with a Florentine artist, 25-year-old da Vinci became a freelance artist and needed a source of revenue.
During the 1470s, Florence was at war with the Pope's forces in Rome, and military craftsmen were exploiting this golden business opportunity. Da Vinci decided to take the chance to make money out of his ingenuity, and began work on a host of ideas: multi-barrelled guns that presaged the Gatling gun 400 years later, recoilless rifles, better gun-carriages, more effective siege equipment.
The war ended in a truce before da Vinci could make anything from his designs, but he returned to the same source of inspiration years later to win the patronage of Ludovico Sforza, the Duke of Milan.
As a demonstration of his inventiveness, he put together a portfolio of what he would do for the Duke. The bulk was focused on military technology and contained an astonishing range of prescient ideas, among them a self-propelled armoured vehicle with guns pointing out - in other words, a tank.
Da Vinci had recognised that while patronage of the arts ebbs and flows, there is always money for the art of war. In this he was following in the footsteps of another genius: Archimedes, mathematician, physicist - and chief weapons designer to King Heiro II of Syracuse.
It would be easy to cast aspersions on such motivation, were it not for the awkward fact that the exigencies of war have spawned inventions that have improved far more lives than they have destroyed. For as da Vinci and Archimedes discovered, wars have a habit of persuading nations to cut through supposedly "insuperable" barriers of cost and manpower.
Take the case of that most fertile of inventions, the computer. The idea of building a universal problem-solver is far older than one might think: historians generally credit the first attempts to build such a device to the English mathematician Charles Babbage, who floated the idea in 1834.
Despite the revolutionary nature of his so-called Analytical Engine, the British government refused to give Babbage the resources he needed to build it. This was largely because he had failed to complete a far simpler mechanical calculator, the Difference Engine, despite generous state support.
But it is significant that Babbage put forward his ideas during the so-called Pax Britannica, the 100 years following the Battle of Waterloo in 1815, during which there was no serious threat to Britain's survival. Small wonder, then, that the British government was reluctant to pour vast sums into such a speculative project.
Now fast-forward to 1941, with Britain facing annihilation by the forces of Nazi Germany. A team of codebreakers was having some success in cracking enemy ciphers, but was in desperate need of more technology and manpower to speed the process.
They wrote to the prime minister, Winston Churchill, pleading for help, and on a memo headed "Action this day" he instructed his underlings: "Make sure they have all they want on extreme priority and report to me that this had been done."
Within two years, the codebreakers had built Colossus, the forerunner of the computer, which they used to break the ciphers used by Hitler and his commanders.
The turbocharging effects of war can also be seen in medicine. Everyone knows how the Scottish bacteriologist Alexander Fleming discovered penicillin one day in 1928, after noticing dead bacteria on a dish containing some mould.
Yet this familiar story omits the fact that Fleming was unconvinced that the mould Penicillium notatum was of much benefit for humans, and failed to turn it into the miracle cure it later became.
Credit for that goes to the Australian pathologist Howard Florey and the German-born biochemist Ernst Chain. Following the outbreak of the Second World War, they worked relentlessly to purify the bug-killing penicillin exuded by the mould. They were in a race to save the lives of the countless wounded soldiers who died from relatively minor injuries because of bacterial infection.
The first human trial took place in Oxford, England, in 1941. The patient died, because the doctors could not get their hands on enough penicillin.
In desperation, Florey went to America to persuade the giant pharmaceutical companies to start mass-producing it. By the time of the Normandy landings in 1944 there was enough of the "wonder drug" to treat all the severe cases of bacterial infection that broke out among the troops - and countless lives were saved. A year later, Florey and Chain shared the Nobel Prize for Medicine with Fleming for one of the greatest advances in medical science.
The mere threat of war between the superpowers of the US and Russia propelled the development of nuclear power, aerospace technology and global communications. Anyone who has been guided home using GPS should give thanks to the US Pentagon, which set up the satellite network to guide weaponry.
The Harvard professor Steven Pinker has provoked a storm of controversy with his new book, The Better Angels of our Nature, which argues that we humans are becoming less violent towards one another. That we also live in a technological golden age is cheering evidence that the age-old link between inventiveness and war is finally being broken.
l The Da Vinci Exhibition is free and open until 10pm tomorrow.
O Robert Matthews is visiting reader in science at Aston University, Birmingham, England.