Armoured howitzers, kamikaze drones, HIMARS missiles. Engineers are currently showing remarkable ingenuity in designing tools of war, something I’ve had a love-hate relationship with ever since I was a student. Hate, because surely you’re better off doing something useful with everything you learnt studying mechanics, dynamics and material sciences? Build a dike. Or an irrigation system. Build a truck that can circle the globe without emitting any greenhouse gases. But designing devices that kill people as efficiently as possible and destroy buildings, vehicles or infrastructure? What would you say when you get home from work? “I came up with something really smart today: 10% more dead with every single bomb!” But the crazy thing is, when war breaks out, you’re actually glad to have those engineers on your side. At least you can shoot back if some megalomaniac madman threatens your borders. A recent episode of Radiolab, the American podcast, tells the story of two scientists using AI to develop new molecules that could help combat disease. They were shocked to discover that their specialism also has potential for something much darker. The software was set up to ensure that the new molecules cannot cause disastrous side-effects. Their view is that ‘this kind of new drug to beat a rare form of cancer may be great, but if it also causes heart failure, don’t take it’. What, the scientists wondered, would happen if you adjusted a few settings in the AI. Switched a few zeros for ones, and vice-versa. After a night of calculations, the AI suddenly came up with a very different type of molecule design. The fact that one of them was a notorious nerve gas was hardly a good omen. It also suggested a new, original variety of molecules that could be even deadlier if you tried to make them. I won’t reveal what the scientists did next. It’s an excellent podcast – I recommend you listen to it. It’s a perfect illustration of how extremely philanthropic inventions can very easily be transformed into something extremely deadly. In fact, every engineer should ask themselves the following question about every new design: what could Dr Evil do with this? Before marketing your product, maybe you could slightly adjust the design to make things a bit more difficult for the bad guys.