From Agatha Christie doing the dishes to the cancer surgeon inspired at the theatre, an idling brain suddenly seems able to join the dotsIf you really want to solve a problem, try doing nothing about it. Fold some laundry. Stir a risotto. Go for a run, watch a film, try to entertain someone else’s baby: anything that involves pottering about in an undemanding yet still vaguely engaged way, which absolutely couldn’t be classed as work but isn’t totally vegetative either. It may not be the productivity hack any go-getter wants to hear, but it’s surprising how often a spell of aimless noodling around frees an otherwise overworked human brain to make the kind of lateral mental leap that helps everything fall into place. And I’m not just saying that to justify a New Year’s Day spent lying hungover on the sofa, ploughing through the last of the Christmas cheese.For the eminent cancer surgeon Michael Baum, it was a night off with his wife at the theatre that allowed him to suddenly join th...