It is sometimes said that love or perhaps money makes the world go round, but ideas have a much better claim to keeping us all spinning on our axis. Ideas are the great currency of life, driving progress and nurturing understanding – of ourselves and of the world around us – and, arguably, are the defining characteristic that elevates our species above all others. We may not be the only creature to entertain ideas – one need only glimpse a squirrel striving to liberate a feast of nuts from a bird feeder to see that – but we have the biggest and best ideas, not to mention the wherewithal to bring them to fruition. As the great architect Frank Lloyd Wright put it ‘An idea is salvation by imagination