When J K Rowling was invited to deliver the commencement address at Harvard University, she chose to speak to the graduating class about two topics very close to her heart: the benefits of failure and the importance of imagination. Having the courage to fail, she said, is as vital to a good life as any conventional measure of success; imagining ourselves into the place of another - particularly someone less fortunate than ourselves - is a uniquely human quality to be nurtured at all costs.