I was reading an article about Oprah’s book, The Path Made Clear, in which she argues that having purpose is the key to happiness. Nothing to argue with there, I thought, from the Queen of Self-Help. My eye moved to the sidebar – Oprah’s celebrity pals were giving their purpose in life with a lot of wordy self-help speak: “honouring your own life” (Elizabeth Gilbert), and a particularly rambling, “if you’re full of love, if...