Ultimately, what defines the ‘cult of optimism’ and the culture of positive thinking – even in its most mystically tinged, New Age forms – is that it abhors a mystery. It seeks to make things certain, to make happiness permanent and final. And yet this kind of happiness – even if you do manage to achieve it – is shallow and unsatisfying. The greatest benefit of negative capability—the true power of negative thinking—is that it lets the mystery back in.