Gerben Wierda (@gerbenwierda)

"What bugs me about this line of reasoning (which Kevin Kelly echoed just last year in his TED talk, “The future will be shaped by optimists”) is how sure it is of its conclusions." Yes, optimism shapes the world, but it may result in dystopian disasters. Many people forget that nazism offered people hope, and it had a thoroughly 'positive' streak, heaven-on-earth like. It also had a very nihilistic side, but not so much at the start. When optimists fail, they may react strongly and nihilism seems a logical reaction, the angry reaction to a (expected) paradise that is lost. Pessimists already assume things will fail, so no big reaction at failure, but when something goes well nonetheless, they are surprised and relieved. So, yes, optimists shape the future, but not in the way they expect. Both optimists and pessimists are essentially shallow, 'quick'. Realism — especially accepting uncertainties — is not our forte as humans. And it definitely doesn't sell well.