If I could teach the world just one thing about science, it would be that the ideas you have in mind, and that seem so certain to you, might be wrong. Science is based upon questioning received ideas, discussing them, and always searching for novel and more effective ways of thinking the world.

Science is not about certainty; it is about doubt. It is certainty that makes us blind and stupid. The worst moments in the history of civilisation are the ones when somebody has power, and is totally certain that they have the Truth, the only and final Truth.

Carlo Rovelli is author of Quantum Gravity (buy this book from Amazon (UK) or Amazon (USA)). See his website.