"Interrogating what’s going on inside our own minds doesn’t seem like it should be a difficult task. But by trying to shine a light on those thoughts, we’re disturbing the very thing we want to measure in the first place. Or as American philosopher William James put it in 1890: 'The attempt at introspective analysis… is in fact like seizing a spinning top to catch its motion, or trying to turn up the gas quickly enough to see how the darkness looks' ..." (read more)