“When there are lots of possibilities, most of the work goes into just locating the true answer - starting to pay attention to it. You don't need proof, or the sort of official evidence that scientists or courts demand, but you need some sort of hint, and that hint has to discriminate that particular possibility from the millions of others. Otherwise you can't just pluck the right answer out of thin air. You can't even pluck a possibility worth thinking about out of thin air.”