QUOTE : IN THINKING ABOUT this chapter and about the limits of our perception, a familiar, oft-repeated phrase kept popping into my head: “Hindsight is 20–20.” When we hear it, we normally just nod in agreement—yes, of course—accepting that we can look back on what happened, see it with total clarity, learn from it, and draw the right conclusions. The problem is, the phrase is dead wrong. Hindsight is not 20–20. Not even close. Our view of the past, in fact, is hardly clearer than our view of the future. While we know more about a past event than a future one, our understanding of the factors that shaped it is severely limited. Not only that, because we think we see what happened clearly—hindsight being 20–20 and all—we often aren’t open to knowing more. “We should be careful to get out of an experience only the wisdom that is in it—and stop there,” as Mark Twain once said, “lest we be like the cat that sits down on a hot stove-lid. She will never sit down on a hot stove-lid again—and that is well; but also she will never sit down on a cold one anymore.” The cat’s hindsight, in other words, distorts her view. The past should be our teacher, not our master.