Neuroscience has proven that we can change our brains—and therefore our behaviors, attitudes, and beliefs—just by thinking differently (in other words, without changing anything in our environment). Through mental rehearsal (repeatedly imagining performing an action), the circuits in the brain can reorganize themselves to reflect our objectives. We can make our thoughts so real that the brain changes to look like the event has already become a physical reality. We can change it to be ahead of any actual experience in our external world.