Kaines: The idea that a stock price to day could embodya expectation of what might happen to morrow is profound and true. Woun, it starts with an idea that it's quite deep. And that is at the root of how economists do think about uncertainty, which is that expectations matter. Kaines: If i plant a fruit tree, people assume it has no value until it produces fruit. That is not true. It has potential value because people anticipate, correctly, that fruit will come but it's not worth zero.