Think of all the hundreds of people from whom you learned about the world, and the hundreds of people from whom they learned about the world. Then throw in all the people who want to sell you something, and all the people who think it's perfectly okay to lie to you as long as they're "doing it for your own good." Pretty soon, you can start to see that your view of the world may very well be a copy, of a copy, of a copy, each one a little fuzzier than...