For everything which happens presently is a consequence of something which happened before it. The past, in this sense, is little more than a record of causes and their effects. This record is vast but finite, like the universe itself. When a machine is built powerful enough to crunch the numbers, the only thing left to the historian will be to hire a physicist, mathematician, or programmer to invent an algorithm with enough subtlety to decode the record. Truth then will be just a matter of finding the right graphical interface. And we shall realize that privacy, like prophecy, was simply a fashionable conceit.