Reality is not digital, an on-off state, but analog. Something gradual. In other words, reality is a quality that things possess in the same way that they possess, say, weight. Some people are more real than others, for example. It has been estimated that there are only about five hundred real people on any given planet, which is why they keep unexpectedly running into one another all the time.
– Terry Pratchett, Moving Pictures
Damn the running into one another. If this is true, the more profound implication is that the five hundred real people are all sleeping with each other.