Anthropic Bias explores how to reason when you suspect that your evidence is biased by "observation selection effects"--that is, evidence that has been filtered by the precondition that there be some suitably positioned observer to "have" the evidence. This conundrum--sometimes alluded to as "the anthropic principle," "self-locating belief," or "indexical information"--turns out to be a surprisingly perplexing and intellectually stimulating challenge, one abounding with important implications for many areas in science and philosophy.

There are the philosophical thought experiments and paradoxes: the Doomsday Argument; Sleeping Beauty; the Presumptuous Philosopher; Adam & Eve; the Absent-Minded Driver; the Shooting Room.

And there are the applications in contemporary science: cosmology ("How many universes are there?", "Why does the universe appear fine-tuned for life?")

evolutionary theory ("How improbable was the evolution of intelligent life on our planet?")

the problem of time's arrow ("Can it be given a thermodynamic explanation?")

quantum physics ("How can the many-worlds theory be tested?")

game-theory problems with imperfect recall ("How to model them?")

even traffic analysis ("Why is the 'next lane' faster?").

Anthropic Bias argues that the same principles are at work across all these domains. And it offers a synthesis: a mathematically explicit theory of observation selection effects that attempts to meet scientific needs while steering clear of philosophical paradox.