Anthropic Bias: Observation Selection Effects in Science and Philosophy (2002) is a book by philosopher Nick Bostrom.

He later refines SSA into the strong self-sampling assumption (SSSA), which uses observer-moments instead of observers to address certain paradoxes in anthropic reasoning.

[5] Bostrom, in his book Anthropic Bias: Observation Selection Effects in Science and Philosophy, has suggested refining SSA to what he calls the strong self-sampling assumption (SSSA), which replaces "observers" in the SSA definition by "observer-moments".

[6] Bostrom argued against the SIA, as it would allow purely a priori reasoning to settle the scientific question of whether the universe is infinite/open rather than finite/closed.

[5] A review from Virginia Commonwealth University said the book "deserves a place on the shelf" of those interested in these subjects.