The __anthropic principle__ is the premise that any data we collect about the universe is filtered by the fact that, in order for it to be observable at all, the universe must have been compatible with the emergence of consciousness and sapience life that observes it - wikipedia
In other words, scientific observation of the universe would not even be possible if the laws of the universe had been incompatible with the development of sentient life.
Proponents of the anthropic principle argue that it explains why this universe has the age of the universe and the dimensionless physical constants necessary to accommodate conscious life, since if either had been different, we would not be around to make observations in the first place. As a result, outside the fine-tuned universe it would seem impossible that life (in particular, intelligent life) could develop.
There are two different formulations of the anthropic principle. The __strong anthropic principle__ (__SAP__), as defended by John D. Barrow and Frank Tipler, states that this is all the case because the universe is in some sense compelled to eventually have conscious and sapient life emergence within it.
Some critics of the SAP argue in favor of a __weak anthropic principle__ (__WAP__) similar to the one defined by Brandon Carter, which states that the universe's ostensible fine tuning is the result of selection bias (specifically survivorship bias): i.e., only in a universe capable of eventually supporting life will there be living beings capable of observing and reflecting on the matter.
Most often such arguments draw upon some notion of the multiverse for there to be a statistical population of universes to select from and from which selection bias (our observance of ''only'' this universe, compatible with ''our'' life) could occur.
# See also
- Big Bounce - Boltzmann brain - Doomsday argument - Fermi paradox - Goldilocks principle - Great Filter - Infinite monkey theorem - Inverse gambler's fallacy - Mediocrity principle - Metaphysical naturalism - Neocatastrophism - Puddle thinking - Quark mass and congeniality to life - Rare Earth hypothesis - Triple-alpha process