The anthropic principle is the philosophical consideration that observations of the physical universe must be compatible with the conscious and sapient life that observes it.

The strong anthropic principle (SAP) states that this is all the case because the Universe is compelled, in some sense, to eventually have conscious and sapient life emerge within it.

The weak anthropic principle (WAP) states that the universe's ostensible fine-tuning is the result of selection bias, i.e. only in a universe capable of eventually supporting life will there be living beings capable of observing and reflecting upon any such fine-tuning, while a universe less compatible with life will go unbeheld.