Anthropic principle

The anthropic principle is a group of principles attempting to determine how statistically probable our observations of the universe are, given that we could only exist in a particular type of universe to start with. 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. It supposedly explains why this universe has the age and the fundamental 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. Anthropic reasoning is often used to deal with the fact that the universe seems to be fine tuned.

The strong anthropic principle (SAP) states that the universe is in some sense compelled 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 (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.