The idea that the universe was made just for us—known as the anthropic principle—debuted in 1973 when Brandon Carter, then a physicist at Cambridge University, spoke at a conference in Poland honoring Copernicus, the 16th-century astronomer who said that the sun, not Earth, was the hub of the universe. Carter proposed that a purely random assortment of laws would have left the universe dead and dark, and that life limits the values that physical constants can have. By placing life in the cosmic spotlight—at a meeting dedicated to Copernicus, no less—Carter was flying in the face of a scientific worldview that began nearly 500 years ago when the Polish astronomer dislodged Earth and humanity from center stage in the grand scheme of things.

Carter proposed two interpretations of the anthropic principle. The “weak” anthropic principle simply says that we are living in a special time and place in the universe where life is possible. Life couldn’t have survived in the very early universe