“Certum est quia impossibile est” is a Latin phrase that is credited to the Christian theologian Tertullian. Translated into English, it means “It is certain because it is impossible.” Tertullian used this phrase to convey the concept that some elements of Christian doctrine may seem impossible or contradictory to human reasoning, but they are believed to be true through faith. Essentially, it emphasizes the notion that faith often requires believing in things that go beyond human comprehension or go against the laws of nature.