The empirical fact of the big bang has led some theists to argue that this, in itself, demonstrates the existence of a creator. In 1951 Pope Pius XII told the Pontifical Academy, “Creation took place in time, therefore there is a Creator, therefore God exists.”9 The astronomer/priest Georges-Henri Lemaitre, who first proposed the idea of a big bang, wisely advised the pope not make this statement “infallible.”