In the Islamic sphere most philosophers and theologians rejected the eternity thesis, often on the basis that an eternal world would need no creator.2 But the terms of the debate changed when Avicenna showed a way to affirm both the createdness and the eternity of the universe. He explained that if something is “contingent,” that is, in its own right capable either of existing or of not existing, then it would need an external cause to make it exist. Contingent
