 Avicenna explains the superiority of a highest type of efficient cause as follows: Where something is such that, whenever it exists, it produces the existence of something else by virtue of its own essence, and where its effect exists after absolute nonexistence and is permanent, then that thing has a higher claim to causality than other things. For such an efficient cause entirely prevents the nonexistence of its effect; it gives complete existence to the effect (Avicenna MH: 203; Marmura 1984).