Imam Khomeini (ra) has proven existence of a Creator through this highly logical reasoning. It does not rely on any thing else except pure logic. "It is intellectually clear and every body knows it intuitively that anything the existence and non-existence of which is equally possible, cannot come into existence automatically and that there must be an external force to bring it into existence. The first cause of bringing into existence all possibly existing things must be an eternal and self-existing being. If it is supposed that the imaginary upper space, and it must be imaginary because it is a non-entity, has always existed, then it possibly can neither automatically turn into anything nor anything can come into existence in it automatically. The assertion of some people that in the beginning the whole world was an infinite vacuum (anything being infinite is questionable in itself) in which subsequently appeared a sort of steam from which everything has originated, does not stand to reason, for without an external cause no new thing can appear nor can one thing change into another thing. For example, water does not freeze nor does it boil without an external cause. If its temperature remains constant and does not go below 0 degrees nor above 100 degrees it will always remain water. In short, the existence of an external cause is essential for every change. Similarly nothing the existence of which is only possible can come into existence without an external cause. These facts are self-evident truths."