Explain the Kalãm Cosmological Argument for God's Existence

The Kalãm Cosmological Argument for God's existence was propounded by the medeival Islamic theologian Al-Ghazali (1058-1111), and has recently been revived in modern philosophical discourse through the work of Dr. William Lane Craig. It is a three premise deductive argument for the existence of God, which means that the conclusion necessarilly follows from the first two premises, providing that they are true. It is also an a posteriori ('from the latter') argument, and therefore it appeals to the nature of the universe as observed by humans, rather than pure reason (a priori arguments). In its contemporary form, the argument proceeds in the following manner: (1) Everything which begins to exist has a cause. (2) The Universe began to exist. (3) The Universe has a cause. Advocates of this argument contend that premise 1 is correct, because everything we observe comes to exist because it has been caused to exist by something prior. Premise 2 is supported by the impossibility of an infinite regress of events, and certain scientific models of the early universe (such as the Big Bang theory), which suggest that the universe began to exist. And the conclusion then follows from these premises. The cause of the universe is understood to be something which transcends the universe itself (i.e. God), because the universe could not bring itself into existence - to do this, it would already have to exist!...