ABSTRACT
The Kalam cosmological argument tries to show that the world has a beginning, caused by God. The roots of the argument are in medieval Islamic philosophy, but in years it has been developed by the American philosopher of religion William Lane Craig. The hope is that people can use the Principle of Sufficient Reason to argue that God is the sufficient reason for the existence of contingent things. Craig considers a tree of possibilities and prunes off the branches that don't lead to God. Craig argues that infinite collections of actual things or events would lead to absurdity and that such collections are therefore impossible. If this argument is sound, the world must have had a beginning. To understand Craig's defense of the premise, people need to say a bit about the mathematical theory of infinity. The concept of infinity is subtle, and if actual infinities exist, some surprising things are true of them.
