The reason the first argument for the existence of God that we will look at is called the cosmological argument is because it begins by looking at the 'blueprint' of the universe and then goes on to conclude that the nature of the universe suggests that there must be a God. The cosmological argument is sometimes referred to as the 'causal argument' or the 'first cause argument' and this should give you some indication as to what is at the heart of the argument. Between the tenth and twelfth centuries, Muslim philosophers residing in Spain, which was part of the Muslim empire at the time, dominated the scholastic debate. The Christian theologian and philosopher St Thomas Aquinas was a product of the scholastic movement, and it is worthwhile spending some time on him because he presents the most famous version of the cosmological argument.