http://santitafarella.wordpress.com/2013/07/26/why-i-am-an-agnostic-and-not-an-atheist/

As Thomas Aquinas formulated it, I think the first cause argument is sound. To stop the infinite regress, there must be a first cause that has no cause and a first condition that has no conditions, and, as Aquinas puts it, “We call that God.”