Thomas Aquinas' Five Ways are his arguments supporting the existence of God. In his Second Way, he explores the Argument from Causation. Aquinas' concluded in general observation that everything in the universe is causal to something else. In other words, everything that exists has been created by some other thing. Aquinas also believed that there had to have been an uncaused first cause, which he called God. Through his theory Aquinas states that there is nothing that is the efficient cause of itself, because that would mean that it came before itself, and that is not possible, no matter how one looks at it. He also states if one tries to proceed to infinity looking at causal factors, one will never find the beginning,. Therefore there will be no first cause, and if there is no first cause, there will be no final effect, which Aquinas' states is clearly false. He thinks that it is necessary to assume there is a first cause, an uncaused cause, which we call God.
I think that although Aquinas' Five Ways are persuasive, there are no solid statements that prove, without a doubt, the existence of God. For example, in his first way,
The Argument from Change, he theorizes that the "unmoved mover is God, but there are many proven facts biologically that show energy and muscles and the body it what moves a person. For the time period, it is a conclusive argument and it makes sense that it was supported.