Explain St. Thomas Aquinas’s cosmological proof for God’s Existence
In his monumental works, Summa Theologica and Summa Contra Gentiles, Aquinas offered a total of five proofs of God’s existence. The first two proofs begin with an observation about the physical universe. They are called a kind of cosmological argument because they result from a study of the cosmos. Much of Aquinas version of the cosmological argument was borrowed from Aristotle. Aquinas’s cosmological argument consists of his first 2 of the 5 proofs for God’s existence, or the “Five Ways”. His first two ways are two proofs based on logic and observation of nature in proving God’s existence to those who could not accept or believe God on faith alone.
Aquinas’ first way is based on motion. He calls it the most obvious way. This first argument, the Argument from Motion, tries to prove the existence of God as the first mover which is unmoved. Now, it is certain as a matter of sense-observation that some things in this world are in motion. Whatever is in motion, Aquinas states, is moved by something else. So, it is impossible that in the same respect and same manner anything should be both mover and moved. In this, Aquinas means that nothing can move itself. Therefore, if something is in motion, it must have been put in motion by something else, which must have been put in motion by yet another thing, and so on. However, this cannot go on to infinity because there would never have been a first mover and, consequently, no subsequent movers. After all, second movers do not move except when moved by a first mover, just as a stick does not move anything except when moved by a hand. Thus, this leads to the conclusion that there is a first mover which is not moved by anything, and this first mover is what we understand to be God. Summarizing Aquinas’ first way, the argument states that objects are in motion, and if something is in motion, then it m