Aquinas' Cosmological Arguments The cosmological argument for the existence of God, as proposed by Thomas Aquinas, is also known as the Third Way. It is the third of the five paths of Aquinas' masterpiece, "The Somme" (The Five Ways). The five paths are: the still mover, the causeless cause, possibility and necessity, goodness, truth and nobility and the last path, the teleological. The first three “ways” are different variants of the cosmological argument. The cosmological argument develops around a distinction between that which has necessary existence and that which is contingent. Anything that has a necessary existence must exist in all possible worlds, whereas a contingent being can disappear. The method used by Aquinas is to establish the contrary position and then prove it false. Therefore, cosmological argumentation begins by accepting the postulate that all things are contingent. If all things are contingent, that is, if all things can disappear and do not necessarily exist, then there must be a time when all things disappear. The basic idea is that everything has a prior cause, but the chain of causes cannot go back infinitely far, so there must be a first cause. The “first way” (stationary engine) argument could be summarized as follows: 1. Some things change. (Empirical principle, verified by observation)2. Everything that changes is caused to change by something else. (Aquinas has a separate argument for this)3. The chain of causes cannot go back to infinity.4. Therefore, there must be a cause of change that does not itself change. Premise 2, that not everything that... middle of paper ... has a coherent meaning. Any being claimed to exist may or may not exist. Hume stated this by saying that “all existential propositions are synthetic.” He believes that all claims about existence need proof. He thinks that if "to be necessary" means only "to be imperishable", then the universe itself may be necessary. This is similar to Russell's view in this debate with Copleston. Hume also thinks that no proposition about existence can be logically necessary. The opposite of any statement about experience is always perfectly possible. This may be based on confusion, because Aquinas does not claim that the existence of God is logically necessary – rather, he claims that the existence of God is necessary given motion, cause, and contingency. God is not logically necessary – God is de re necessary, necessary in itself.