St. Thomas Aquinas Third Way Modalized :: Aquinas Third Day Philosophy Papers

Aquinas ternary trend ModalizedABSTRACT The Third Way is the roughly interesting and insightful of Aquinas five arguments for the existence of God, even though it is invalid and has some false premises. With the help of a somewhat weak normal logic, however, the Third Way can be transformed into a argument which is certainly valid and plausibly sound. Much of what Aquinas asserted in the Third Way is possibly true even if it is not actu everyy true. Instead of assuming, for example, that things which are contingent fail to exist at some epoch, we need only develop that contingent things possibly fail to exist at some time. Likewise, we can replace the assumption that if all things fail to exist at some time so there is a time when nothing exists, with the corresponding assumption that if all things possibly fail to exist at some time then possibly there is a time when nothing exists. These and other similar replacements suffice to produce a cogent cosmological argument. Aquina s Third Way is a cosmological argument for the existence of God which is taken from possibility and necessity. It is surprising therefore that philosophers of religion have not shown much interest in applying modal auxiliary verb logic to its analysis. (1) There are a couple of reasons. First, Aquinas does not always use the words possibility and necessity in the same way that they are use in modal logic. Second, cosmological arguments generally purport to word form a bridge between some property of this world and a supreme being, making it unnecessary, it might be thought, to appeal to modalized features of other possible worlds.Modal logic has of course been applied extensively to the analysis of ontological arguments. Ontological arguments purport to build a logical bridge between thought and a supreme being. Most ontological arguments proceed from the assumption that it is possible for God to exist. They then tie beam this assumption with some rather strong and controversial p rinciples of modal logic in order to prove that God must exist in all possible worlds, from which it follows that God exists in the real world. (2) It might be possible, however, to prove the existence of God with the use of a weak and noncontroversial system of modal logic if we root the proof with some plausible possibilistic principles about what might be true of the cosmos. The Third Way is not sound per se.