The ways of demonstrating the existence of God formulated by Aquinas (Summa Theologiae, Ia 3: it is important in understanding the significance of these arguments to Aquinas that the entire context stretches from Ia 2 to 11). They are: (1) Motion is only explicable if there exists an unmoved, first mover; (2) the chain of efficient causes demands a first cause; (3) the contingent character of existing things in the world demands a different order of existence, or in other words something that has a necessary existence; (4) the gradations of value in things in the world require the existence of something that is most valuable, or perfect; (5) the orderly character of events points to a final cause, or end to which all things are directed, and the existence of this end demands a being that ordained it. All the arguments are physico-theological arguments . The second is a first cause argument, and the first is the Aristotelian variety of it (accepted by Averroës ) that singles out the causes of motion as particularly in need of a starting-point (see mover, unmoved ). The third is a variety of the cosmological argument, as it had been formulated by Avicenna (but rejected by Averroës). The fourth is the degrees of perfection argument . The fifth is a version of the argument from (or to) design.
Philosophy dictionary. Academic. 2011.