One way of arguing for the existence of God begins with the question, "Why is there something rather than nothing?" If we think about the particular entities that make up the world, we can easily see that each of them might never have existed; this is true of all the objects and people around us, the planet on which we live, and the rest of the present and past universe, including its fundamental constituents and the "singularity" (if there was one) from which it all came. Since each person or thing might never have existed, it is reasonable to ask why each of them (and the totality of them) does exist. Ordinarily, we explain the existence of things by noting their dependence upon other entities and processes in the world (e.g., we explain children by parents). At each step in such an
explanation, however, the question "Why?" can be asked again, and a further explanation
is needed. This regress of explanation can come to an end only in a being whose existence
is not dependent upon anything else but rather is independent and necessary.
This informal line of reasoning has led to the following philosophical argument for the
existence of God.
1. Every being is either contingent (i.e., dependent upon other things for its existence) or
necessary (i.e., self-existent).
2. The existence of a contingent being can be explained only by appeal to a cause outside
itself.
3. If we explain the existence of a contingent being in terms of some other contingent
being, then the latter also needs an explanation.
4. This regress of explanation must end at some point.
A) An infinite regress of explanation in terms of contingent beings does not provide a sufficient reason for any contingent being.
B) This would violate the principle of sufficient reason, i.e., that "there is some
explanation of the existence of anything whatever, some reason why it should exist rather
than not" (Taylor, "The Cosmological Argument," p. 26).
5. The regress of explanation can come to an end only in a being whose existence is not
contingent upon anything else (i.e., a necessary being).
6. There is a necessary being, and this we recognize as God.