Aquinas' First Argument, Motion
(1) Objects are in motion.
(2) If something is in motion, then it must be caused to be in motion by
something outside of itself.
(3) There can be no infinite chain of movers/movees.
(4) So there is a first, unmoved mover.
(5) Therefore, God exists.
Aquinas' Second Argument, Causality
(1) Some events cause other events.
(2) If an event happens, then it must be caused by something outside of itself.
(3) There can be no infinite cause/effect chains.
(4) So, there is a first, uncaused cause.
(5) Therefore God exists.
Aquinas' Third Argument, Contingency
(1) Contingent things exist.
(2) Each contingent thing has a time at which it fails to exist (contingent
things are not omnipresent).
(3) So, if everything were contingent, there would be a time at which nothing
exists (call this an empty time).
(4) That empty time would have been in the past.
(5) If the world were empty at one time, it would be empty forever after (a
conservation principle).
(6) So, if everything were contingent, nothing would exist now.
(7) But clearly, the world is not empty (premise 1).
(8) So there exists a being who is not contingent.
(9) Hence, God exists.
Aquinas' Fourth Argument, Properties That Come
in Degrees
(1) Objects have properties to greater or lesser extents.
(2) If an object has a property to a lesser extent, then there exists some
other object that has the property to the maximum possible degree.
(3) So there is an entity that has all properties to the maximum possible
degree.
(4) Hence God exists.
Aquinas' Fifth Argument, From Design
(1) Among objects that act for an end, some have minds, whereas others
do not.
(2) An object that acts for an end, but does not itself have a mind, must have
been created by a being that has a mind.
(3) So there exists a being with a mind who designed all mindless objects that
act for an end.
(4) Hence, God exists.
Anselm's Argument, The Ontological Argument
(1) God is by definition the greatest possible being.
(2) A being who fails to exist in the actual world (while existing in other
possible worlds) is less perfect than a being who exists in all possible
worlds.
(3) Hence, God exists, necessarily.
* I would like to
say that these were originally my own work, but I collected these over many
years and regret that I cannot find a reference to an original author. RJS