The Cosmological Argument
Gordon H. Clark
Thomas Aquinas rejected the Platonic cast of Augustine’s theology and based his thought on Aristotle. Therefore he had no time for the ontological argument, but reconstructed the cosmological argument. To refer again to the question of knowledge, the difference between these two arguments is basically a difference in epistemology: For Augustine it was not necessary to start with sensory experience, for one could go directly from the soul to God; but Aquinas wrote, “The human intellect …. is at first like a clean tablet on which nothing is written” (Summa Theologica I, Q:97, 2). It is sensation that writes on the tabula rasa. The mind has no form of its own. All its contents come from sensation. On this basis, Thomas gave five arguments for God’s existence; but the first four are almost identical, and the fifth is so little different, that only the first will be reproduced here:
The first and more manifest way is the argument from motion. It is certain and evident to our senses that in the world some things are in motion. Now, whatever is moved is moved by another, for nothing can be moved except it is in potentiality to that towards which it is moved; whereas a thing moves inasmuch as it is in act. For motion is nothing else than the reduction of something from potentiality to actuality. But nothing can be reduced from potentiality to actuality, except by something in a state of actuality. Thus that which is actually hot, as fire, makes wood, which is potentially hot, to be actually hot, and thereby moves and changes it. Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects. For what is actually hot cannot simultaneously be potentially hot; but it is simultaneously potentially cold. It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e., that it should move itself. Therefore whatever is moved must be moved by another. If that by which it is moved be itself moved, then this also must needs be moved by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and consequently no other mover, seeing that subsequent movers move only inasmuch as they are moved by the first mover; as the staff moves only because it is moved by the hand. Therefore it is necessary to arrive at the first mover, moved by no other, and this everyone understands to be God.