As a Dominican monk, Thomas Aquinas (1225-1274) spent most of his life aligning the dogma of the Roman Church with Aristotelian philosophy. Catholic dogma at that time consisted of a host of metaphysical ideas, particularly those held by Saint Augustine (354-430). Aquinas battled with the Averroist claim that philosophy and divine revelation were independent of one another.
Like the Averroists, Aquinas argued that all sensation comes through the senses; BUT unlike them, he claimed that it the human intellect raises man to make sense out of incoming sense data so that we know the substance of things. In the same manner, our intellect coupled with what has been divinely revealed elevates us to interpret higher truths including the existence of immaterial substances such as angels, our inner souls, and God. Thus, philosophy depended on Divine Revelation for guidance. Because of his quiet, rather stout appearance, Aquinas was sometimes referred to as The Dumb Ox.
1) To Aquinas, proving the existence of God was elementary. He argued that because we see things in motion, each must have had a mover or it would be standing still. The prime mover-God.
2) His second argument is one of causation. Nothing can be the cause of itself. Thomas reasons that a being must exist that puts things into existence. This initial cause-God.
3) We find in our every day world things that corrupt and pass away. People and objects exist in a certain form but after a time, they change and ultimately pass away. Everyday experience tells us this. The force which keeps things from falling back into non-being-God.
4) In the world we notice qualities in things which are more or less perfect, particularly where morals are concerned. Aware of the less perfect, we are immediately aware of what is more perfect, particularly in the realm of evil and/or good. Our awareness hints of the most perfect good-God.
5) Inanimate objects, such as celestial bodies, could not have prearranged themselves into orbits aligned in such a way that our planet is able to exist harmoniously among them. Although man is an intelligent being, still, he is unable to move planets. The infinite designer-God.
If he were alive today David Hume would probably find Aquinas’ philosophy almost laughable. Why? Here my personal prejudice kicks in although I am not a Roman Catholic. Aquinas looked out at his world with a certain common sense about reality. David Hume looked out at his world as if he needed glasses, badly.
Unlike Thomas Aquinas, David Hume had a real problem with causality. A problem that influenced his life, his thinking, and his followers. Hume has sometimes been referred to as the absolute skeptic.
Let’s suppose Hume is alive and using public transportation. He is standing at a T station awaiting a transit train to take him into downtown Pittsburgh. The T is the name of Pittsburgh’s partially underground rapid transit system. During high traffic hours, there are four cars joined together to make up a train operated by a driver who sits in the very front of the train.
A four car train approaches the station, Hume becomes preoccupied with the cars and their connections. He asks the driver, “Pardon me, but can you tell me if this car is pulling the other cars, or are they pushing it?”
The driver replies, “Listen buddy, do you want to ride or not?” Hume looks confused and remains stiffly in place. Quickly, the doors shut and the four cars start to pull away. Hume is left standing on the platform. Intently, he watches the passenger cars roll past, one by one, but he looks at the couplers between the cars to see if there is not some way of determining why the other cars are moving.
David Hume had a real problem with issues of causality. He searched in vain to hunt what it is that people witness as causality. In the episode above, there was no way for him to know whether the first car was the engine pulling the others along. Maybe it was the second car pushing the driver’s car along and at the same time pulling the other two behind it. Possibly it was the last car, pushing all of the other cars ahead.
Hume stated that since we cannot see whatever-it-is that transfers from one object to another when it is pushed or pulled, we can never be certain about cause or effect. Because a bowler rolls a ball toward the ten-pins one time does not mean it will roll away from her/his hand the next time. We merely assume it will. Yet we can never really be sure because the invisible whatness that tranfers from the bowlers hand to the ball is invisible. Since Hume could not locate it, he assumed it was merely a mental construct or non-existent.
His philosophy brings up another issue. How can science possibly lead to proven conclusions? For example, there was a time when everyone believed in a fixed or stagnant universe. Common belief held that the stars and planets were out there fixed in their spatial orbits. Astronomers, the Hubble telescope, and the red shift have proven that the universe is not stagnant. It is moving relentlessly outward. Discoveries are constantly bursting the paradigm of science. So Hume would ask, if we cannot be certain about our sense observations, how can we ever be sure of anything?
So after a very brief comparison of the ideas of these two men about causality, which is the most laughable? Is it Aquinas who used a common sense approach to reality? Is it David Hume who had much difficulty mentally leaping the gap from uncountable observations to general scientific conclusions?
Hume’s ideas are mental paradoxes which can haunt the mind. They are fun to think about and even more fun to try to discredit if that is even possible. But I cannot help wondering if Hume was alive today and needed glasses, would he wear them each day, or reject them after one successful trial saying, “How do I know they’ll work for me next time?