After the fall of Rome, most of the works of the Greek philosophy were lost to Western Europe. However, Islamic scholars had saved many of these works found in Byzantine libraries and other libraries in the ancient world, such as Alexandria, where Ptolemy work in 200CE. Later, Islamic scholars, such as Avicenna between 980-1037 and Averroës between 1126-1198, as well as the Jewish scholar Moses Maimonides between 1135-1204 helped re-introduce these works. By the 12th century, these translated works had made their way back into Europe. Aquinas was to use the work of Aristotle to justify his beliefs, which separates him from earlier Christian philosophers. Aquinas tried to base his view of God and of the world, on what men could learn about the world through rational reasoning.
Thomas Aquinas was born in 1224 into an aristocratic family living in Roccasecca, Italy. He was to eventually become one of the most acknowledged Christian philosophers in history. Aquinas' education began at a Benedictine monastery, but he went on to study at the University in Naples, receiving his degree in 1244 at the age of 20. He continued his study of philosophy and theology under the tutelage of the Dominicans in Paris and Cologne and, in 1256, received his doctorate in theology. For the next 10 years, Aquinas spent time in various Dominican monasteries near Rome, lecturing on philosophy and theology. However, his special interest was the philosophy of Aristotle. His greatest work was the `Summa`, which he worked on from 1265 until his death in 1274. Much later, in 1879, Pope Leo XIII recommended that St. Thomas Aquinas' philosophy be made the basis of instruction in all Roman Catholic schools. Subsequently, in 1950, Pope Pius XII affirmed that the `Thomist` philosophy was an official guide to the Roman Catholic doctrine.
The `Summa Theologiae` and the `Summa Contra Gentile` were Aquinas' most famous works on Christian philosophy. However, much of this work was centred on one question:
How can we reconcile faith and reason?
According to Aquinas, man, as an animal, may only know what he experiences through his senses, i.e. empiricalism. However, a being, endowed with reason, can learn to understand the universe beyond the senses, i.e. rationalism. If you extend this argument, you arrive at one of Aristotle's guiding principles, i.e.
Whatever exists can be understood and must have a rational cause.
Understanding the principle of causation, which ultimately leads to the first cause, was considered the primary object of knowledge. During the course of his life's work, Aquinas developed the details, which supported his view of Christianity and Aristotelian philosophy. As indicated, this philosophy would, in 1879, be accepted as an official doctrine of Roman Catholic theology. Although Aquinas wrote much on the works of Aristotle, the Summa Contra Gentiles, written between 1259 and 1264, and Summa Theologica, written between 1265 and his death in 1274, represents the pinnacle of his philosophical thinking. However, the aspect of his work of greatest interest to our immediate discussion are his views on the nature of god, especially the rationalism behind his five-way proof of god's existence using Aristotelian logic:
- First Way: The Argument From Motion
An object in motion is put in motion by some other object or force from which it is concluded that there must ultimately be an unmoved mover, i.e. God, who first put things in motion.
- Second Way: Causation Of Existence
No object creates itself and therefore some previous uncaused first cause, i.e. God, is required to begin the chain of existence.
- Third Way: Contingent and Necessary Objects
There are two types of objects in the universe, i.e. contingent beings and necessary beings. A contingent being is an object that cannot exist without a necessary being, i.e. God, causing its existence.
- Fourth Way: The Argument of Degrees And Perfection
Given two objects, one may be said to have a greater degree of beauty than the other, which is referred to as degree or gradation of quality. For any given quality, e.g. goodness, beauty, there must be a perfect standard by which all such qualities are measured. This perfection is contained in God.
- Fifth Way: The Argument From Intelligent Design
Observation tells us that the universe works in such a precise way that one must conclude that is was designed by an intelligent designer, i.e. God. Therefore, God is the intelligent designer, who designed all physical laws and the order of nature and life.
Note: While accepting the logic of Aquinas' arguments, we might still consider the nature and intelligent of Aquinas' God - see Probability of God.
However, the most important thing to remember when reviewing Aquinas' proof is that he was, at least, trying to provide a rational explanation for the existence of God. In the context of the time, most religious doctrine would simply have accepted the existence of God as a principle of faith. In contrast, Aquinas was attempting to reconcile his faith with reason. Of course, Aquinas is still a believer of the Christian doctrine and therefore believes that some mysteries can only be understood through divine revelation. Only matters of physical `substance` can be understood by rational experience. It is this premise that Aquinas sets out in his proof for the unity, timelessness, infinity and goodness of a perfect being, i.e. God. Although it is accepted that the explanation of Aquinas's five-way proof above is, but the briefest of summary of a voluminous work, it is possible that the essential arguments can be reduced still further. It appears that the first three ways are, in essence, re-iterations of one question:
Who created the universe?
- In the absence of any deeper empirical truth, the theological
concept of `God` seems merely to replace the philosophical
concept of the 'first mover` or 'first cause'
or even Aristotle's `prime mover`. However, it is not
clear how this really provides proof.
- Again, Way-4 introduces no additional empirical evidence and
so may only be making a subjective assumption about the character
of God, i.e. God is perfection. Presumably, God is either not responsible
for the imperfection or cruelty in the world or works in ways too
mysterious for us to understand.
- Finally, Way-5 simply seems to be the natural corollary of the first three, i.e. having made the assumption that God created the universe, it only seems reasonable to assume that he gave some thought to its design. Of course, the validity of Way-5 remains dependent on the validity of ways 1,2 & 3.
Although Aquinas extends faith to encompass rational thinking, he does not really embrace empirical verification in support of his proof. By his argument, animals have empirical senses, but only a being is endowed with reason that can understand the wider universe. There are undoubtedly aspects of Aquinas' universe, which transcend our physical reality and therefore may transcend empirical verification. However, any philosophy, even a rational one, which is only supported by circumstantial evidence, cannot really prove whether its rational arguments are, in fact, true. As such, whether Aquinas' 5-way proof is based on faith or a rational philosophy, it also remains a speculation. While science permits speculation, it calls such speculations, without empirical evidence, a hypothesis. So while Aquinas may have believed he had reconciled faith and reason, he had not reconciled faith and science.