1) What is the nature of the universe?According to Thomas Aquinas, the great theologian and author of Summa Theologica, the nature of the universe may be explained using the following five aspects, namely, motion, an order of efficient cause, necessity and possibility, gradation among things, and governance by the intelligent Almighty. As stated in the text, "In the world some things are in motion." And "...whatever is in motion is put in motion by another." The author's claim here is that for things that are in motion to be transformed to a state of actuality from one of potentiality, movers are needed, with the First and Decisive Mover being God. Secondly, the author states that: "In the world of sense we find there is an order of efficient causes." In other words, all things in the universe are caused by another, with the very first efficient cause being God. Thirdly, in the following statement in the text, "We find in nature things that are possible to be and not to be, since they are found to be generated, and to corrupt, and consequently, they are possible to be and not to be," the author explains, with regard to the universe's nature, that all entities in the universe, with the exception of God, cannot always exist. Furthermore, with regard to the nature of beings in the universe, "... there are some more and some less good, true, noble and the like." The author asserts that all perfection and goodness in the universe is seen to varying degrees among God's creation, with the maximum goodness and absolute perfection present in none but the Creator. Lastly, again with respect to the nature of the universe's entities, the text explains that: "Things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result," and, following from the above quote, "Nature works for a determinate end under the direction of a higher agent. Aquinas implies that an intelligent being -- the Almighty...

The higher agent referred to here is God.
2) What is the nature of man?

The author of Summa Theologica argues about the nature of human beings, in particular, among the universe's entities, that: human beings recognize the presence of an entity that is greater than all else in the universe, and have labeled this entity -- "God." To quote the text, "Granted that everyone understands that by this word "God" is signified something than which nothing greater can be thought, nevertheless, it does not therefore follow that he understands that what the word signifies exists actually, but only that it exists mentally." However, we all have a different perception of God in our mind's eye and not all of mankind believes that God actually exists. For some, God is only a Power existing within the mind. Aquinas further expounds on this by stating, "To know that God exists in a general and confused way is implanted in us by nature, inasmuch as God is man's beatitude." By this, the author of Summa Theologica wishes to explain that human nature, although accepting of the presence of an entity greater than all of creation, is not always clear on the concept of God. The concept of God is entrenched in our nature but not everyone has a clear idea of Him. Everybody does have a vague and general idea of Him, though. Furthermore, "There is nothing to prevent a man, who cannot grasp a proof, accepting, as a matter of faith, something which in itself is capable of being scientifically known and demonstrated." In other words, any concept in the universe which is true but beyond the understanding of man is categorized by him as an element of faith. An individual incapable of comprehending scientific, evidenced facts conveniently labels certain complex concepts, like the existence of God, as "faith." Lastly, Thomas Aquinas is also of the opinion that "Human reason or will... can change or fail."…