What is the final cause?
The final cause is the purpose for which the object was created. St. Thomas further explains: "Matter does not acquire form, except according as it is moved by the acting cause (agent); for nothing reduces itself from potency to act. But the acting cause does not move, except by reason of the intention of an end." (Catholic Encyclopedia/Cause) For example, when I bite into an apple I first use my front teeth because they were made in order to cut. Only after I cut food into smaller piece do my grinding teeth come into play. In order words, there is a reason why my front teeth were created thinner. Unfortunately, "The idea that organisms have a purpose/telos is totally foreign for most contemporary evolutionary biologists. Teleological language is deliberately avoided because of the commitment to an unguided process of evolution." (wordpress.com/Rethinking Aristotle: The unwanted Rejection of 'Final Causation' in the Modern Evolutionary biology)
One might say that the final cause of living things in nature is "to be what they are". The final cause of an apple tree is to be an apple tree; the final end of the tiger is to be a tiger. In other words, the final cause is identified with the form or nature it has. This, however, fails to ask what the final reason for nature as a whole is. The final cause of nature as a whole is transcendence which means that lower forms of being are to live is the higher forms (matter is for plants, plants are for animals, animals are for man and man is for God). The final reason why all things are created and dynamically function is ultimately to participate in God's life, in some way, or to give glory to God.
God who stands at the origin of the universe must also be its end because he is the reason for which all creatures exist. I ask you, "Why were you created?" Many cannot answer this question because they do not know or understand God's revelation. God the Father created man to participate in his unending life of glory, that is to be happy forever. The Father desired this to be accomplished through his Son by the power of the Spirit. This would have been the case even if man had not sinned which deprived him of God's glory. And so, the role of Christ became that of the Savior, or shall we say that in the foreknowledge of God, Christ was always the Savior. The Father brought about our justification through his Son's nature which was both divine and human. He is the Way into the Father's glory by the power of the Spirit who raised him from death. He who has no beginning and end became our beginning and end most appropriately in and though his Son who is both God and a Creature. This is why Christ said or himself, "I am the Alpha and the Omega, the first and the last, the beginning and the end. (Rv 22:13) He is symbolized by the first and last letters of the Greek.