When non-Christians and anti-Christians ask that God does not exist and Bible is merely a book, how do Christians answer to them and what should Christians say? Christians are in difficulties to explain God, Bible, and salvation to secular people, because belief of Christians is based on the Holy Bible, which seculars do not believe in, and because Christians do not like explain these thing through secular ways, such as science and philosophy. At this point, there is big gap between Christians and non- and anti-Christians. Christians want to explain their belief from, in, and through the Bible, but secular people do not want to listen to the Bible. Christians do not want to cover their belief with secular techniques, but secular people pay attention to explain these through secular methods.
For example, according to Kingdom Triangle by J.P. Moreland, scientific naturalism has challenged Christianity and religious belief with four arguments. These arguments are that 1) religious belief is not scientific, 2) religious belief is unprovable, 3) religious belief is unsupported by evidence, and 4) religious belief is superfluous. Furthermore, according to the Ethics of Belief written by a nineteenth-century mathematician named W.K. Clifford. He said, "Anyone who accepts a religious belief is guilty of acting immorally, irresponsibly, and irrationally." According to Faith beyond Reason by C. Stephen Evans, he explains the circumstance of thoughts about faith.
There is probably no word in the English language that is more complex and is used in more different senses than the word 'faith'. Religious faith is a concept that both friends and opponents of religion often misunderstand. Thus, the 'free-thinking' critic of religion alleges that religious belief is not backed up by evidence, but is held solely 'by faith'. The critic may mean by this simply that such beliefs have no support at all, but are something like a personal choice made for no good reasons. Embattled religious believers who have no answer for the secptic may embrace the same impoverished view of faith, thus relieving themselves of any need to think about their beliefs.
Do Christians have any solution of this gap of thoughts between Christians and non- and anti-Christians? Do Christians must wait until one day that secular people become Christians by receiving the supernatural grace from God? Christians know the answer is no. Christians must answer the question whether God exist or not, by something that secular people want. Some theologians tried to make a bridge between them by using the philosophical methods. Some hated to be explained their theology and the God by philosophy. Some put theology onto philosophy, and they opened a little gate of mind. Obviously, Christians will find some solution from the synthesis of Thomas' philosophy and theology in his achievements.
Relation between Philosophy and Theology in the history
Many theologians tried to systematize the relationship between theology and philosophy, and the relationship is characterized into four forms. The first form is that faith is superior to reason, the second is that reason is superior to faith, the third is to pursuit harmony between faith and reason, and the forth is to assert disconnection between them .
Faith priority people oppose the reason of people, and only use the Bible, revelation, and faith. The reason why the people conflicted to the reason is that there are big risks of using reason to theological foundation and faith. Philosophy itself has error, and there is the limitation of philosophy having error. The group believed that if theologians use reason having error to explain revelation, revelation would be not revelation, and revelation loss its characters. For instance, even though Aristotle maintained the first mover, he accepted polytheism and he did not believe in the Creator God. The theologians who asserted faith priority were Tertullian.
"What indeed has Athens to do with Jerusalem?" This question of the relation between reason, here represented by Athens, and faith, represented by Jerusalem, was posed by the church father Tertullian (c.160-230 CE), and it remains a central preoccupation among contemporary philosophers of religion. Tertullian, the early Church Father, exemplifies this sort of attitude in his bitter rejection of philosophy as the source of heresy. In his famous outburst concerning the death and resurrection of Christ: "It is by all means to be believed, because it is absurd....the fact is certain because it is impossible," Tertullian reflects a kind of mentality (never absent in the history of the Church) that despises any attempt to intellectualize the faith.
The reason priority is the idea that unaided human reason discovered all truth.Therefore everything is measured by the reason. A theologian Sieger von Brabant asserted that the philosophy of Aristotle is the best result of the wisdom of human. Revelation must be explained by Aristotle's philosophy, and his philosophy must be the measure of revelation. People could understand the word of God by theological ways, but theology is given allegorical to people and philosophy is given clearly to people. Therefore, Aristotle's philosophy includes the real truth, and theology must be rearranged by the philosophy. Only philosophy could remove the unenlightened minds of people by the philosophy.
Famous rationalists include such individuals as Rene Descartes, Benedict Spinoza, and Immanuel Kant. Rationalism says that everything cannot be detained or explained by reason must be rejected.People's ability measured spirituality and religion."Immanuel Kant succinctly summed up the "reason only" movement with the title of his book, Religion within the Limits of Reason Alone."
Nominalism at 14-15 century expressed their thoughts in disconnection between faith and reason. A nominalist William Ockham raised an objection to the theory of knowledge. Ockham believed that creatures could talk about a Creator when there are similarity between God and human, but because there are no likeness between creatures and a Creator, Ockham denied epistemology of revelation. Therefore, knowing God is only from revelation, if so, reason is almost denied. Some evaluate Ockham:
Ockham is not a radical intellectual separatist who disdains natural reason or regards with suspicion any Christian thinker who wishes to study the works of non-Christian philosophers with the same intensity as the books of Sacred Scripture. In fact, anyone familiar with Ockham's thought knows that he has immense respect for Aristotle and that his theology is marked by (what he believes to be) Aristotelian positions on a wide range of issues in ontology and philosophical semantics....Ockham's is an irenic separatism that rejects the prototypically Catholic intellectual project of unifying classical philosophy and the Christian faith in such a way as to exhibit the latter as the perfection of the former, and yet that stops short of disdaining the light of natural reason in the manner of radical intellectual separatism.... Ockham will always be viewed as something of an outsider both by the radical separatist, who is bent on isolating faith and reason completely from one another, and by the mainstream Catholic thinker, who seeks a genuine synthesis of faith and reason.
Thomas Aquinas and Duns Scotus agree with harmony argument. At this point, harmony between faith and reason emphasized that both of them came from one God.
It is true that the Bible shows some awareness of the fact that not everyone believes in God. Many people are regarded as worshipping false gods rather than the true God, and it is noted that the fool has said in his heart that there is no God (Psalm 14:1). In Romans 1, Paul explains that there is a natural knowledge of God, which is sufficient to make human beings responsible before God, but that this knowledge can be and has been suppressed. The Bible as a whole seems to assume that people are aware of God's reality, or at least that they can be aware of God without any special revelation or philosophical argument.
Moreover, St. Thomas explained why people think either reason or faith is better than another. Thomas accepts both reason and faith as each providing man with knowledge in certain way. They are both God-given faculties, and therefore they cannot ultimately contradict one another. If they seem to do so, it is either because reason has been misused or because faith has misinterpreted God's revelation.
The proper sphere of reason is philosophy, in which man seeks to discover the first cause and final purpose of all his manifold experience, and the departmental sciences in which man seeks to discover immediate causes and how they operate in particular fields. The object and aim of philosophy and the sciences is to discover truth. Now St. Thomas believes that God is Truth and the Source of all truth. Hence all man's efforts to aim true knowledge are really directed towards God.
Thomas Aquinas' Background and Thoughts
Philosopher Aristotle' endeavor about god influenced not only the history of philosophy but also the history of Christianity deeply and widely. Aristotle systematized thoughts about god that previous people had, and he especially developed ideas of god based on the idea of philosopher Parmenides. Many theologians did not have free from the ideas of Aristotle for a long time. For example, Parmenides' term, "unmoved mover", flowed into the idea of Aristotle, and philosopher Aristotle's conception came into the proof of God of theologian Thomas Aquinas.
I take Thomas's relationship to Aristotle to be a complex one, and hardly one of disciple to master. Thomas is surely an admirer of Aristotle and a brilliant commentator on his writings. In particular, he thinks Aristotle more useful for Christian theology than Plato, not least because Aristotle helps him focus on and analyze the concrete particular existing thing, which for him fits well with the Christian ideas of creation and incarnation.
However, even though Aquinas used the thoughts and terms of Aristotle, Aquinas developed Aristotle's things toward Christian things. According to Bauerschmidt, Thomas is not an Aristotelian, because "his strong interest in Aristotle must be balanced by the fact that he draws upon a wide range of thinkers, including the two very different forms of Neoplatonic Christian theology represented by Augustine and by Dionysius the Arepagite, both of whom are pervasive influences on Thomas's writings," because he is willing to change Aristotle both when he conflicts with divine revelation and when Thomas judges him to be philosophically inadequate."
Aristotle and Aquinas have many similar thoughts on the way that the human person should live. Both of them believe that humans are rational beings. They also believe that because humans are rational they can follow their instincts and live a life of moral goodness. Aquinas however, believed that God was leading human beings to a rational, moral life, while Aristotle believed that being moral was naturally inherent in human beings. Although they had different views as to why human beings should want to live a good life, they both agreed that the one thing that humans should strive for is eudaimonia. Aquinas, being an Aristotelian, agreed with many of the ways in which Aristotle viewed the human person. However, where he diverged was his belief in God. He took the teachings of Aristotle and added God to them so that they would allow for more acceptances from our Christian society.
Thomas Aquinas was very wise theologian and philosopher in terms of his attempted to use philosophy to explain the God. Aquinas believed that everything on the earth came from the one God, so the creatures of God showed people Himself. Aquinas took up a positive attitude to use reason, and pursuit the harmony not only between theology and philosophy, but also between faith and reason. In this perspective, Thomas Aquinas tried to prove the existence of God in his book, Summa Theologiae. However, to Aquinas, theology is always better than philosophy and above it. Aquinas did not think that the proof of the existence of God is proving the existence of the Christians God. "Rather Aquinas does this not to prove to the atheist the a God exists but to show that the normal way in which people use the word "God" is not nonsensical...."
In his achievements, Summa Theologiae and Summa Contra Gentiles, there is the proof of existence of God by five ways. The arguments are 1) from motion, 2) from the nature of the efficient cause, 3) from possibility and necessity, 4) from the gradation to be found in things, and 5) from the governance of things. Aquinas used some terms and ideas of Aristotle in his argument. Even though Thomas Aquinas and his proof of existence of God were not perfect, his effort to make harmony between reason and faith, his attempt to meet the ideas of philosophers, and his humility to the Christian God must be honored by Christians who are ignoring reason.
The Five Way and Sources
The First way: Motion
It is certain, and evident to our senses, that in the world some things are in motion. But whatever moves is moved by something else, for nothing can be moved unless it has a potential for that toward which it is moved; whereas something moves inasmuch as it is actual, since motion is nothing other than the transition of something from potentiality to actuality. But nothing can be moved from potentiality to actuality except by something in a state of actuality.
Thomas Aquinas was very much aware of the fact that he was using materials form philosophical tradition. People may think that the First Way's remote origin is Plato's reduction of all movements to a being or form which is essentially movement. However, St. Thomas' argument is directly dependent on Aristotle's demonstration of the existence of the First unmoved Mover, especially in his book, the Physics.
Did motion itself ever come into existence, never having been before? And will it in like manner cease to be, so that nothing will move thereafter? Or did it never begin to be and will it never cease to be, so that there always has been and always will be motion, belonging to all things as their deathless and never- failing property and constituting a kind of life for everything that is constituted by nature? 
If a thing is in motion it is, of necessity, being kept in motion by something. If it has not the source of its motion within itself, then it is clear enough that it is being moved by something. If on the other hand its source of motion is in itself, let AB represent something that is in motion, not accidentally by virtue of some part of it being on motion, but primarily and in itself....The series mist therefore come to an end, and there must be a first moved mover.
The second way: Causality
In the perceptible world we find that there is an order of efficient causes; but we do not find, nor could we find, anything that is the efficient cause of itself, for in that case it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in every ordered series of efficient causes the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether there are many intermediate causes or only one.... Therefore it is necessary to accept some first efficient cause, to which everyone gives the name of God.
People may say that the second way was prepared by Plato's doctrine of the Demiurge that framed the world, and Aquinas seems to ascribe the argument to Aristotle. However, the Second way came to be used by several authors, at least in a less formal manner, such as Cicero, Philo, and Avicenna. Furthermore, Aristotle could hardly demonstrate of God's existence, but Aquinas refrains from reading a demonstration of God's existence in to these lines.
The Third Way: Contingency
The third way is taken from possibility and necessity, and goes like this: we find among things those that have the possibility of existing or not existing, since they are found to be generated, and to corrupt, and consequently have the possibility of existing or not existing. ...Therefore, if at one time nothing was in existence, it would have been impossible for anything to have begun to exist; and thus even now nothing would exist—which is obviously false. Therefore one must posit the existence of something that is the necessity of other things. This is what everyone speaks of as God.
St. Augustine takes up Platonic argument: whatever changes, does not exist of itself but is made by another, and St. John Damascene takes this argument. Besides, the non-Christian authors also developed a proof of the existence of God from the mutability of things. While, people must conclude that Aquinas used the Third Way in a novel and original way to construct an argument which is his own, because St. Thomas followed the Jewish philosopher quite closely and because he has differences come to light and an essential part. .
The Forth Way: Properties
One finds among things that there are some more and some less good, true, noble, and so forth. But "more" and "less" are said of different things insofar as they approach, in their different ways, something that is the maximum, as in the case of a thing being said to be hotter insofar as it most nearly resembles that which is hottest.... Therefore there must also be something that is to all beings the cause of their existence, goodness, and every other perfection; and this we call God.
The ultimate source of the Fourth Way is Plato. There is an outline of the argument in the Symposium, and "St. Thomas also uses the argument in a form which goes back to Proclus." St. Thomas Aquinas acknowledges this attachment of the argument to Plato. Leo explained, "above all Aristotle teaches the unity of being, which to St. Thomas is of paramount importance: the transcendental coalesce in the unity of the concrete thing and do not constitute juxtaposed distinct formal realities." Obviously, however, the argument of St. Thomas fundamentally differs from Plato's view of participation.
The Fifth way: Design
The fifth way is based on the guidedness of nature. Goal-directed behavior is observed in all bodies obeying natural laws, even when they lack awareness. Their behavior hardly ever varies and practically always turns out well, showing that they truly tend to goals and do not merely hit them by accident. But nothing lacking awareness can tend to a goal except it be directed by someone with awareness and understanding; the arrow, for example, requires an archer. Everything in nature, therefore, is directed to its goal by someone with understanding, and this we call God.
The teleological argument, the fifth way, is that proof of God's existence which is most widely found in religious and philosophical tradition. "The reason is that it is obvious to man that order does not come from nothing but requires someone who arranges things." Xenophon, Plato, and Aristotle present the argument in their books, Memorabilia, Timaeus and the Laws, and De philosophia. St. Thomas quotes a text to this effect of St. John Damascenus.
In summary, St. Thomas Aquinas used philosophical idea and terms to proof of existence of God in his book, Summa Theologiae. Finding the ideas of Aristotle, Plato, and Xenophon in the book of Aquinas is not difficult, because Aquinas acknowledged philosophy and philosophical methods to one of gifts given from God. Therefore, St. Thomas Aquinas is a person who tried to use philosophy to understand revelation. To Aquinas, reason and faith are important to recognize God.
However, even though Thomas accepted philosophy, he did not remain the area of philosophy. Thomas developed philosophical thoughts to theological ideas and Christian thoughts. Therefore, St. Thomas Aquinas is n wise person in terms of filling the gap between reason and faith. Thomas uniquely unites the two sides of the debate within the proof, so, in this proof, people find a synthesis of Thomas' philosophy and theology.
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- Atkinson, Melissa S. "Aristotle And Aquinas: Intrinsic Morality Versus God's Morality." Rebirth Of Reason. July 28, 2006. http://www.solohq.org/Articles/atkinson/Aristotle_and_Aquinas_Intrinsic_Morality_versus_Gods_Morality.shtml/ (accessed April 29, 2009).
- Bauerschmidt, Frederick Christian. Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas. Grand Rapids: Brazos Press, 2005.
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- Elders, Leo J. S.V.D. The Philosophical Theology of St. Thomas Aquinas. Leiden: E. J. Brill, 1990.
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- Lee, SooWhan. ??? ????? ??? ??? ??? ??? ??? ?? [The Relation between Theology and Philosophy]. Soowon: Hapshin Theological Seminary Publishing, 2006.
- Martin, Christopher. The Philosophy of Thomas Aquinas: Introductory Readings. Edited by Christopher Martin. London: Routledge, 1998.
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- Miller, ED. L. Classical Statements on Faith and Reason. Edited by ED. L. Miller. New York: Random House, 1937.
- Moreland, J. P.. Kingdom Triangle. Grand Rapids: Zondervan, 2007.
- Nash, Ronald H. Faith & Reason: Searching for Rational Faith. Grand Rapids: Zondervan Publishing House, 1998.
- Vinson, William Edward, Jr. "The Kingdom of God according to Thomas Aquinas : a Study of the relationship between Thomas's philosophy and theology reflected in his doctrine of church and state." PhD diss., Southwestern Baptist Theological Seminary, Fort Worth, TX, 1987.
- Wawrykow, Joseph P. The Westminster Handbook to Thomas Aquinas. The Westminster Handbooks to Christian Theology, ed. Westminster John Knox Press. Louisbille: Westminster John Knox Press, 2005.
- Seonghoon Han, ???? ?? ??? ??? ??? ?? ??? ?? [An Investigation on the Natural Knowledge of God and the Experiential Knowledge of Life] (Deagu: Catholic University Press, 2002), 11.
- J. P. Moreland, Kingdom Triangle (Grand Rapids: Zondervan, 2007), 22.
- Ronald H. Nash, Faith & Reason: Searching for Rational Faith (Grand Rapids: Zondervan Publishing House, 1998), 71.
- C. Stephen Evans, Faith beyond Reason (Grand Rapids: Walliam B. Eerdmans Publishing Company, 1998), 1.
- William Edward Vinson, Jr.,"The Kingdom of God according to Thomas Aquinas : a Study of the relationship between Thomas's philosophy and theology reflected in his doctrine of church and state" (PhD diss., Southwestern Baptist Theological Seminary, Fort Worth, TX, 1987), 1.
- Richard Amesbury, "Fideism," Stanford Encyclopedia Of Philosophy, May 6, 2005, http://plato.stanford.edu/entries/fideism/ (accessed April 20, 2009).
- ED. L. Miller, Classical Statements on Faith and Reason, ed. ED. L. Miller (New York: Random House, 1937), 11.
- SooWhan Lee, ??? ????? ??? ??? ??? ??? ??? ?? [The Relation between Theology and Philosophy] (Soowon: Hapshin Theological Seminary Publishing, 2006), 19.
- Josh, "Faith and Reason (part 2): The Relationship Between Faith And Reason," Quadrivium Team, February 29, 2008, http://quadri.wordpress.com/2008/02/29/faith-and-reason-part-2-the-relationship-between-faith-and-reason// (accessed April 28, 2009).
- Alfred J. Freddoso, "Ockham on Faith And Reason," University Of Notre Dame, September 12, 1998, http://www.nd.edu/~afreddos/papers/f&rcam.htm. (accessed April 28, 2009).
- Evans, Faith beyond Reason, 4.
- Eric G. Jay, The Existence of God: a Commentary on St. Thomas Aquinas's Five way of Demonstrating the Existence of God (London: Society for Promoting Christian Knowledge, 1948), 17.
- Lee, ??? ????? ??? ??? ??? ??? ??? ?? [The Relation between Theology and Philosophy], 36.
- Frederick Christian Bauerschmidt, Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas (Grand Rapids: Brazos Press, 2005), 21.
- Christopher Martin, The Philosophy of Thomas Aquinas: Introductory Readings, ed. Christopher Martin (London: Routledge, 1998), 75.
- Ibid., 21
- Melissa S. Atkinson, "Aristotle and Aquinas: Intrinsic Morality Versus God's Morality," Rebirth Of Reason, July 28, 2006, http://www.solohq.org/Articles/atkinson/Aristotle_and_Aquinas_Intrinsic_Morality_versus_Gods_Morality.shtml/ (accessed April 29, 2009).
- Don McGaughey, "Thomas Aquinas and the problem of faith and reason," Restoration Quarterly 6, no. 2 (1962): 70.
- Lee, ??? ????? ??? ??? ??? ??? ??? ?? [The Relation between Theology and Philosophy], 41.
- Mortimer Jerome Adler, "The last lecture: thinking about God, believing in God," Religion and Intellectual Life 4, no. 1 (fall 1986): 75.
- Bauerschmidt, Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas, 51.
- Leo J. Elders S.V.D, The Philosophical Theology of St. Thomas Aquinas (Leiden: E. J. Brill, 1990), 95.
- Ibid., 96
- Aristotle, The Physics 2, trans. Cornford Philip H. Wicksteed, Francis M (London: William Heinemann LTD, 1989), 197.
- Ibid., 217
- Bauerschmidt, Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas, 53.
- Leo, The Philosophical Theology of St. Thomas Aquinas, 100.
- Seokwhan Han, ??? ????? ??? ??? ?? ?? [On the Proof of God's Existence in Thomas Aquinas] (Ulsan: Ulsan University Press, 2001), 31.
- Bauerschmidt, Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas, 54.
- Leo, The Philosophical Theology of St. Thomas Aquinas, 107.
- Ibid., 109
- Bauerschmidt, Holy Teaching: Introducing the Summa Theologiae of St. Thomas Aquinas, 54.
- Leo, The Philosophical Theology of St. Thomas Aquinas, 117.
- Ibid., 118.
- St. Thomas Aquinas, Summa Theologiae: a Concise Translation, ed. Timothy Mcdermott (Westminster: Christian Classics Inc, 1989), 13.
- Anna Case-Winters, "The Argument from Design: What Is at Stake Theologically?" Zygon 35, no. 1 (March 2000): 70.
- Leo, The Philosophical Theology of St. Thomas Aquinas, 124.