1. Tertullian (2nd century A.D.) - "What indeed has Athens to do with Jerusalem? What concord is there between the Academy and the Church?"

For Terrullian, there was an irreconilable antagonism between Christianity and philosophy. Divine Revelation is all that is needed for the Truth. He rejected philosophy as having any meaning for Christians. It was "foolishness."

2. Saint Augustine (354 - 430) - "Understanding is the reward of faith. Therefore seek not to understand that thou mayest believe, but believe that thou mayest understand."

Augustine argued that unless you believe, you cannot understand. Revealed religion is the basis of rational knowledge. He accepted philosophy, especially Platonism, to produce a rational understanding of the truth from faith.

3. Saint Anselm (1033 - 1109) - "Faith seeking to understand."

He applied dialectic and logic to revelation. He tried to show that there was a necesary, logical connection between Christian principles. Revelation must be demonstrated in terms of logical demonstrations.

4. Saint Thomas Aquinas (1225 - 1274) - "Faith supplements Reason."

Knowledge is attained by reason and faith. Some truths, including religious truths, can be discovered by the use of reason or other philosophy. But other truths, especially religious truths, including the Trinity, can only be attained by faith. Philosophy cannot discover these truths. Reason cannot prove them to be true or false. For Aquinas, the truths of philosophy would never conflict with the truths discovered by faith. Reason and Revelation are in harmony, not conflict.

He also believed that Human Reason and Will could cooperate with Divine Grace. Human reason and will can enable man to do some good works and discover some of the truths of Christianity, but only when God gives you grace can you be saved. Only when Reason is supplemented by Revelation can one know the truths of Christianity.