Before and after the rise of Christianity, philosophers depended largely on developing axioms and using them to draw conclusions about the world. Before Christianity, axioms were generally based on what was obvious to human reason. After Christianity spread, thinkers faced a new source of knowledge, based on faith rather than what seemed obvious to the human mind. Early Christians justified their dependence on faith in different ways. Some have embraced fideism and favored faith even without reason or beyond reason. Others stepped up and merged their new traditions with older ones. Thomas Aquinas describes and responds to several challenges to Christianity. Thomas Aquinas asserts that the study of God as revealed in Christianity, which he calls Sacred Doctrine, is a science that begins with divine revelations as axioms and uses human reason to construct a body of meaningful information about who God is and how humans should behave. He then responds that, if philosophy based on Christianity is a science, it is a lesser science because it is less sure of its conclusions, having accepted them with faith. Thomas Aquinas responds to this argument in two parts. First, he argues that God's revelation is more certain than what seems obvious to humans because God, unlike humans, is omniscient. The only reason it seems less certain is that fully understanding God's level of certainty is beyond human capabilities. Aquinas' second answer is that the Sacred Doctrine deals with more important subjects than the other sciences and is therefore more important. All other sciences, he asserts, indirectly seek the same objective, eternal beatitude, which sacred doctrine directly seeks. It's worthless......middle of paper......assuming that because he experienced the idea of ​​perfection that God must exist. Nevertheless, Descartes was able to provide proof, if not proof, that God exists and is responsible for the clear and correct aspects of human reasoning. The rise of Christianity raised questions about how this new way of thinking, based on faith, could adapt and interact with a world that did not base its thinking on faith but rather on human reason. While some rejected the idea that new and old ways of thinking were compatible, others sought and found ways to reconcile the two ways of exploring the world. The traditional philosophical method of starting from hypotheses that cannot be proven but are assumed to be true and progressing to conclusions based on these hypotheses was applied by Thomas Aquinas and Descartes to meet the mutual challenge posed by Christianity and philosophy..