Some believe faith leads to reason, others that reason leads to faith, others that faith is reasonable, others that faith is entirely unreasonable, but do it anyway. I have chosen to only explore ideas within the Western conversation, since that is the general purpose of this small paper.
Aristotle and Plato (400bce): Both thinkers developed versions of natural theology by showing how religious beliefs emerge from rational reflections on concrete reality as such. An early form of religious apologetics – demonstrating the existence of the gods — can be found in Plato’s Laws. Aristotle’s Physics gave arguments demonstrating the existence of an unmoved mover as a timeless self-thinker from the evidence of motion in the world. https://www.iep.utm.edu/faith-re/
St. Paul (first century ce): appeals for a new examination of divinity not from the standpoint of creation, but from practical engagement with the world. Paul argues that in fact anyone can attain to the truth of God’s existence merely from using his or her reason to reflect on the natural world. https://www.iep.utm.edu/faith-re/
St. Augustine (late fourth century ce): He felt that intellectual inquiry into the faith was to be understood as faith seeking understanding (fides quaerens intellectum). To believe is “to think with assent” (credere est assensione cogitare). It is an act of the intellect determined not by the reason, but by the will. Faith involves a commitment “to believe in a God,” “to believe God,” and “to believe in God.” https://www.iep.utm.edu/faith-re/
St. Thomas Aquinas (13thcentury): Aquinas sees reason and faith as two ways of knowing. ‘Reason’ covers what we can know by experience and logic alone. From reason, we can know that there is a God and that there is only one God; these truths about God are accessible to anyone by experience and logic alone, apart from any special revelation from God. ‘Faith’ covers what we can know by God’s special revelation to us. These truths about God cannot be known by reason alone. Faith builds on reason. If we understand faith and reason correctly, there will be no conflict between what faith tells us and what reason tells us. http://www.harryhiker.com/re/r-a4–00.htm
Rene Descartes (17thcentury): On the night of 10–11 November 1619 (23 yrs old), Descartes shut himself in a room with an “oven” to escape the cold. While within, he had three dreams and believed that a divine spirit revealed to him a new philosophy. Descartes constructs a theory of the universe that begins with doubt rather than faith. In mistrusting his senses, because he well knows that the senses can sometimes deceive, Descartes leans towards the mind and the intellect as reliable sources of information. Descartes wants to prove that God exists in order to found metaphysically the ‘new science’ which Galileo’s mathematical and experimental work had begun to articulate. For Descates,God becomes explicated by means of the foundation of subjective self-certainty. His proofs hinged upon his conviction that God cannot be a deceiver. Little room is left for faith.https://www.faith.org.uk/article/november-december-2012-descartes-as-synthesiser-of-christianity-and-science https://www.iep.utm.edu/faith-re/
Baruch Spinoza (mid 17thcentury): His extremely naturalistic views on God, the world, the human being and knowledge serve to ground a moral philosophy centered on the control of the passions leading to virtue and happiness.
Proposition 11: God, or a substance consisting of infinite attributes, each of which expresses eternal and infinite essence, necessarily exists.. If you deny this, conceive, if you can, that God does not exist. Therefore, by axiom 7, ‘If a thing can be conceived as not existing, its essence does not involve existence’, his essence does not involve existence. But this is absurd. Therefore, God necessarily exists, q.e.d.”
His definition of God is meant to preclude any anthropomorphizing of the divine being. He writes against “those who feign a God, like man, consisting of a body and a mind, and subject to passions. But how far they wander from the true knowledge of God, is sufficiently established by what has already been demonstrated.” https://plato.stanford.edu/entries/spinoza/#GodNatu
Immanuel Kant (mid 18thcentury):Kantsays that ‘from the practical point of view, it is one and the same thing whether one founds the divinity of the command in human reason, or founds it in such a person as God, since the difference is more one of phraseology than a doctrine which amplifies knowledge’ and ‘Our previous analysis of object-based formulation of what could be said with no reference to God (or any other object); hence to say that one trusts that God exists is only another, more colourful and possibly more attractive, way of saying that one trusts that things will work out’. https://ethicalrealism.wordpress.com/2010/01/28/kants-argument-for-faith-in-god/
Søren Kierkegaard (mid 19thcentury): Kierkegaard says that there is no bridge between historical, finite knowledge and God’s existence and nature. This gap can only be crossed by a ‘leap.’ Faith is a completely irrational experience, and yet it is, paradoxically, the highest duty of a believer. It is not a spontaneous belief, nevertheless faith is something blind, immediate, and decisive. It has the character of an “act of resignation.” It is unmediated and a-intellectual. https://en.wikipedia.org/wiki/Leap_of_faith
Martin Heidegger(early 20thcentury): Heidegger’s phenomenology of religious life offers faith as lived experience and recognition of ‘the messsiah’. This requires phenomenological clarification and not philosophy of religion. One has to be careful not to speak scientifically when the subject matter is religious experience. If one recognizes a legitimate use of the concept ‘aesthēsis’, perception, in relation to the subject matter of science, then one cannot merely assume the concept has the same legitimacy in speaking of religious experience. https://onlinelibrary.wiley.com/doi/full/10.1111/moth.12447