3. How is it possible to know God with only the light of human reason?
Starting from creation, that is from the world and from the human person, through reason alone one can know God with certainty as the origin and end of the universe, as the highest good and as infinite truth and beauty.
Although a person can know this with certainty, they may not in fact do so and there are even religions that do not understand the word ‘God’ in this way. Difficult to know what to make of that, seems atheistic to me in spite of the religiousity.