The topics here are of vital interest to the Christian philosopher and theologian. Question 1 treats of the possibility of our knowing God, and the human limitations of this knowledge. Question 2 concerns theology as a science which reaches out to God by faith in his revealed word and uses philosophical reasoning to throw light on the contents of revelation. In Question 3 Aquinas takes up the nature of faith, showing its relation to religion and its necessity for the welfare of the human race. He argues for the catholicity or universality of the Christian faith and defends the orthodox teaching of the Trinity of Persons in the one God. Question 4 turns to a set of philosophical problems occasioned by Boethius' treatise on the Trinity: the factors that cause a plurality in general, specials and individuals. In this connection Aquinas makes one of his most controversial statements of the principle of individuation.