Four Kinds of Knowledge: Revealed Knowledge, Speculative Knowledge, Scientific Empirical Knowledge, Practical Empirical Knowledge. This book is intended as a discussion of human knowledge and a denial of the 'problem' of human knowledge usually studied under the name of 'epistemology', a branch of philosophy forbidden to those who accept the claim of St. Thomas Aquinas that things are true.
From a philosophical or theological viewpoint, epistemology is a sin of sort, a dangerously corrupting ﬁeld of study. St. Thomas Aquinas never spoke of the so-called problems of knowledge. Etienne Gilson was the most prominent and plausible Thomist of modern times; Gilson denied that his good friend Jacques Maritain was a true Thomist just because Maritain was willing to discuss problems of knowledge with modern philosophers and theologians.