Jean-Pierre Torrell, Saint Thomas Aquinas: The Person And His Work, CUA press, 2005, p. 3. Google Book
Some would not describe Thomas as a philosopher. See, e.g., Mark D. Jordan, "Philosophy in a Summa of Theology", in Rewritten Theology: Aquinas after his Readers (Oxford: Blackwell, 2006) pp. 154–70. [1]
Benedict XV Encyclical Fausto appetente die 29 June 1921, AAS 13 (1921), 332; Pius XI Encyclical Studiorum Ducem §11, 29 June 1923, AAS 15 (1923), cf. AAS 17 (1925) 574; Paul VI, 7 March 1964 AAS 56 (1964), 302 (Bouscaren, vol. VI, pp. 786–88).
