/summa/FP/FPIII/FP_Q32:
We proceed to inquire concerning the knowledge of the divine persons; and this involves four points of inquiry:
(1) Whether the divine persons can be known by natural reason?
(2) Whether notions are to be attributed to the divine persons?
(3) The number of the notions?
(4) Whether we may lawfully have various contrary opinions of these notions?