Reason can defend but not prove the Christian faith.

Evidence

Thomas is clear about the limits of the defensive arguments he provides: … First of all I wish to warn you that in the disputations with unbelievers about articles of the faith, you should not try to prove the Faith by necessary reasons. This would belittle the sublimity of the Faith, whose truth exceeds not only human minds but also those of angels; we believe in them only because they are revealed by God. … Yet whatever comes from the Supreme Truth cannot be false, and what is not false cannot be repudiated by any necessary reason. Just as our Faith cannot be proved by necessary reasons, because it exceeds the human mind, so because of its truth it cannot be refuted by any necessary reason. So any Christian disputing about the articles of the Faith should not try to prove the Faith, but defend the Faith. Thus blessed Peter [1 Pet. 3:15] did not say “Always have your proof,” but “your answer ready,” so that reason can show that what the Catholic Faith holds is not false. — John V. Tolan, Saracens, 1229 (#corroborates, via linked claim)

Alfonso Buenhombre’s hoax epitomizes the failure of the Dominican ambition to convert the Jewish and Muslim worlds to Christianity through disputation. Late thirteenthand fourteenth-century theologians increasingly denied that it was possible to prove the faith through reasoned argument: reason can be used to defend the faith, for Thomas Aquinas, but not to prove it. Both the Franciscan and Dominican approaches turned out to be failures. One of their sharpest critics, Ramon Llull, forged his own idiosyncratic strategy for converting Muslims. — John V. Tolan, Saracens, 1277 (#corroborates, via linked claim)

Alan, for example, assuming that Muslims defend polygamous marriage on Old Testament grounds (the example set by the Patriarchs), iv.vii. Alexander: in Petrus. Bles., MPL 207 and Paris, yr. 1169 (personal insertion in the old chronicle). Guido: 15, citing Isa. Lxvi1.5. (Parallel to the assumption by Christian polemists that Muslims will accept the text of the canonical Old Testament, is that Jews will accept the (Catholic) deuterocanonical or (Protestant) apocryphal books of the Old Testament. This happens even in the Rabbi Samuel correspondence. — Norman Daniel, Islam and the West, 1970 (#complicates, via linked claim)

Categorization

• XREF: connects to: Even Lull doubted laypeople could grasp his Trinitarian proofs; Medieval doctrine held reason could attack rivals but never prove Christian truth.; Medieval Dominicans held reason could defend but never prove the faith (+11 more)

Broader Connections

• Late medieval theologians concluded reason could defend but never prove the Christian faith. #corroborates (1.00) — John V. Tolan, Saracens, 1277
• Thomas Aquinas held that reason can defend faith but never prove it #corroborates (1.00) — John V. Tolan, Saracens, 1229
• Arguing against other faiths is impossible without accepting that faith’s authority premises #complicates (0.90) — Norman Daniel, Islam and the West, 1970
• Reason’s defense of law rests on its open discussability, not its content #complicates (0.75) — R. W. Southern, Western Views of Islam in the Middle…, 558
• Medieval theologians deployed reason only to attack rivals, not to prove their own faith #complicates (0.75) — John V. Tolan, Saracens, 1220