Trinity doctrine was argued through supposedly rational criteria rooted in Latin influence

Evidence

Petrus equates substance with the Father, wisdom with the Son, and will with the Holy Spirit; the rationalistic explanation of the Creation, for Alfonsi, requires the existence of the Trinity. Tathlîth al-wahdânîyah gives essentially the same argument, though its triad differs slightly: it is power, knowledge, and will. Both authors are working within a well-established tradition of Arab Christian apologetics; both emphasize supposedly rational and scientific proofs. Reason (ratio) can disprove Judaism and Islam and prove the essence of Christian truth. — John V. Tolan, Saracens, 829

Categorization

• XREF: Refines the vault’s broad claim that theological polemics against Islam rested on theology, not pure reason — medieval Arab-Christian apologists insisted their proofs were rational.