After Nicaea: Can the historian's pickaxe build a cathedral?

This essay asks whether a post-Nicene Christian reformation is possible: not another argument that the Trinity is late or philosophically costly, but a movement that could accept historical criticism without exemptions, confess the Father alone as God, hold a positive doctrine of Jesus, resurrection and revelation, sustain demanding religious practice, and build an institution that survives its founder, while applying the same critical standards to the Qur’an and hadith that it applies to the New Testament. My argument is that the components already exist and have never been assembled. The non-trinitarian churches that succeeded did so by raising religious certainty, not lowering it. The unitarian networks closest to the intellectual project remain institutionally thin. And academic criticism, whatever its power to dismantle, produces no liturgy and no second generation. The essay engages Harnack and Ratzinger’s reply at Regensburg, the early high Christology of Hurtado and Bauckham, the sociology of strict churches, the knot binding resurrection to revelation, Islam as both proof of possibility and chief competitor, and the likely religious consequences of artificial intelligence. It closes with a registered wager: probabilities of 55, 15 and 65 per cent, each with operational definitions strict enough to fail, fixed review dates in 2040, 2055 and 2075, and update rules written in advance so that no outcome can be reinterpreted after the fact. Forecast recorded 19 July 2026. Arabic original: doi.org/10.5281/zenodo.21444702 . - Keywords and subjects: Nicaea · Trinity · Unitarian Christianity · historical Jesus · Christianity · historical criticism · forecasting · religious demography · sociology of religion