dogmatist

noun

1. A stubborn, assertive, opinionated person.
2. One who derives philosophical or religious principles from a priori assertion or revelation rather than evidence or experience.

   “Dogmatic philosophies have sought for tests for truth which might dispense us from appealing to the future. Some direct mark, by noting which we can be protected immediately and absolutely, now and forever, against all mistake—such has been the darling dream of philosophic dogmatists.”