necessitarian

Of or pertaining to necessity or to necessitarianism: opposed to libertarian.

One who maintains the doctrine of philosophical necessity, in opposition to that of the freedom of the will: opposed to libertarian.

Of or pertaining to the doctrine of philosophical necessity in regard to the origin and existence of things, especially as applied to the actings or choices of the will; — opposed to libertarian.

One who holds to the doctrine of necessitarianism.

necessarian

One who maintains the doctrine of philosophical necessity, in opposition to that of freedom of the will: opposed to libertarian. (The Century Dictionary, The Century Co., New York, 1911).

Of or pertaining to necessity or necessitarianism: opposed to libertarian.   The Arminian has entangled the Calvinist, the Calvinist has entangled the Arminian, in a labyrinth of contradictions. The advocate of free-will appeals to conscience and instinct — to an a priori sense of what ought in equity to be. The necessitarian falls back upon the experienced reality of facts. Froude, Calvinism. (The Century Dictionary, The Century Co., New York, 1911).

someone who does not believe the doctrine of free will