casuist

noun3

1. •
   A person who resolves cases of conscience or moral duty.
2. •
   One who is skilled in, or given to, casuistry.

   • The judgment of any casuist or learned divine concerning the state of a man's soul, is not sufficient to give him confidence. — 1692
3. •
   Someone who attempts to specify exact and precise rules for the direction of every circumstance of behaviour.