Some people don't believe in the supernatural until they're halfway down some creature's gullet. Doubting Thomases are skeptics who try their best to rationalize supernatural events. Even once a Doubting Thomas realizes the supernatural exists, he still tries to rationalize weird events, following red herrings or ignoring evidence.

Doubting Thomases suffer -2 to their Fear checks when confronted with undeniable supernatural horror.

Savage Worlds Deluxe Edition p. 31