I really dislike the English translation of this one. It should be unfaithful Thomas, not doubting Thomas. ??????? means not having faith the ?- is equivalent to the english un- or non-, and ?????? means faith, or faithful. Because of sinful human nature, doubt will occur even in the strongest of believers, but unbelief is a conscious decision to not believe. e.g. When Thomas said, "I won't believe until I see and touch."