Intelligent people maintain multiple sets of contradictory beliefs simultaneously.
No, insane people do that. Orwell even coined a term for it:
Doublethink.
This is the same Orwell who wrote the quote in my signature line you know. He was an intelligent person. He understood subtlety and was not a fundamentalist.
i.e. He himself participated in doublethink and he would not have been ashamed to admit it.