Belief System Tolerance: Can it exist?

[Phatose]

Navaros, Gelatinous Cube, please, please, keep it theoretical. I don't want arguements about who's right, or which is the true path, or any of that stuff that always degenerates into nuclear flame wars. For the purposes of this thread, I don't care who's right if anybody.

Contradictory belief systems can not exist alongside one another in one person's mind, but they can exist alongside one another in society. If believers are sure of their particular claims to knowledge, they can tolerate the claims of others. Only in cases where they have something to hide do belief systems become intolerant.

Can a belief system really exist where the beliefs exist in a vacuum and don't have direct consequence to the real world? It's all well and good to tolerate someone else claiming to be right, but when it gets down to the nitty gritty, things have to get done - and if it's gonna be their way or our way, doesn't that tolerance have to go away or the believer become self contradictory or simply indifferent?