Do we have a duty to resolve contradictions within our own thoughts and opinions? For example, does a person who thinks killing animals is very wrong, but who has no qualms eating meat, need to revise one opinion or the other? What about someone who doesn't really believe in a god, yet insists on worshipping one and arguing for its existence? Or is it our choice to live with contradictions as we choose?

I would like to add a couple of further considerations to Douglas Burnham's response. I there is too much inconsistency between what a person professes to believe and what that person does, we have reason to doubt that she really believes what she says she does. If a friend claims to believe that killing animals is seriously wrong, yet continues to eat meat with no qualms whatsoever, I will doubt the sincerity of her belief; I will suspect that her professed 'belief' is merely a popular thing to say in certain contexts, or that it is merely an expression of the repulsion that she feels when she imagines certain scenes. Likewise, if a person professes to be an atheist but regularly and earnestly worships god, I will doubt his claim to be an atheist. If there is too much inconsistency between your beliefs one day and your beliefs the next, or your beliefs in one context and your beliefs in another, people will have a hard time relating to you as a single person and you will have a hard time...