CAE_Jones answered the first part of your question. As for the second part, the human-style half-assed implementation of it is the best we can do in many circumstances, because bringing to bear the full machinery of mathematical logic would be prohibitively difficult for many things. However, just because it's hard to talk about things in fully logical terms, doesn't mean we should just throw up our hands and just pick random viewpoints. We can take steps to improve our reasoning, even with our mushy illogical biological brains.