I am reading Neitzsch's "Human, All Too Human", in one of his aphorisms he states that logic is optimistic. Does he mean that it would be foolishly optimistic to trust logic or in its truth? Or does he mean something else I just can't seem to understand?

Thank you for your question. I'm guessing you are referring to aphorism 6 in the first volume. You are certainly right to call Nietzsche up here -- the reference to the concept of optimism is not at all clear. In fact, it goes back to an earlier book of Nietzsche's, The Birth of Tragedy . (If you want to look, the clearest -- which isn't saying much in this case -- treatment of this idea is found in chapter 18.) There Nietzsche argues that an important change took place around the time of Socrates, and that what we now think of as science, broadly speaking, was 'invented'. What characterises this Socratic science? Well, logic, first of all, broadly understood in its Greek sense as a rational enquiry into the nature of things. But also, Nietzsche says, a certain optimism. Science only makes sense if the world CAN be understood and that, once it is understood, it can be CHANGED for the better. Science, he says, is intrinsically optimistic about its own utility. Now, here in Human, All Too...

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?

That's a very interesting question,thanks for asking. There seems to be a difference between your twoexamples that is worth thinking about. The first example clearly anddirectly involves a moral choice. There we have a person who lives acontradiction in that they believe that X is wrong in a specificallymoral sense of 'wrong', and yet are complicit in X. In the secondexample, though, there doesn't appear to be anything moral at stake(there may in fact be, but for the sake of argument here let usassume that there is not). So, we have a person who thinks that X iswrong in the sense of false, but still behaves as if X. If there is a duty to removecontradictions in our beliefs and behaviours, it seems more urgent inthe first case. The contradiction there involves some moral wrong, orsome failure in the consistency of moral character. Consistency is afeature valued in most moral systems. See this question and answer: http://www.askphilosophers.org/question/715 In the second case, there may beself...