This dissertation consists of three freestanding essays. The first, Rethinking the Imposter Phenomenon, argues for the rationality of certain “Imposter” beliefs that are usually thought to be irrational. The second, On the Practical Insignificance of ‘Ought Implies Can’, argues that we’re often not in a position to rule out moral requirements on the basis of the principle ‘Ought Implies Can’ because it is usually very hard to acquire the justified belief that we cannot fulfill some candidate obligation. The third, Authenticity, Imagination, and Transformative Choice, argues that we can sometimes authentically choose to do something that we’ve never done before because we can sometimes adequately imagine what that thing is like.