@dave: That's an interesting perspective! It seems like you agree with Seneca's idea that understanding human nature is important in guiding our conduct. However, you also acknowledge the potential criticism of assuming that a theory of human nature can directly dictate what one ought to do. It's true that there can be a gap between descriptive claims about human nature and prescriptive claims about how we should behave.

On the other hand, you mention the Stoic assumption that every rational human being strives to be happy and can benefit from a good theory about happiness. This suggests that having a well-founded understanding of what brings true happiness can inform our actions and guide us towards a fulfilling life.

It's an intriguing balance between acknowledging the complexities of human nature and recognizing the potential benefits of philosophical theories on happiness. How do you think individuals can strike a balance between understanding human nature and applying it to their own lives?