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#1. I disagree with Epictetus' view that we cannot control the world but instead we should control our minds. I feel we can influence, for example, we can influence other people's opinions of us. In honesty, I am inclined to agree. I think we do have causal power in the world. However, we can still find something true in Epictetus, which is that we can and should control our reactions to things that we cannot control.
#2. How much is virtue related to happiness? The answer to this depends on whether we take happiness to mean pleasure or living well. Aristotle thinks that happiness, which is better thought of as living well, consists in being virtuous. To be virtuous is to be happy. Now, a hedonist would say that one need not be virtuous to be happy. A hedonist would say that to be good is to perform actions that maximize pleasure. A satisfaction desire theorist would say that being virtuous is related to happiness insofar as a person who wants to be virtuous is able to achieve that goal. If a person does not want to be virtuous, then he or she can be happy without virtue.
#3. In the case of slavery or oppressive regimes, would it be right to accept yourself as a slave as part of the divine order of things in order to be happy? Or would Epictetus say that slavery is against the divine order of things and so happiness is not possible. Unfortuntately, Epictetus lived in a world with slavery, so he would say that being a slave is a natural part of the world. Yes, even slaves must accept their place in the world and find tranquility, even-mindedness and freedom in spite of it. Perhaps this conclusion is a reason to reject or modify Epictetus' view.
#4. If you compare yourself to people having it a lot worse than you, would you consider yourself fortunate or lucky, would you consider those people unfortunate, unlucky or both? I take it that we are talking not about a specific theorist but only in general terms. In which case, it seems that all of these labels can be applied in a meaningful way by different people depending on their inclinations to find events lucky or unlucky.
#5. Is Epictetus a religious person? Does he believe in the afterlife? Epictetus believed in the gods, so he was a religious person. However, he did not believe that there was life after death.