Educação Superior::Ciências Humanas::FilosofiaPresents a class of Professor Shelly Kagan that speaks about the question of the metaphysical key to personal identity. What does it mean for a person that presently exists to be the very same person in the future? The first approach to answering this question is the "soul theory," that is, the key to being the same person is having the same soul. Difficulties with that approach are then discussed, independent of the question whether souls exist or not