Outer Limits of Reason by Noson S. Yanofsky Page A

hundreds of questions can be posed about change in a person’s thoughts, memories, and desires. Again, philosophers and science fiction writers have become quite adept at describing interesting scenarios that challenge our notion of a human being as a continuous stream of mental states. These scenarios are concerned with Alzheimer’s disease, amnesia, personality changes, split-brain experiments, multiple personality disorders, computers as minds, and so on. There are also many questions along the lines of the mind-body problem. How much is the mind—that characterizes a human being—independent of the brain, which is a part of the body?
    One of the more interesting challenges to the position that continuity of mental states characterizes a human being is the question of transitivity of identity . My mental states are essentially the same as they were ten years ago. That means I am the same person I was ten years ago. Furthermore, ten years ago, my mental states were essentially the same as they were ten years earlier. Hence the person I was ten years ago is the same as the person I was twenty years ago. However, at present, I do not have similar mental states to those I had twenty years ago. So how can it be that I am the same person I was ten years ago, and that person is the same as I was twenty years ago, but I am not the same as I was twenty years ago?
    Yet another option is that everyone has a unique soul that determines who they are. Avoiding the questions of the definition or existence of a soul, let us concentrate instead on how this answers our question of the essential nature of a human being. Assuming the existence of a soul, what is the relationship between the soul and the body? What is the relationship between a soul and a person’s actions, psyche, and personality? If there is no connection, then in what sense is one soul different from another soul? How can you differentiate between souls if they have no influence over any part of you? What would the purpose of a soul be? If, on the other hand, a connection exists, then does the soul change when the body, actions, psyche, or personality changes? Is the soul in flux? If the soul does change, we are back to the same questions we had previously asked: Who is the real you? Are you the one with the soul prior to the change or are you the one with the changed soul?
    Most people probably have an opinion representing some hybrid version of all three ideologies: a person is a composite of body, mind, and soul. Nevertheless, all schools of thought are somewhat problematic.
    Rather than answering all the questions posed in this section, let us try to resolve the issues by meditating on why none of the questions have clearcut answers. Why is it that when we pose these questions to different people, we get so many different answers?
    Examine the way people learn to recognize different objects, make definitions, and create distinctions. In the beginning, babies are bombarded with many different sensations and stimuli. As toddlers grow, they learn to recognize objects in the world. For example, when they see a shiny silver thing covered with brown gooey stuff coming toward them, they have to learn that it is applesauce on a spoon and that they should open their mouth. By learning to recognize that the physical stimulus of silver covered with brown gooey stuff is applesauce, they are able to handle life better. Human beings need to classify objects. We learn how to tell things apart and determine when they are the same. We learn that an object still exists even when it is out of sight (“object permanence”). Children learn after a while to recognize their mother. A few months later, they learn that even though she is wearing makeup—that is, even when she looks different—she is still the same person. Children have to learn that their mother is the same even when she is wearing perfume and smells totally different. Here toddlers are acting