Things do not fall down, but are attracted to the center of planet Earth, this being a model that can be complicated including other celestial bodies. The difference is not important at the local level, but it is fundamental to understand it if our plan includes escaping from the planet. In the same way, knowing what sentience really is (Open Individualism, Empty Individualism) does not seem very important if this in practice manifests itself in other ways (Closed Individualism), but in a project that pretends to escape from all suffering it is absolutely essential. Of course, this may sound as far-fetched and ambitious as escaping the gravity of planet Earth. A few centuries ago no one in his right mind would have proposed something like that, or if he had, he would have been ridiculed as a pretentious madman.
Models of Identity
Models of identity tries to answer the question: Who feels?
…it is common to access some memory of adolescence and to be ashamed of oneself, of what we did or even of what we thought at that moment. It seems as if someone else has done it. It can become humiliating or almost inconceivable that we would have been able to think or do such a thing. But this is explained simply if we accept that we are precisely talking about another person: my “I of the past”. Every millisecond (or minimum unit of time) we are a different person. This is called Empty Individualism.