How does the self, what we call “me,” exist and what establishes its existence? These are crucial questions Buddhism asks. When we are unaware of how we and everyone else exist, either by not knowing or incorrectly knowing how, we experience all sorts of disturbing emotions and attitudes based on this ignorance. Motivated by these disturbing emotions, we act in destructive ways. The compelling urges of our mind and the compulsive impulses of our body and speech drive us to commit such behavior and are what karma refers to. The self is both the agent of these compulsive actions and the experiencer of their results. While all four schools assert in common that we lack a coarse, impossible self or soul – the “atman” asserted by the various non-Buddhist Indian tenet systems – they ascribe to the conventionally existent self different characteristics having different levels of subtlety. Each system refutes the characteristics asserted by the systems less sophisticated than they are, with Prasangika providing the deepest understanding of them all.