Ancient Greek stoic philosopher of Greek heritage. His entire theory of philosophy was geared towards answering one question: how to live. He believed that human happiness didn’t depend on things themselves, but how we see them; that alone brings us happiness or consumes us with suffering. Hence the main objective of philosophy and any subsequent ethics was finding a way to distinguish the things beyond our control and not worth worrying about from the things that are in our power to change. This idea is the basis of contemporary psychological therapy.