This is what I have learned from buddism. Just my thoughts and perspective. This world is a dream. Only your consciousness exists. Your body, thoughts, consciousness is not you. It appears and disappears. It is always like that. There is Karma but there is no constant self. The self changes. The life cycles you had past life and future life is not the same. It is panca khandha that make you existm it gathers and be gone. Everything doesnt have its substance. All things change... Just scribble of thoughts.