We exists with the 'live' Qi (spirit) moving in our bodies.
Once we die, our live Qi will be moving out of our bodies and go through a cycle for the next rebirth.
Unless we understand our purpose in life, we will be reborn again and it starts all over again. Some people may have experiences in Soul Travel or Astral Travel. They have the experience of knowing that spirit (soul) exists. They can travel and see the world during the period where our bodies are in the deep sleep stage.
Once you have achieved in Soul Travel, you will soon realise that we are just in a form of live Qi.