Many people don't recognize the impact of the spirit realm. All people have a spirit sent from God that gives life at conception. Because of the sin nature, that spirit is dead. Not dead in the sense that it doesn't have the ability to keep our heart beating, but dead in the sense that we are separated from God because of sin. When Paul was in Athens, he was talking to unbelievers when he said that God gives us life and breath and the ability to have our being.
...for in Him we live and move and exist, as even some of your own poets have said, ‘For we also are His children.’ - Acts 17:28