Humankind are unique in the animal world due to their soul having a spirit. It is because their spirits were alive that they could comprehend good and evil, but in learning of it the way they did, they rebeled against God's authority and the Life in their spirits left and in that day they died. This lead to their being cut off from the fruit of the Tree of Life which caused their physical life to begin decaying, but they did not die physically for quite sometime after their fall from Grace.
When God created Adam and breathed into him a living soul, Adam had an alive spirit animating his soul. When the first couple sinned, they lost that characteristic of 'alive souls' via God breathed life in their spirit, so they passed to all their descendants a spirit without God-life in it, thus all descendants of Adam have a lifeless spirit ... where Life is defined as God-life in the spirit. That Life can be restored because of The Grace of God in Christ Jesus.
Jesus taught us about this state of existence with the scene of the rich young ruler who pleaded that he had to go bury his father before he could follow Jesus (let the dead go bury the dead). But that is yet another issue over which our Catholic brethren will likley berate me, so I'll bow out of this thread at this point.
Vaya con Dios, my friend.