Cal Dave,
Well, when we say something is a live we do not mean that life is a live but rather the thing that is moving or "has" life. We say, such and such a thing has life... so the "thing" that "has" this something called life is not the same as life itself.
Life is invisible but admitted to act upon animals, humans, plants etc. So the question comes... if life is admitted but invisible of itself, what is it then if not matter? And if it's not matter, how can it affect matter? And if life isn't matter, than it cannot be destroyed... it is eternal. When man understand the Truth of who he really is, he realizes that his life is not in his body, but rather his body is in life.
The body being only an idea made of matter which can be changed, the eternal element that changes mind and body and recognizes the change is who man really is.
If you'd like to understand this more scientifically, I will be happy to get into more details.