To regard one's immortality as an exchange of matter is as strange as predicting the future of a violin case once the expensive violin it held has broken and lost its worth.
The hour when you say, "What does my happiness matter? It is poverty and filth, and a wretched complacency. Yet my happiness should justify existence itself!
The question of the origin of the matter in the universe is no longer thought to be beyond the range of science - everything can be created from nothing. It is fair to say that the universe is the ultimate free lunch.
If your mother tells you to do a thing, it is wrong to reply that you won't. It is better and more becoming to intimate that you will do as she bids you, and then afterwards act quietly in the matter according to the dictates of your better judgment.
Now, nothing should be able to harm a man except himself. Nothing should be able to rob a man at all. What a man really has, is what is in him. What is outside of him should be a matter of no importance.