OK so we've all heard of this from Carl Sagan, Lawrence Krauss and others and we know the argumentation, I don't refute that. There are other examples, for instance I once calculated (this was before I had taken any QM-course) that since there are more particles in a glass of water than there are glasses of water in the world, eventually, (given enough time, could be millions of years?) you will have a particle (atom/molecule) from each individual every lived on Earth (since we all drink water etc.)
But like I said this was before I had heard of indistinguishable particles etc. So later on, I wasn't so sure if I wanted to tell everyone I met about this amazing revelation, because quantum mechanically, every proton (say) is indistinguishable from every other proton, so this whole story breaks down right?
Similarly with the "we're all star dust"-thing. Is it not wrong to state that the protons in my right hand might come from this, and my left from that?
Or, am I overcomplicating things?
To make things clear:
My question is; if it is right to say that "This atom is from that supernova and that atom is from the other etc." At what level is it right to speak of distinguishable particles. For instance, I breath in, breath out...then someone else in the same room takes a breath, swallowing my atoms/particles. Is it right to say that we've shared the same atoms/protons?