His initial statement, "It takes seven years for each and every atom in your body to be replaced by another." sounds like an urban myth, and he provides zero documentation for it.
I am well aware of that, but simply claiming it's an urban myth is not the same as proving it's wrong. I have provided the links I could find, take that for what you want.
It doesn't take a hundred or even 50 years why do you think the body fall apart over time. If the body was static we wouldn't die let a lone grow up to die.
It is a fact that the human body is in flux and not stable it is also a fact that your cells most of them die out pretty fast which is why we have to eat and drink. And that is what matters. The you today isn't the same you as 7 years ago.
The cells in the body do turn over, but not uniformly every 7 years. Some things are as old as you are. The atoms in your skeleton get replaced every 7 tears, but these aren't the most permanent things in your body.
Supposedly the ancient Romans believed that one's body and soul renewed itself every seven years, which is probably the origin of this myth.
Regrettably, I can't find a good citation on that, although it's widely cited as the origin for the superstition that breaking a mirror causes seven years of bad luck.
As a complete aside, I can explain the 7 years of bad luck.
Back in the 1500's and up, when mirrors were smoothed silver on glass, they were only for royalty. And as per royalty, there were servants. The "bad luck" was actually punishment of 7 years of indentured servitude to pay for a broken mirror.
Suppose that, in an instant, your body and mind ceased to exist. Just completely vanished.
And suppose further, that nobody witnessed this, and that one instant later, by some very unlikely process, some matter or energy spontaneously organized itself into an exact duplicate of you, down to every last quantum wobble, in exactly the same place that you were standing.
Would either this new you or the old you notice? Would "you" still be "you"?
What if instead of miraculously vanishing, you were instead vaporized by your neighbor, using a ray that recorded the position or every atom? It's murder, right?
What if he recombines you, just like in your example an instant later. Is it murder?
A minute later. Murder?
An hour, day, week, month, year. Murder?
What if he just promises to everyone to put you back together. Later. In the future. Murder?
What if his name is Scotty, and rather than zapping you, he merely stored you in his transporter buffer and delayed beaming you to your destination for a moment?
What if he didn't delay at all? Did he kill you just by letting your atoms get ripped apart and reassembled elsewhere?
Don't these questions hint at "death" being a leaky abstraction?
It seems that people have their own definition of death with details added to the general concept. Then, when exposed to these hypothetical scenarios, they either say "it is murder" or "it isn't murder", depending on what their personal definition of "death" is.
The problem is that if we redefine death as "no chance of ever coming back", some people would still not be ok with being temporarily disintegrated because they believe it would be someone else who would come back.
So the concept of death should actually be split in two: death as in "I believe it would not be me anymore", and death as in "the functional unit defined as you would not be operational anymore".
