Is this really true?

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Atoms that comprise your body are not atoms that you "carry around" with you throughout your life. Instead, the atoms are constantly being replaced by other atoms, and so the implications of this, is that if you go back say 10 years ago and recall a certain place where you were, the reality is that you really were NOT there, because every atom in your body has been replaced with something new?
 

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  • #2
Defennder
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This really isn't a physics question, but I'll just put it this way, the person I am in 2007 is clearly different from me in 1997, even if every single atom of my body was preserved as it is. I in 2007 have memories of my life in 1997, but who is to say that memories can't be faked or invented? What is the "I" you are talking about anyway?

These type of answers show how fruitless and pointless it is to engage in this type of philosophical discussions. They never seem to lead anywhere, despite the fact they have been pondered upon for thousands of years.
 
  • #3
dst
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If there was a large shift in the atoms making up your brain, you would come to know about it.
 
  • #4
G01
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The fact of the matter is that yes, the atoms making up your body regularly change.

Whether this means you are a different person or not... Well, take that question to the philosophy forum.
 
  • #5
arildno
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Atoms that comprise your body are not atoms that you "carry around" with you throughout your life. Instead, the atoms are constantly being replaced by other atoms, and so the implications of this, is that if you go back say 10 years ago and recall a certain place where you were, the reality is that you really were NOT there, because every atom in your body has been replaced with something new?
The overturning rate is so small that it is perfectly acceptable to say that you, as a continuous existence persists.

Does a lake exist? A river?
 
  • #6
dst
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The fact of the matter is that yes, the atoms making up your body regularly change.

Whether this means you are a different person or not... Well, take that question to the philosophy forum.

Technically no, though. It's the structure and other things that matter, not the building blocks. Take a benzene atom, knock out one of the carbon atoms, and replace it with another - any difference? No. Unless every such atom is 'unique' then there is no difference whatsoever.
 
  • #7
G01
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Technically no, though. It's the structure and other things that matter, not the building blocks. Take a benzene atom, knock out one of the carbon atoms, and replace it with another - any difference? No. Unless every such atom is 'unique' then there is no difference whatsoever.
I never said the structure didn't matter. I was just answering his question. The atoms do change. As you say that isn't important, but, still, it was the answer to his question.
 
  • #8
dst
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I can't believe this question is considered 'unsolved' after thousands of years. Then again, some 5,000 years after earliest dated civilisation began, I still have to wipe my own arse.
 
  • #9
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On the other hand, according to quantum mechanics, the individual subatomic particles are indistinguishable, so you can't precisely say whether it is a different one or not.
 
  • #10
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Your hair will still grow back if you cut it. The source of new hair molecules will come from food. Food will be grown elsewhere, and so on. If you die, the atoms in your body will disperse in the environment and will be used by something else, maybe plants, trees or bugs. It's even possible that some atoms in our bodies were used in dinosaurs 150 million years ago. Everything gets recycled.
 
  • #11
Evo
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Perhaps this will help.

http://www.hhmi.org/cgi-bin/askascientist/highlight.pl?kw=&file=answers%2Fgeneral%2Fans_025.html [Broken]
 
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  • #12
Kurdt
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Your hair will still grow back if you cut it. The source of new hair molecules will come from food. Food will be grown elsewhere, and so on. If you die, the atoms in your body will disperse in the environment and will be used by something else, maybe plants, trees or bugs. It's even possible that some atoms in our bodies were used in dinosaurs 150 million years ago. Everything gets recycled.
You could even had atoms part of you that were once part of Einstein or Rutherford or anyone else you care to think of. However you'll probably never know. :smile:
 
  • #13
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You could even had atoms part of you that were once part of Einstein or Rutherford or anyone else you care to think of. However you'll probably never know. :smile:
True in general but there however an exception. There is alot of dinosaur bones in China, and it turned out the Chinese have been grinding them to make a dino soup. What an excellent calcium supplement.

http://www.foxnews.com/story/0,2933,288044,00.html
 
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  • #14
DaveC426913
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Question: do the neurons in your brain replace their atoms regularly? I know neurons don't regnerate, but do they replenish their atoms?

If not, then they literally are the same memories from 10 years ago.
 
  • #15
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Yeah, I was wondering the same Dave. I think that at an atomic level, sure they must replace I'd think, because of the mitochondria doing their job.
 
  • #16
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Well no crud Kurdt! LOL, thats mid-school learnings. Like the fact that the water you drink has been blood, urine, etc. etc. etc. LOL
 
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  • #17
Danger
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I still have to wipe my own arse.
What?!! You don't have a machine for that?! Peasant.
As I mentioned in another thread a few weeks back, in every breath you inhale several million, or possibly billion, atoms that comprised the body of Julius Caesar (or any other historical figure that you care to use). It's whatever retains the integrity of you that matters.
 
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  • #18
Kurdt
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Well no crud Kurdt! LOL, thats mid-school learnings. Like the fact that the water you drink has been blood, urine, etc. etc. etc. LOL
I'm not a homework helper for nothing you know. :tongue:
 
  • #19
Danger
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I'm not a homework helper for nothing you know. :tongue:
What??!!! You're getting paid for this?!!
 
  • #20
Kurdt
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What??!!! You're getting paid for this?!!
Due to the fact that my insights are the most valuable. :biggrin:
 
  • #21
Danger
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Due to the fact that my insights are the most valuable. :biggrin:
I'm not sure that I want to know what your insights are. If it's anything like a 'snappy comeback', that only applies if you have a rubber on too tight. (Hence the term 'anticlimax'.) Anything involving your eyes, I don't want to hear about...
 
  • #22
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Question: do the neurons in your brain replace their atoms regularly? I know neurons don't regnerate, but do they replenish their atoms?

If not, then they literally are the same memories from 10 years ago.
I'm no neuroscientist, but I had heard several years ago that neurons do regenerate to a degree, but it's just a really long time. Here are a few sources.

http://www.pnas.org/cgi/content/full/100/13/7430" [Broken]
http://www.sciencemag.org/cgi/content/summary/282/5391/1018b" [Broken]
http://www.jneurosci.org/cgi/content/full/17/13/5206" [Broken]
 
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  • #23
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I told my wife that on account of all my atoms being different, that I'm not the same person that signed that marriage certificate 18 years ago. What's more, I've gained quite a few atoms around the waist. She patiently explained that even if not a single atom persisted from that day, I am still the same handsome hunk that stole her heart away. I love it when she talks science.
 
  • #24
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Question: do the neurons in your brain replace their atoms regularly? I know neurons don't regnerate, but do they replenish their atoms?

If not, then they literally are the same memories from 10 years ago.
As I was reading the earlier posts I was thinking about the same thing. I know that most cells (presumably including neurons) carry out chemical processes fairly often, requiring them to dump waste compounds and take up new ones on a regular basis. After all, there's a reason that the brain needs a constant supply of blood. And we know that neurons constantly make new synaptic connections. So yes, I suppose neurons do undergo a process that one could call "replenishing their atoms."

But as NeoDevin already pointed out, quantum mechanics dictates that atoms and subatomic particles are indistingushable. There's no way to place a stamp on an individual atom or molecule. Memories are stored chemically, and even if the atoms that comprise these memories change, the difference is completely irrelevant. This renders the philosophical issue moot. To state that the human soul or self-identity can be "stored" in a group of atoms would be a pretty meaningless statement if we stipulate that atoms are indistinguishable.
 

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