If 98% of the atoms in our body are replaced in just 1 year, what are we?

[Betwrong]

Well, we are different from what we were 1 year ago, that's for sure. Actually I like the theory which suggests that we are different every new day of our life. I'm not saying we have our mind changing completely, no, but there is always a slight difference from what it were a day ago.

[kryptqnick]

A well known study, published more than 60 years ago (Paul C. Aebersold, Radioisotopes — New keys to knowledge, p. 219
https://www.archive.org/stream/annualreportofbo1953smit/annualreportofbo1953smit_djvu.txt) concluded:

"Tracer studies show that the atomic turnover in our bodies is quite rapid and quite complete. For example, in a week or two half of the sodium atoms that are now in our bodies will be replaced by other sodium atoms. The case is similar for hydrogen and phosphorus. Even half of the carbon atoms will be replaced in a month or two. And so the story goes for nearly all the elements. Indeed, it has been shown that in a year approximately 98 percent of the atoms in us now will be replaced by other atoms that we take in our air, food, and drink." (p. 232).

Even if we accept this conclusion, it isn't clear for how long the last 2%, comprehending heavier elements, can subsist on the human body and if at least a small part can stay in our body until we die.

The Internet is full of stories on the issue, saying that all of our atoms are changed on a time frame of 5 to 9/10 years. But none of those articles quote any other scientific study. I couldn't find any study asserting a 100% change or its time frame. But since this isn't my professional field, I didn't exhaust the sources.

The same can be said about books that claim a 100% change between 5 and 10 years [for example, Richard Dawkins, The God Delusion (London, 2006), Chapter 10, p. 371, just quotes Steve Grand, Creation: Life and How to Make It, that tries to explain his conclusion on more or less common sense:  https://stevegrand.wordpress.com/2009/01/12/where-do-those-damn-atoms-go/].

But if we accept the conclusion that in only one year 98% of our atoms are changed, perhaps the percentage goes over 99% after some years more. And that has consequences about our identity.

Saying that our atoms change doesn't mean that also our cells change entirely. Cells can repair themselves and discard molecules and atoms without dying.

The best candidates to survive across our life are the neurons, even if we have other cells that survive more than 15 years (some cells of the muscles, especially the ones from the heart, and even of the gut).

However, the classic theory stating that the body didn't create any new neurons since birth it's no longer the state of the art.

It seems now accepted that many neurons die daily, but that also neurons are created and the brain can even regenerate within certain limits from an injury. There exists now ample evidence about the creation of neurons on the hippocampus.

If the number of neurons didn't increase since birth, we couldn't explain the increase on the dimensions of the brain as children grow up.

But it's still controversial if also new neurons of the cortex are created. The evidence is pointing on a negative sense.

See, for example, Kirsty Spalding et al., Dynamics of Hippocampal Neurogenesis in Adult Humans, Cell, Volume 153, Issue 6, 6 June 2013, Pages 1219–1227 (available at
https://www.sciencedirect.com/science/article/pii/S0092867413005333); D. Gentleman, Growth and repair after injury of the central nervous system: yesterday, today and tomorrow (Injury 1994, DOI 10.1016/0020-1383(94)90030-2: available at http://thirdworld.nl/growth-and-repair-after-injury-of-the-central-nervous-system-yesterday-today-and-tomorrow ; Tim Requarth, How Brains Bounce Back from Physical Damage, After a traumatic injury, neurons that govern memory can regenerate (2011): http://www.scientificamerican.com/article/how-brains-bounce-back/ ; Fernández-Hernández, Rhiner C.-New neurons for injured brains? The emergence of new genetic model organisms to study brain regeneration, Neurosci Biobehav Rev. 2015 Sep; 56:62-72. doi: 10.1016/j.neubiorev.2015.06.021. https://www.ncbi.nlm.nih.gov/pubmed/26118647 (just abstract); https://www.newscientist.com/article/dn23665-nuclear-bomb-tests-reveal-brain-regeneration-in-humans/.

Therefore, it seems that almost all the atoms on our body change, but there are at least some cells, the neurons of the cortex, that aren't replaced during our life.

Anyway, even if only 98 or 99% of our atoms were replaced, this is enough to force us to ask what is our identity's basis as individuals?

Our current body is mainly just a clone of the one we had 15 or 30 years ago. Even if the neurons of the cortex are the same, it seems that almost all of their atoms were replaced. So also they are just clones of itself.

The I that writes this, on the atomic level, has little to do with the I that register this account on Bitcointalk about 3 years ago.

If we don't seem to have a specific material support, the idea that we are our body ends up in open crisis.

Let's forget about any "soul" for the reasons stated here https://bitcointalk.org/index.php?topic=1424793.0

We can't also support an identity on our memories. An individual with amnesia doesn't cease to be that individual.

Moreover, memories usually can't be trusted: just watch again an old movie or read a second time an old book; rarely will it be exactly as you remember; sometimes, the differences are staggering.

If many of our neurons indeed are replaced (that seems to be clear on the hippocampus, but it is decisive mainly on the formation of new memories), our memories might be memories of memories. Copies of previous memories.

We can't also say that our identity is directly linked to our conscience. We don't cease to be a specific individual because we are in a coma or on a sleep without dreams (I'm not going to enter the discussion about deciding if we are aware when we are dreaming).

So, what are we? Obviously, we are a specific DNA (no one has exactly my DNA), since not even identical twins have an exact copy of their DNA, there are very slight differences (for instance, fingerprints are different).

It's the DNA's importance for our own individuality that makes cloning a so controversial issue.

As specific individuals we are mostly determined by our neurons and these are determined by our DNA. But we are not only our DNA.

We are more than our neurons. Many of our characteristics are mostly determined by the synapses neurons create between themselves.

As far as is known, these synapses are determined also by our DNA, but as well as by our environment: the quality of our education, our habits, our personal experiences, etc.

Children raised by animals aren't able to even use their hands (https://theweek.com/articles/471164/6-cases-children-being-raised-by-animals). Probably, a neural exam would show very low synapses on many decisive zones of their brain.

Therefore, another being that has a copy of our genes won't clearly be us. He won't have the same synapses, since many are created by specific experience.

But even those synapses are simple a form of organization of our neurons.

This means that we are mainly a specific pattern of organization of any atoms and molecules.

Let's accept this conclusion and think about the so-called theoretically possible upload (usually, people write download, but, of course, we are the sender, so it's an upload) of our brain to a machine.

Of course, this is still impossible to do. But just follow me on the theoretical consequences of this on our identity.

If we uploaded a copy of our neurons with all of their synapses to a machine we would be uploading all of our memories, personality and mental capacities to the machine, since all of this is formed and conserved on our neurons and their connections.

Would the machine become us?

The answer is a clear no. The machine would be just a digital super-clone of us; we would be the original. He would be only a copy. We would still be an autonomous individual from our artificial super-clone.

But imagine that all our cells are replaced by artificial cells, including our neurons and their synapses. One by one, our cells would be replaced with some kind of artificial cells.

Imagine that the process was a slow one. We would be aware, as our neurons were slowly replaced. Perhaps during some days, perhaps during a few hours.

We would end up doing what our body does more or less in one year (or more) at the atomic level, but with a change of the nature of our cell's physical elements. We would cease to be beings mainly of oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus, to be made of some other elements.

During the time of the transformation, our natural body would be slowly killed, more or less as our own body slowly dies with the dead and replacement of most of its cells with new cells.

But in the place of the old body we would have a new one, with an exact copy of our DNA.

On the end of this transformation, would the new body be us or a clone?

Since we are already natural clones of our previous bodies, it seems it would be us as well as we are us now, compared with the body we had several years ago.

Would you do this transformation on your free will, to be healthier? Probably, no.

But we would do it for sure to avoid certain death.

Is this our future?

Philosophy usually deals with this by adding that apart from those atoms we also have another substance which is our mind. Our mind is less changeable. Our identity is actually more about mind then body

[valta4065]

The only logical answer is: memories.

We are what the atoms of our body remember from what we were before.
That's not nothing though, each atom replace another one and keep something from it: a place, a velocity, a matter...

[ObscureBean]

I've read your post and I believe I've understood the crux of your proposition/musings. Correct me if I'm wrong but you're basically looking at possible ways to extend human life. May I ask, why do you seek to avoid death? I'm not saying that you should court death but what's so terrible about (for example) dying of old age?

[Trading]

I already answered to you about that issue here: https://bitcointalk.org/index.php?topic=1221052.msg15070414#msg15070414

But I'm going to repost the full justification that I posted here: https://oneskeptic.tumblr.com/post/146726224082/on-death


"Since there can’t be any immortality, and death is our destiny, unfortunately, the issue of the effect of immortality on the value of time can’t be really tested.

Clearly, being able to live thousand of years would lower the value of our time. But I surely wouldn’t mind to have time to be able to real waste it.

You could tell yourself that you would be ready to die, after having a meaningful life. But that is just rubbish.

Or write, like Mark Twain, that death is as just natural as life, implying that we have to accept it as we accept life.

But this is also absurd. Death is natural, but it’s the end of life.

Let’s deal with death with a laugh, but saying that it must be a pleasant one is nonsense or proper of people that don’t give enough value to their limited time of consciousness.

Even being death “natural”, it doesn’t cease to be coercive.

Imagine a world where everyone is forever young, except your self or your child. Wouldn’t that be terrible? Does the simple fact that death happens to everyone makes it something you must accept with a sincere smile?

Think about kids that have Werner syndrome, Cockayne syndrome or other fast aging disease. Does the tragic nature of their condition results from the simple fact that are rare situations and, therefore, “unfair” to them?

Mark Twain wrote as well that we also didn’t have any opinion about living, it was also imposed.

Actually, that is not exactly true; a part of us had literally the run of his life to live, the spermatozoid. Every one of us is a victorious being that won the prize over millions of others.

Being afraid of death is more than understandable. It’s logical.

Someone who doesn’t fear (or, at least, feels negatively) death is someone who doesn’t love anything in life, not even himself.

In the end, the only positive way to part from this life would be if we were completely bored with it.

Think about it: life is like a relationship, the only happy way to end it is if we were tired of it. If we still love it, death will always be a tragedy.

Besides, being able to make our own decision to end life is also a positive thing. Death wouldn’t be imposed by nature, but would be our own decision.

One of the major problems of death is that is imposed on us against our will.

Of course, parting this life because one is bored with it wouldn’t be exactly a happy moment. But it might be less unhappy than to parting it when we are still in love with life.

The problem is that a lifespan of 100 years, at best, is not enough to have any conditions to reach the goal of getting bored with life.

It’s impossible to determine how much time we would have to live in order to start feeling really bored and willing to die.

But if suicide is the less oppressive way to die, I think I probably would need many thousand years to start thinking about it.

Of course, I’m not making an apology of suicide. If I was able to chose the way to die, I would chose suicide, but because that would allow me to be a master of death and, so, to live thousand (or million) of years.

Suicide makes sense only if living is a real pain. Because of physical pain; or because of unbearable boredom.

In our current conditions, where life is a blink of an eye of awareness, in between two eternities of being nothing (before being alive and after being dead), suicide seems absurd.

But the only less bad way to die would indeed be suicide; after a very, very, long life.

Unfortunately, currently, that isn’t yet available. We have a short lifespan. There is little hope to get bored of life.


So, better enjoy our luck to be alive like if we had a chance on a trillion of quadrillions to be born, since our actual odds were even worst than these.


Make the most of life like if it was a single drop of water tumbling on our thirsty lips on an infinite desert.
  

Value every day of it as if we were on a death row, because we are; we just have a wonderful, huge, cell and no one told us yet when it’s going to be our turn. "



Anyway, you have the interesting/original opinion, not me. My profound dislike of death is very common.

Very few people like to live in a wonderful death row.

[iTradeChips]

using knowledge of physics, biology and latest neuroscience, i would say we are just a dance. the thing we call "self" is just a convenient fiction.
a pattern from the very complex chemical soup that is the human body.

[Trading]

In the end, we are made basically of quarks (base of the protons and neutrons which form the atom's nucleus) and electrons.

As far as specialists know, both quarks and electrons are elementary/fundamental particles, made of "pure energy" (perhaps, composed by the famous strings). All its mass is created by the Higgs field because of the way they interact with Higgs Bosom.

These kind of particles have been compared not to a violin, but to the sound/vibration that the violin makes.

That seems what we are: a specific pattern of organization of energy.

But this is the easy part.

Things only start to be really bizarre when we think about what these particles that are part of our body can do according to quantum mechanics.

If the subatomic particles of my (temporarily) atoms can be at different places at the same time, am I also (of course, not conscientiously) at different places at the same time?

[RealBitcoin]

Unique configuration of neuron synapses in the brain.

[Trading]

I dont get the topic of this thread at all
what do you mean that 98% are replaced,ok let's say it is really happening but tell me ,what does replace them ? LOL

 The idea being that atoms are replaced like with like.

You mean our atoms are being replaced with any other ones?
So we are becoming not human but something randomly else? wtf is this thread actually,i still dont get it lol

As cells die, they are expelled from our body (so, their atoms are expelled). New cells are made from matter (atoms) that we incorporate (oxygen we breathe, food we eat, liquids we drink).

Even the neurons' atoms are replaced as they repair themselves. Probably, by expelling old molecules and creating new ones.

By this process, all our atoms seem to be replaced by new atoms of the same type.

We are just natural clones of ourselves.

[RealBitcoin]

Identity = your unique brain neuron configuration + your unique genetic material.

Why is it so hard to comprehend?

[BADecker]

Identity = your unique brain neuron configuration + your unique genetic material.

Why is it so hard to comprehend?

Electrons are aether eddys. They ALL change every nanosecond. You folks are so behind the times.

[groll]

We will still be ourselves.  Because the one being replaced is just the same amount and same thing.  God is so great, he knew everything.  He knows how much hair we have, how much atoms it is needed to make us.  So even if the atoms in our body will be replaced in just a year we will still be the same.  And I do not think that it will not happened as everything in us is not an accident.

[Trading]

Identity = your unique brain neuron configuration + your unique genetic material.

Why is it so hard to comprehend?

Electrons are aether eddys. They ALL change every nanosecond. You folks are so behind the times.

About the nature and composition of electrons we have nothing more than theories.

Anyway, without a link to a credible source (sorry, not the good book), your post is just words.

[Trading]

Identity = your unique brain neuron configuration + your unique genetic material.

Why is it so hard to comprehend?

No argument from me on that. But we are just clones of ourselves and that is a subject worth thinking about.

[Tyrantt]

There is a video from CrashCourse on that theme.

I believe it's one of these:

https://www.youtube.com/watch?v=GxM9BZeRrUI

https://www.youtube.com/watch?v=3SJROTXnmus

[groll]

Well, we are different from what we were 1 year ago, that's for sure. Actually I like the theory which suggests that we are different every new day of our life. I'm not saying we have our mind changing completely, no, but there is always a slight difference from what it were a day ago.

I agree with you, some part of ours changes maybe everyday.  It maybe not that obvious but something changes.  Like of course we know that we aged and we become weak.  It is true because if there is no change then we still all are babies until now.   But seriously, everything grows on us our hair, our nails, we have changed our skin like that it is just slow process.  It is timely and well planned.

[Trading]

I prefer this one: https://www.youtube.com/watch?v=17WiQ_tNld4

[Trading]

On my post about atheism (https://bitcointalk.org/index.php?topic=1424793.0), I wrote that we were nothing for an eternity and will be again nothing for another eternity after our death.

However, if we accept that the quantum fields (see https://bitcointalk.org/index.php?topic=1221052.msg14388816#msg14388816) that created all the stuff (matter, energy) and this universe are eternal and will keep creating stuff forever (search A Universe from nothing), like supposedly they did in an eternal past, then, after almost an eternity, they will create another universe exactly like ours, with an Earth like this and with you and me, writing again on this forum.

Actually, in the past, there must have been many of you and me.

At least if we accept that what is me and you isn't an exact body (like explained on this OP), made of some specific atoms, but a pattern of organization of them (a DNA and the particular synapses of your brain).

Some argue that there are infinite universes, constantly popping out from new Big Bangs (search for Eternal Inflation) and, therefore, there must be a universe like this one, with another you and me. But this theory is very controversial, much more than the idea that the quantum fields are eternal.

Anyway, some argue that there might be other yous and mes living a different life. However, that would be much harder to happen.

We were the result of a specific egg and spermatozoid. Any difference on our universe past and we wouldn't exist. It would be enough a few different seconds on the life of one of our billions (including non human ancestors) of ancestors to a different child to born, changing necessarily all our ancestors chain.

For us to be living a different life would be necessary that all the past of a copy of our universe to be exactly the same of this one up to us and then we would change something in our life.

For us to be born again, it will be necessary an universe exactly like this one since the beginning, 14 billion years ago, with the same exact mass down to the quark, created out of chance.

How likely is this to happen? After death, at best, we'll be nothing again for a zillion of trillions of years... but after this long, we'll live again, without the conscience of the lots of me and you that lived before.

But, at least, we'll live again and again and again. After all, it seems we are eternal!!

We'll just have to wait almost an eternity between each life.

[Trading]

Beside theories that argue for eternal inflation, infinite Universes or that our Universe is infinite, also theories that argue that our Universe is going forever to explode on a Big Bang and then return on a Big Crunch (Big Bounce: https://en.wikipedia.org/wiki/Big_Bounce) are compatible with the idea that there will be more universes exactly like ours or that there are already Universes like ours with another us.

In short, every cosmological theory that argue that the creation of matter is eternal are compatible with the idea that soon or later there will be exact copies of us.

[BartS]

What that tells me is that we cannot define ourselves completely by what we see and can measure, to me that tells me that whatever makes us a unique individual is not tied to the physical reality we can measure.