/sci/ - Science & Math

It depends on how you define "are" "who" "you" "were". Which is philosophy, not /sci/ence.

You being still you is a question of semantics.

Psychologically speaking, you would still be you if your self is still coherent.

im pretty sure that's not how brain cells work

Osteocytes, for example, are totally locked in a matrix of bone matter and aren't constantly being replaced. The bone matrix itself is chemically stable and definitely is not replaced.

Bullshit. Liver cells for example can live 1 year without even dividing.
Sure lots of cells divide, lots of cells die but no you don't get 'replaced' completely.

But philosophical: Are you only someone else if you changed for 100%?

>>3983480

Uhh sir, bone is known to be very variable. Constantly rebuilding and replacing itself.

>>3983495
a fracture will remodel, but never be how it was.

>>3983495

I dont think you read this before replying.

>Osteocytes, for example, are totally locked in a matrix of bone matter and aren't constantly being replaced. The bone matrix itself is chemically stable and definitely is not replaced.

While cells constantly die and are replaced, all cells are not created equal. DNA becomes frayed at the ends with time, thats one reason our body ages. Newly created cells are not always as good as previous ones.

how do you retain memories?

If I recall correctly, nerve cells almost never replicate. Your brain is made up of mostly the same cells throughout your life, correct?

You are a proces, not an object. Any interruption to the process and you cease being you. Example would be extreme irreversible forms of memory loss and death.

>decades old model of atom
>science

i'm pretty sure that the matter making you up is changed.

but last i heard, this was a time period of ~7 years, and did not expressly mention cells but rather just the materials everything is made of

but to be honest, i don't remember it that well

>>3983453
First two sentences: yes.
Last sentence: full retard mode

>>3983504

I know, so what?

>>3983512

I did read it, but wrong. Excuse me for that, I thought you said: They don't replace.

>>3983530
An atom (or so people think, I think it's kind of nutty) is the smallest thing they (think) they can imagine. If you ask someone in the street what a quark or a neutrino or a gluon or whatever is, they wouldn't have the slightest idea.

I think it's kind of stupid tho, since most people can't really imagine how tiny an atom really is.

>>3983537

HURR DURR EVERY CELL REPLACES ITSELF BECAUSE IT'S RETARDED. Don't you see how this is energetically unfavorable? Cells can function for longer then 6 months without losing any of it's capability.

Even if the collection of atoms that composed you was completely constant, their configuration changes from instant to instant. The significant connection between what you identify as yourself from 1 second ago and what you consider yourself now is a narrative of how one changed into the other.

>>3983520

No, a cell will never duplicate if it's not exactly the same as what it was. Yes it may happen but then there are several processes to stop that. And if these processes fail we got another name for it: Cancer.

>>3983546

Yea as far as I'm aware Neutrinos are pretty much the smallest thing we know for sure to exist isn't that right?

>>3983529
>nerve cells
lol

also it depends on the type of neuron the ones in your olfactory bulbs die and replace themselves every few months, others you're stuck with
however while the cells may never die they do repair themselves with outside materials, so they probably Ship of Theseus themselves eventually

>>3983572

http://www.youtube.com/watch?v=bfUCqp66DDM

Its 7 years. That's why bad luck from breaking mirrors only lasts 7 years.

not neurons. so you are who you were last November.

>>3983568
The next time you talk to your dad, tell him "Dad, I cannot telomere."
He might say "Son, I am disappoint."

>>3983546
>people can't imagine things smaller than an atom
>that's why they use a model of the atom that shows electrons
lolokay

OP needs to read this:

http://lesswrong.com/lw/qx/timeless_identity/

>>3983595

That is not what I meant.

>>3983608

That is a very nice blog, thank you for the link.

>>3983612
It's probably our fault for trying to understand what you said instead of what you should have said. In light of that, I congratulate you on all of the well thought out and insightful comments that you would have ideally posted.

It depends and it doesn't matter.

Your cells are constantly changing, your atoms are constantly changing, on every level you are constantly changing.

First issue is that they are no like a snake changing its skin, a bunch of cells are going to die today, but others will be created. In case that data is right, in 6 months you are not like you are today, but during that transition, you had a little bit of the past. It's a flow, not something that happends over night.

The second issue is that we cannot say exactly what we really are, or in other words, we can say a lot of things that we are. We are atoms, we are space, we are body and mind, we are animals, we are machine. It's all correct. The water in your body changes much faster than in 6 months and you are mostly water, so what does it matter? If you zoom in at the edge of your body, where your skin ends and the rest of the world begins, you won't be able to spot a division line.

Fractals and shit. We cannot put our finger on the now, on us, on matter, on space, on time. We are atomic beings in the sense that atoms are indivisible, they are what we perceive as the common smallest thing that builds our bodies. In this way (not in the usual scientific way), cells are atoms, our mind is an atom, the touch of a hand is atomic even if at close sight nothing is really touching. Being atomic is recognizing we cannot reach a limit to what we are and so we accept that limit as the level we are looking at things. When you are touching a woman, who gives a fuck about cells? When you are studying cells, who gives a fuck about quarks? When you are studying atoms, who gives a fuck about you?

>>3983643

Yep

>>3983453
the human body does always create new cells as old ones die, but the body does not keep re-creating ALL the cells, nor does it re-create them at the same rate

the main cells constantly produced are red blood cells, which is the bilirubin that makes your shit brown
http://en.wikipedia.org/wiki/Bilirubin

some working surfaces of internal organs also have a very high rate of turnover, but other cells like those of the inner ear do not.

i dunno what the longest-living human cell is, but remember that womens egg cells can be impregnated when they are 60+ years old. it is not known what the outer limit on human egg cells is ,,,,,,, the problems with older women getting pregnant is other related but external physiological factors, not any problem of age within the egg cell itself

>>3983690

[samefagging my own DAMN post]

....so i guess really,,,,,, if you wanted to know how long it took your body to 're-create' itself, you could just weight yourself, and then weigh your shit..... keep a running total and when you have shit equal to your weight, your body would have created at least that much cell mass (more really, since some get out in yer piss + wacking off too)

>>3983706
No, that would be assuming a constant rate of replacement for all of your body's massive components. If you want a really obvious example of something that isn't replaced, look at the surface of your adult teeth.

Besides that, a significant portion of your exchange of matter with your environment is through breathing.

7 years.

>>3983453
Except for that part of being human is the whole eating and drinking and breathing thing.... Why did you think we do these things?

>>3983453
>>3983453
no brain cells generally speaking are permanent and there is no neurogenesis.

meaning that brain cells are approximately the same age as you.

inb4 hurr durr glial neurogenesis via astrocytes.

I lol'ed at the difference between
>no brain cells are permanent
and
>no, brain cells are permanent