This discussion is now closed.

Check out other Related discussions

How much of you is still you?

As we are all constantly replacing cells etc in our bodies and getting rid of old ones I was wondering- How much of your body consists of the same components as when we were born? If nearly all of our cells and chemicals have been replaced by new ones (even if these have exactly the same structure as the old ones) then surely we no longer consist of exactly the same parts so would chemically no longer be the same person even if we were genetically and in memory.

Scroll to see replies

Reply 1

theoffender

I've had this thought before. So does this mean that I am literally a completely different person to who I was say 5 years ago?

Reply 2

Dajo123

Brain cells do not regenerate, so your brain stays the same, i think everthing else is replaced.

Reply 3

Wagamuffin

Well you can't exactly say all people remain identical for their entire lives. But it's probably too tricky to find out why because changes in "who you are" could occur because of the environment around you etc.

Reply 4

Adhsur

This is certainly an interesting topic.

It comes under philosophy as well as science - "the problem of the enduring self". Are you the same as when you were younger? If our bodies constantly change and so does our behaviour, how can we say that we are the same? Can you really point to a photograph and say "That is me"?

Reply 5

RobbieC

That is a scary concept. How long does it take for a full cycle of cellular regeneration to take place, on the epidermis?

Reply 6

Homegrownkitten

When you reach 7 years of age you are not the same person as you were when you were born (with the exception of brain tissue)

Reply 7

MadNatSci

Dajo123

Brain cells do not regenerate, so your brain stays the same, i think everthing else is replaced.

Actually your brain cells do keep replicating until you're about 20, I think. Then they start to die off :eek:

Yes, everything else is replaced sort of; but your DNA is still the same, so you're not a completely different person, and when your cells split for growth, after you've finished your main development, they split into two identical cells. Which one was the original? Answers on a postcard. Also remember the replication is semi-conservative so you possibly still have a strand of the DNA you had in your original zygote, somewhere... Who knows?

Personality wise though, you're definitely different from the person you were when you were younger: every experience changes you because you learn from it. In the end, I don't think there's a straight answer - my points above were just an attempt to generate some debate :wink:

I guess you could argue about this for years...

Reply 8

Hipocrit

Yep. after a seven year period not one of the atoms in your body is there that was there seven years ago (statisticlly speaking, brain tissue excluded).

Some tissues regenerate/die faster than others though. I wouldn't be suprised if your red blood cells were replaced every few weeks or months.

Reply 9

Wagamuffin

Gee this REALLY makes me wanna cut up my bone marrow for stem cells :smile:

Getting paranoid about le deathe de braine!

Reply 10

Jonatan

devilschild

Are you certain that the physical matter matters at all? Are you sure it is not teh state of the mind that determines which person you are.

Its quite interesting actually. If you coppied a person atom by atom. Would you then have two persons or two boddies containing the same person ?

If you teleported a persons body by sending one atom at a time, would the mind be left behind ?

Reply 11

MadNatSci

Jonatan

As a scientist, I'd say yes you would have two people who were excatly the same. They might develop differently from then on - but I believe your personality is contained entirely within your brain. Dunno how exactly, but one day I might try and look into it... :biggrin:

Reply 12

LS.

Think about all the drugs and medications you use. They change you - do they alter you from who you would be if you didn't take them? Are you a different person because you have taken them, then, are you not really you?

This was brought up last year in our RE class, heh, it really freaked some people out.

Reply 13

Barny

Adhsur

God, philosophy sounds shite :tongue:

Reply 14

Jonatan

MadNatSci

So if I teleported your body, woudl that mean that your mind tags along in the proces, or is your original mind destroyed and a new created?

Reply 15

gzftan

devilschild

I've heard something similar to this before....take a river...the water molecules in it are constantly moving and therefore the river is changing....is it the same river from one second to the next?

Too much thinking for me...i call a river a river and a person a person :smile:

Reply 16

MadNatSci

Jonatan

So if I teleported your body, woudl that mean that your mind tags along in the proces, or is your original mind destroyed and a new created?

Well yeah, your mind must tag along - at least it must do following my assumption above. If the mind is entirely contained within the neurons of the brain, you can't lose it when you teleport someone: you can't lose those neurons. Unless it was a crap teleporter :smile:

Reply 17

Jonatan

MadNatSci

But your brain is destroyed before it is put together again, so are you not merely destroying one mind and then creating one exactly like it ? How does the consciousness manage to fly from one body to another?

Reply 18

MadNatSci

Hmm, yes... but surely the idea is it's reassembled in exactly the same way at the end of the teleportation-thingummy-wotsit?

Reply 19

Unregistered

just to add a small rather random point:

many of your immune-system cells (memory cells) can stay in your body for awfully long periods - I remember reading somewhere about some study or other and they found 60-year-old memory cells in some old Japanese (?) people

I like madnatsci's point that in cell division you don't really have "new" and "original" cells..

rosie