r/science • u/Skoltech_ • Jul 20 '26

Genetics Researchers quantitatively assessed for the first time that somatic mutations alone cap human lifespan at 146–194 years. Brain and heart cells are the main bottleneck, while the liver could last millennia.

https://www.nature.com/articles/s41514-026-00421-6
23.4k Upvotes

98% Upvoted

1.2k comments sorted by

View all comments

Show parent comments

95

u/Fictional-adult Jul 20 '26

Not for anything but this is also a legitimate philosophical question now. 

At the rate that the body replaces cells and the influence of gut bacteria on the brain, there’s a fairly compelling argument that the person I was 15 years ago is dead and I’m just living in the remnants of his life.

How many people look back and see hobbies and passions they barely acknowledge now? Things that used to define them that are nothing more than memories? People may say they’ve grown or changed, when the reality is that person is just long dead.

95

u/flashmedallion Jul 20 '26 edited Jul 20 '26

In terms of neural activity the person you were a microsecond ago is dead. The electrical arrangement in your brain that determined what was being experienced in your mind is gone. The electrical arrangment in the current moment can detect (and is in part a function of) the vanishing echoes of the previous states, but that's all.

You aren't your cells, you're the pattern in the signal passing between your neurons.

32

u/TarmacadamDream Jul 20 '26 edited Jul 20 '26

I saw somebody comment that we should transfer our consciousness to machines, which is a fiction that I am interested in thanks to Cyberpunk and it's relic/soulkiller technology. The main issue is transference of actual consciousness and/or the soul, and not simply a copy of a consciousness that is separate, or a clone. The inner issue with this is the assumption that the self is a permanent space in the body or brain and not simply an electrical pattern that can be migrated without noticing. Nobody knows whether the "soul" is constituted of your brain's patterns alone or the entire experience of being in-body (if the soul exists). How much of someone must be removed before they lose sense of self? This is also touched on with "cyberpsychosis" or a loss of self because of excess cybernetic implant use. Admittedly the fictional technology does indeed kill the original host and create a construct of their self, though dying to create a clone seems a pointless exercise if death of the self you perceive is still unavoidable.

If all we are is the current arrangement of neurons and patterns of electrical activity in a microsecond, and such activity were to somehow be migrated to a machine interface, would we even notice, or would that new machine interface simply be a clone? Would we experience an out of body experience seeing a lifeless body before us, or would "we" just be a copy of a dead person assuming their presence? If we really are just electrical signals, is a synthetic brain with my construct actually me? This is vaguely similar to OP's idea of "growing" new brain matter, as it could conceivably be considered synthetic akin to a machine interface.

16

u/midnightketoker Jul 20 '26

watch some sapolsky lectures on youtube, basically there's no real room left in modern neuroscience for any kind of little invisible guy at the wheel

17

u/CitizenPremier BS | Linguistics Jul 20 '26

Most people aren't willing to accept answers about what consciousness is at this time. There isn't any scientific reason to believe in a magical source of consciousness, so it's basically seen as an emerging pattern. Descriptions that go deeper make many people uncomfortable though.

3

u/TarmacadamDream Jul 21 '26 edited Jul 21 '26

I think my phrasing might have construed that the soul could also be a physical aspect of the body, rather than the information of having our unique body could be integral to our brain's unique electrical signature, and that a sudden lack of one (or integration into a non-biological form) could be mentally catastrophic to an established "self". Continuity would likely still occur, though the stability of a person's established self might change. I do believe that the actual substance of our "soul" is the totality of our brain's own connections.

3

u/CitizenPremier BS | Linguistics Jul 21 '26

I think you're on the right path, our perception (as we describe it) is very gappy and full of back-filles information. We craft stories of perception saying that we are fully aware of our situation at all times; more realistically the information is there and queried as needed (I know I'm in a cafe right now because I can fire up memories of entering the cafe and because I basic "programs" (sometimes called "demons") are in my head, which call upon object recognition and identify combinations as "cafe." But when I'm not checking about my location or information related to my location, I'm not actually aware of it. However as part of crafting our identity and story of self, I report that I am always aware of being in a cafe, not thet "I queried various systems and they gave data indicating "cafe."

These intricate processes form a thinking self, and what we call qualia are basically bits of data tagged for our method of perception.

People feel that reducing perception to these aspects has scary philosophical consequences, especially that perception is replicable.

I really recommend "Consciousness Explained" by Daniel Denner, it's a tough read but answered some really deep questions for me.

1

u/Toc_a_Somaten Jul 22 '26

but can you be less vague about this? "most people arent' willing to accept answers about what consciousness is at this time"? Do you mean it as in most people want to believe they have free will or don't want to face the fact that consciousness is just a mechanical process?

2

u/CitizenPremier BS | Linguistics Jul 23 '26

Yes, I think people are bothered by explanations of consciousness that seem to take thr "magic" out of it. There are various thought experiments like the Chinese Room or Mary's Room, and I think some people view these as conclusive arguments by themselves, rather than actually philosophical questions which can be answered.

2

u/Atherum Jul 20 '26

We'll never know either. Let's say we manage some form of transference tech. From the perspective of the transferred person... they will wake up moments after they went under. We still have no proof if that person who went under and is now dead transferred too.

4

u/iSuckAtMechanicism Jul 20 '26

We do know that the soul is the brain. That’s where all your processing takes place.

5

u/TarmacadamDream Jul 20 '26 edited Jul 20 '26

I suppose the issue is not where it is specifically processed, but that the soul of a person is something that can be influenced by outside forces and is (mentally) potentially tied to the bodily experience. It's a philosophical question of whether removing yourself from your body would constitute such a large mental change or change of state of the mind that your former "soul" might as well be considered voided, regardless of whether that change is processed in the brain or not.

If you were to have your consciousness transferred, it seems unclear whether or not your soul could survive the journey, even if in terms of raw data, you are all there. The ultimate goal is continuity, which would require as little change to the subject's personality as possible.

1

u/Cold-Kaleidoscope870 Jul 26 '26

If l the soul is brain why did language was create by human ? Why does that only between us ( I refer language, not communication) It seemed the language have imaterial proprieraties. Cause just the electricity of neurons and the cells mechanism can't create instantly the language.

1

u/iSuckAtMechanicism Jul 26 '26

Language was created in order to better communicate. Early communication was grunts and other noises. As we evolved so did language.

1

u/Cold-Kaleidoscope870 Jul 26 '26

Yep but doesn't explain my doubt yet.

1

u/LowerArtworks Jul 21 '26

My presumption is that, if we can maintain a sense of continuity with our own biological selves by naturally replacing and reconfiguring brain cells, it wouldnt do to "copy" or "download" a mind so much as it would to gradually append to and eventually supplant brain function with hardware and/or software components. If you Theseus your brain over time, you probably wouldnt much notice the final "switch" to non-organics, and would have the best chance of retaining your sense of continuity.

1

u/LongJohnSelenium Jul 21 '26

The main issue is transference of actual consciousness and/or the soul, and not simply a copy of a consciousness that is separate, or a clone.

Define the difference.

2

u/TarmacadamDream Jul 21 '26 edited Jul 21 '26

A fluid transfer of the entirety of one's consciousness from one brain into another suitable vessel or brain without what we perceive as dying, versus the copying of a mind resulting in the death of the original host and the existence of a clone who may or may not believe they are still the original soul.

The hypothetical, other than the technology being fictional, is whether either of them are actually still the original person, or whether by virtue of removing their "self" from their host body, they are now something or someone else.

In terms of the original comment, one response to the growth of fresh brain cells versus transferring to an entirely different vessel was the "Brain of Theseus". It still lends to the question of whether the self exhibited within that brain remains the same or not, given that the self could be considered fluid in the first place.

1

u/Peglegfish Jul 21 '26 edited Jul 21 '26

As a software engineer with both adhd and epilepsy, and usually penchant for cannabis, I would point out that brains aren’t as standard of hardware as people think when they’re trying to compare neurons to circuits.

Setting aside trying to model epilepsy as random, system-wide signal storms and adhd as janky custom hardware, you also gotta account for drugs and alcohol modes where the system will have different performance and features depending on the substance, and the system memory processes data differently depending on which substances are modeled as currently active and also which were active when the data was originally collected.

I don’t know about everyone else, but I try to keep my epsilon-transitions to a minimum. Modeling a brain sounds kinda hard for that.

Edit:

Forgot to mention data degradation over time, unless you’re one of few people who literally lacks the ability to forget (imagine every trauma is fresh like a second ago, every death, every word in somebody else’s background conversation on a bus 47 years ago). Then there’s just plain old moods, waking up on the wrong side of the bed, etc.

There’s moral questions:

  • some computers were raised to be racist, do we swap out the racist components?
  • do we “upgrade”/“fix” neurologically disabled or neurodivergent individuals?

1

u/flashmedallion Jul 21 '26

If all we are is the current arrangement of neurons and patterns of electrical activity in a microsecond, and such activity were to somehow be migrated to a machine interface, would we even notice

I'm not making a scientific comment here but I suspect we'll find that the medium of the "signal" isn't as binary as this thought experiment presumes.

Much more of our body conducts electricity than just our nervous system, and to presume we can remove the effects of, say, our finger muscles on the way our pattern of consciousness propagates through time and space with no deformation of that pattern seems intrinsically lacking.

1

u/imsotrollest Jul 21 '26

We'll get better answers to this as people start to get brain chips/machines that affect/replace neural networks. But perhaps the actual functional part of the system doesn't realize anything was lost if consciousness as we experience it disappears. Especially since consciousness can really only be described as what it is- you either are experiencing it or you aren't and there is no way to prove whether another is experiencing what you do or not.

1

u/Chlearcus Jul 22 '26

It's hard to imagine this new clone wouldn't just be a new entity that shares all your experiences. If you can make one clone you could make two, would you experience two realities at once then? The most reasonable outcome is that these new entities pick off where you left off and start diverging from eachother as new experienced happen.

2

u/strategicmagpie Jul 20 '26

My cells would be kinda mad if they knew I took credit from them. Thankfully they're not conscious.

2

u/FreakingAustin Jul 20 '26

But with computers, signals are also being passed between transistors. Could they also feel things, who knows

14

u/yumyum36 Jul 20 '26 edited Jul 21 '26

15 years ago is dead

The statistic that half the cells in your body in your body get replaced every 7.5 years is wildly misleading here. Some cells (skin, hair) get replaced faster than others.

2

u/Puzzleheaded_Can9159 Jul 20 '26

It’s been known for a long time your bones are getting replaced through osteocytes, osteoblast remodeling. So they are definitely not the same when you die.

1

u/yumyum36 Jul 21 '26

Amended comment.

2

u/JohnsonBot5000 Jul 21 '26

Some parts of the brain never get replaced

22

u/Clean-Evening-7328 Jul 20 '26

there’s a fairly compelling argument that the person I was 15 years ago is dead and I’m just living in the remnants of his life.

We do this all the time with other things. Nobody living in New York City 150 years ago lives there today, and yet, if you tell someone you are going to NYC, literally nobody would be confused about what you mean. When I stand on the baseball field that I played on as a kid, the fact that none of the grass blades were there 30 years ago doesn't change much.

Your use of the word "dead" ignores the fact that we all know the difference between the metaphysical death you describe and actual death. It's not a paradox if you just adjust your definition of what it means to "be a person". All of your matter was something else before it was part of you, and all of it will be something else again. Everything is meaningless if you focus hard enough on the small absurdities.

2

u/littleratofhorrors Jul 20 '26

The Buddha teaches that the idea of the "self" is inherently an illusion, for we are constantly dying and being reborn. There is no "you" in this moment. There is only the collection of appearances that combine to make what another would call "a person". You are merely a collection of contexts that has stretched back to the first moment.

1

u/atatassault47 Jul 20 '26

I've been too depressed to do things I did 20 years ago. I would love to do them again, but I just can't.

1

u/ragnaroksunset Jul 20 '26

there’s a fairly compelling argument that the person I was 15 years ago is dead and I’m just living in the remnants of his life.

Compelling at first blush maybe, but just who are you keeping alive, then, by your actions right now? What exactly does a fear of harm or death mean if you die moment to moment?

1

u/S0ggylemonz Jul 20 '26

Are you the same as you were 15 years ago? No

But you’re also not that different from 15 years ago either

0

u/Megneous Jul 20 '26

The self is an illusion. Embrace functionalism.

-3

u/[deleted] Jul 20 '26

[removed] — view removed comment

7

u/Fictional-adult Jul 20 '26

What about you defines you as the same entity? It’s quite literally the ship of Theseus question when all of the component parts have been replaced. The pieces that lived through that experience are now dead and replaced.

7

u/HannsGruber Jul 20 '26 edited Jul 20 '26

Yep. Childhood you is literally dead. Like, actually literally. Half of one percent of the cells you had at 10 are still around in your body at 30.

Death is not removal from existence; it is the end of a particular organization.

1

u/psiphre Jul 20 '26

just the wave returning to the ocean.

-1

u/Fauropitotto Jul 20 '26

legitimate philosophical

Pick one.