[SirHumphrey]

>>> The person you are today doesn’t share a single cell with the version of you from seven years ago. (This is, of course, a generalization as some cells regenerate much faster and others a little slower.)

No, that is not even remotely true. Most of the neurons in the central nervous system (the part of the body one could argue does the most of thinking) stay mostly the same from adulthood to death[1].

[1]: https://en.wikipedia.org/wiki/Neurogenesis

[cwbrandsma]

That sucks, since I developed a neurological issue from Covid I could really use a refresh of my nervous system.

[dredmorbius]

Be careful what you wish for.

(With an understanding that where you are now undoubtedly sucks. My sympathies.)

[LPisGood]

I once heard that this is an oft repeated myth, that neurons are not replaced throughout life.

It seems to me to that what you said is true, but for some odd reason I have a recollection of reading a debunking of this. Does anyone know what I might be thinking of?

[chewbacha]

They are just very very slow. It does happen but the turnover is not fast and certainly not every 7 years.

[mattkrause]

It’s been very hotly debated for ages.

At the moment, the consensus seems to be that some neurons[*] are occasionally born in adulthood (e.g., in the hippocampus), but there’s a lot less agreement on why or if this matters at all. It could be the remnants of a prenatal process or a neat method for providing “pointers” into memories.

* In the brain itself. It is widely agreed that olfactory sensory neurons turn over every month or two, but they almost have to because they’re exposed to all sorts of junk in the air and wouldn’t survive a lot longer anyway.

[joshuaturner]

ah man I really wanted to be a new person

[malux85]

Then just believe it,

Abstract thing A you can never measure gives you joy and renewal

Abstract thing B you can never measure holds you back and limits you

The practical difference is zero or near zero, so go and be joyful and happy!

[scoofy]

It doesn’t matter whether the cells actually change. The persistence of the self, and even consciousness itself, are very possibly an illusion.

[jstanley]

Consciousness is the only thing that can not possibly be an illusion.

Whenever this comes up I have to wonder if half the people are secretly p-zombies and actually genuinely aren't sure whether consciousness is an illusion because they've never experienced it? I know that's not a very charitable take but I just can't see how any conscious being could imagine that consciousness could be an illusion!

Consciousness isn't the illusion, consciousness is the audience!

[pcthrowaway]

The person above meant "the persistence of consciousness"

Yes, we are conscious (or at least I am, I'm assuming y'all are too).

But consciousness isn't static. My consciousness today is not my consciousness of 5 years ago.

[sage92]

Begs the question: by what metric are you using to track the change/staticity?

I don’t see how one can concretely come to the conclusion of whether it changes or stays the same, when the presence of consciousness itself is a prerequisite of making that very claim

[pcthrowaway]

Well if you believe there's something magical about consciousness I could see why you'd believe the same person's consciousness at different points in time is the same consciousness.

If you believe consciousness is a function of sentience and self-awareness, and presumably that AI can one day be conscious (not saying it is right now), then I don't see how you can believe consciousness is persistent.

If the AI is copied/moved to a different server, is it the same consciousness? Or in Star Trek when you get beamed up are you the same consciousness?

[jhanschoo]

The me who is engrossed in a conversation with a peer over dinner at night focusing on the topic at hand surely is a different consciousness as the me fighting to stay awake just after lunch. They think and emotionally experience very different things.

[richardw]

People run on autopilot unless we put in effort to focus on the current moment. Almost everyone demonstrates bad habits that show how little conscious awareness and control we have. LLM’s can replicate a lot of our activities, so the realm of “consciousness” is in the things that the AI can’t do by simply repackaging and regurgitating content back at us. What we can claim as conscious special sauce has grown smaller over the last 15 years.

Argument 2:

Could we design a machine that is absolutely sure it’s conscious, but is not? If so, what differentiates us from it? Open question, I’m not sure. But I’d be surprised if we can be permanently sure.

[bee_rider]

Argument 2 seems more like a thought-experiment or a question than an argument. (Unless maybe I missed the point?)

Anyway, isn’t a machine that “is absolutely sure” (of anything at all) having subjective experience (I think is the word, not a brainologist) by definition anyway?

We could clearly design a machine that asserts that it is self aware very strenuously

    printf(“I *am* experiencing existence!”); 

But whether or not it actually sure of anything or experiencing at all is the question in the first place.

[richardw]

How do you know you’re not an automaton that thinks it’s conscious?

Not feel. Not think. Not have a strong vibe. Proof.

I don’t have to prove anything here, because I’m not the one making an assertion. My thought experiment demonstrates a situation where an entity thinks it’s conscious but isn’t. Humans think we’re conscious but can’t prove it.

[deepsun]

"Blindsight" by Peter Watts is exactly about that.

[k__]

"The case against reality" is also about that.

But as far as I know, not many scientists think this is a reasonable idea.

[scoofy]

Ultimately it doesn’t matter if it’s reasonable. If it were true, life would be absurd. So, philosophically, we can assume it’s untrue because the alternative means being wrong about it doesn’t matter.

[scoofy]

> Consciousness is the only thing that can not possibly be an illusion.

It can be. Suppose consciousness is a series of infinitesimal snapshots, where existence flickers for a moment and then disappears, with a new existence birthed in the next moment. Like a motion picture, at each moment we do not have a sensible version of consciousness, merely a burst of sensation, but in aggregate, as a film, consciousness springs from nothing.

[Barrin92]

> as a film, consciousness springs from nothing.

But it doesn't. Because the film depends on the screen and the projector. This was one of Kant's central points, although he used the fancy term "transcendental unity of apperception". To even experience a set of images as disjointed, to see individual parts as relating to each other there has to be a unified experience judging them as disjointed against, the "thinking I". Without the observer already implicit in the thought experiment about images constituting a film, there is no "film" because nothing in it would have the ability to even conceive of itself as such. Hindus have a very elegant term for this "witness-consciousness" (Atman), importantly like in Kant distinct from ego and mind, not experience but a formal condition for experience. David Bentley Hart also has a great section about this in his recent book:

"Every composite thing, he acknowledges, is an aggregate of several other things, and all its actions are aggregations of diverse actions and accident. [...] If it’s the composite thing that’s doing the thinking, then each part of the composite possesses only a part of the thought, and only in the aggregate is there a complete thought—but then who or what is having that thought? Where does that thought as a unity occur? Can it be just another part of the brain, with its own diverse parts and its own necessary inner coordinating facility? But then that too is made up of partially competent ..."

[Turskarama]

That's just an implementation detail, in aggregate the result is still consciousness. It's like saying animation isn't real because it's just a sequence of still images.

[scoofy]

The implementation matters.

[wild_egg]

Very similar to how LLMs work but at much higher frequency

[liamwire]

we’re all just CI/CD pipelines

[wat10000]

I agree. It has a great parallel to the debate over mental imagery. There was a big debate over whether it’s real, with one group saying of course it’s real, and the other saying it’s obviously just a metaphor. Turns out some people can visualize stuff and some can’t. Maybe some people are conscious and some aren’t. It would explain why so many people argue weird things about consciousness.

[satisfice]

Consciousness is a phenomenon, but not an illusion. An illusion is something that seems to be there, yet is not. But consciousness is a self-evident experience.

However, there are gradiations of consciousness. The experience we have on the edge of sleep is qualitatively different than the experience even five seconds after waking up to a cat attack in the middle of the night (I have experienced that).

[sage92]

You’ve stated this so matter of factly that I imagine you have knowledge that somehow has alluded most people.

You mention gradients, which implies you can measure the delta/change of conscious, which implies you have a solid working definition, AND a static still point that does not change which this “consciousness” gradually changes.

From my perspective, which is first person pov, if I can detect changes in my “consciousness”, then where am I looking from to _notice_ this change? Is consciousness not the requirement of change detection?

[satisfice]

When I say consciousness is self-evident, I get there by asking myself what it is like to be me.

Whatever consciousness is, it seems vanishingly unlikely that the philosophers talking about it for thousands of years are not talking about this experience I have of being “here now” looking out of my eyes with a constant shower of sensations and interpretations coursing over and by me.

I am not my fingers or hair or forehead in the same vital way that I am this nexus of awareness situated right behind my eyes. But when I am asleep some parts of that awareness are gone. When I am knocked out (by head injury or anesthesia) I so little awareness that I seem to have time traveled when I wake up. (my heart operation seemed to take about one second, and then I teleported to the recovery room).

Sometimes I am very alert, sometimes I am drifting and blinking out. Of course there a gradations of consciousness. Try listening to a book while you are going to sleep.

[bl0rg]

A consciousness without memory (if that's even a possibility) would never notice any change.

[daxfohl]

A body's atoms do completely recycle every 5-7 years though. 98 percent are recycled annually. Weird.

[darkr]

Incorrect

[daxfohl]

I thought so too, but it seems reasonable considering we're 70% water, much of it flowing and actively taking stuff out and around. Plus cells are apparently way more dynamic than is typically conveyed in high school bio (I think there was a quantamagazine article a while ago). So it's perhaps surprising that a body's atoms aren't fully recycled even faster than that.

[gus_massa]

IANAMD. IANAB. Let's guess anyway:

The Ca in bones is probably renewed very slowly. C H O N very fast, in particular water. Na, K and Cl are very soluble and also get renew very fast. Some rare elements like I are probably reused a lot and renewed very slowly. I'm not sure about P, my hand waving is confused. Assuming a burger per day, we ate our weight in meat every few years, but I'm not sure if all the Fe is absorved in and exchanged for the internal one.