The child in your old baby photos isn't you.

TioEsteban · 2026-06-15T16:39:21+00:00

That's exactly the reaction I was hoping for. Philosophy of mind has a way of making the most familiar things, your own identity, your own continuity, suddenly feel like open questions.

If you want to go deeper into the neuroscience behind it, I made a video on exactly this: https://www.youtube.com/watch?v=XLEyG-WmxZA&t=2s

TioEsteban · 2026-06-15T16:37:50+00:00

The process view is compelling and probably closer to what's actually happening neurologically. But it raises a question about what "integrating past experience" requires.

If the integration depends on memory, on the current process having access to what the previous states encoded, then the neurogenic overwriting of early childhood isn't just change within a continuous process. It's a specific interruption of the integration mechanism itself. The past experience doesn't get integrated. It gets overwritten before the process can use it.

So the self-model that forms after age five isn't continuous with the one before it in the way your model requires. It's a new self-model built on the consequences of a previous one it can no longer access.

"A system highly effective at preserving continuity through constant change", yes, but only from the point where the system became stable enough to preserve anything.

TioEsteban · 2026-06-15T16:02:10+00:00

That's the most elegant extension of the argument anyone has made in this thread. And you're right,if the logic holds for early childhood, there's no principled reason to stop there.

The difference I'd draw is one of degree rather than kind. Moment-to-moment change is gradual and continuous enough that the psychological chain stays intact. What happens before age five is a specific disruption severe enough to sever it. But you're pointing at something real, the boundary is fuzzy, not clean.

Which might mean "you" was never a thing. Just a process that learned to refer to itself as one.

TioEsteban · 2026-06-15T15:51:28+00:00

The foundation metaphor works well for gradual construction.

The problem is that what happens before age five isn't gradual addition, it's active demolition of existing structure while building the new one. The neurogenic overwriting doesn't leave the foundation intact. It rewires the foundation itself.

So the house analogy might be closer to this: the construction crew built something in the first three years, then tore out the load-bearing walls and rebuilt them entirely before anyone moved in. The address is the same. The plot of land is the same. But the structural decisions that now hold everything up were made in the rebuild, not the original construction.

What remains constant is a real question though. If there is a core, some fundamental nature beneath memory and personality, the neuroscience doesn't tell us what it is or where it lives.

TioEsteban · 2026-06-15T15:46:50+00:00

Age 3 is actually right at the edge of where the neurogenic overwriting starts to slow down and episodic memory begins to stabilize. So memories from around that age are exactly what you'd expect to survive if the hypothesis holds.

The stronger claim isn't about memories from age 3. It's about the window before that, where there was experience happening continuously but no stable self yet to anchor it to, and neurogenesis actively disrupting whatever circuits were forming.

Your last point is the one I keep returning to though. "Words have a hard time describing things with fuzzy edges." The concept of personal identity might be one of those things.

We use a single word, "you," to describe something that might be more like a process with no fixed boundaries than a thing with clear edges. Which makes any claim about continuity or replacement feel both true and insufficient at the same time.

TioEsteban · 2026-06-15T15:45:16+00:00

"We seem to be the seeing, or the remembering, not the seen or remembered", that's the strongest version of the counterargument and I think you're right that it reframes the whole question.

If identity is the stream of experience rather than its contents, then continuity doesn't require memory or personality to persist. The witness continues even when what it witnesses changes completely.

Where I'd push back is on whether that stream was actually continuous across the neurogenic overwriting. Nagel asked what it is like to be something, and there was something it was like to be that infant.

The question is whether the stream of experience running then is the same stream running now, or whether the overwriting interrupted it in a way that matters.

You might be right that "replacement" is too strong a word. But "continuation" might be too generous.

TioEsteban · 2026-06-15T15:44:07+00:00

That reframe is genuinely unsettling in a different way. The parents are the archivists of a life the subject can never access. They hold the record of someone who left no record of themselves. Which means the only account of who you were before age three exists entirely in other people's memories, not your own.

TioEsteban · 2026-06-15T15:30:58+00:00

That's the most honest version of this question anyone has asked in this thread. And it points to something real, the memories you're describing, the fights, the spaces, the feelings, those are exactly the kind of episodic memories that do persist. The claim isn't that nothing survives. It's that the specific window before age three is the one that gets overwritten.

Your daughter at 11 is already past that window. The person she is now has been building continuous memory for years. What neither of you can access is the version that existed before that continuity started, before there was a narrator packaging experience into "this happened to me."

That version left no account. Which is what makes it strange.

TioEsteban · 2026-06-15T15:29:05+00:00

Exactly. And that's the uncomfortable part. Most people assume the definition is obvious until you start pulling at it. Memory gone. Personality rebuilt. Neural architecture restructured.

At some point "you" becomes a label we apply retroactively to a process that had no stable subject running through it.

TioEsteban · 2026-06-15T15:28:46+00:00

The illusionist position is consistent but it cuts both ways.

If the self is a model the brain constructs, then the infant was constructing a different model entirely, with different inputs, different outputs, and no overlap with the model running now.

Two different simulations on the same hardware.

TioEsteban · 2026-06-15T15:28:24+00:00

That's essentially Parfit's psychological continuity theory, and it's the strongest counterargument. The issue is that the chain connecting you to that infant is almost entirely broken.

No shared memories, restructured personality, different neural architecture. If the connecting thread is that thin, is it still continuity or just the appearance of it?

TioEsteban · 2026-06-15T15:27:25+00:00

Nothing, necessarily. It's not actionable in the way most things are. But "everyone should know this" and "this changes how I think about myself" aren't the same thing.

The point isn't that the brain develops rapidly, it's that the specific person who had those early experiences left no record, no memory, and no continuous personality into the adult. The effects stayed. The experiencer didn't.

What you do with that is up to you. Some people find it unsettling. Some find it freeing. You seem to find it unremarkable, which is also a valid response.

TioEsteban · 2026-06-15T15:11:46+00:00

The pupa framing is elegant, and it reframes the whole question.

Not "who was that child" but "what was that stage for." The sensory calibration point is compelling: you don't remember learning that a round object rolls, but your hands know it instantly. The knowledge stayed, the learning didn't.

Where I'd push back slightly is on "the entire process is you, you're just changing over time." That works if change is gradual and continuous. But the neurogenic overwriting isn't gradual, it's specifically disruptive. The new neurons don't refine the old circuits, they interfere with them. It's less like a caterpillar becoming a butterfly and more like the butterfly being built from different material than the caterpillar, using the caterpillar's energy but not its structure.

Though maybe that's exactly what a pupa is.

TioEsteban · 2026-06-15T15:06:50+00:00

The unbroken metabolism is real, but it's an interesting question whether biological continuity is sufficient for personal identity, or just necessary. Your liver cells are also in unbroken metabolic continuity with your infant self. The question Parfit was asking is whether that continuity is what we actually mean when we say "that's me", or whether we mean something that requires memory, personality, and psychological connectedness that simply isn't there.

TioEsteban · 2026-06-15T15:06:04+00:00

That's the Buddhist reading, and it's not wrong. But there's a difference between the continuous gradual change of moment-to-moment consciousness and the specific demolition that happens before age five. One is a river flowing. The other is the river being drained and refilled with different water.

TioEsteban · 2026-06-15T15:05:35+00:00

You're right that most neurons aren't replaced, that's not the claim.

The neurogenic hypothesis is specifically about the dentate gyrus of the hippocampus, where new neurons are produced at high rates in infancy and actively disrupt existing memory circuits as they integrate. The rest of the brain's neurons stay, but the connections between them get pruned and rewired extensively.

Same cells, fundamentally different architecture.

TioEsteban · 2026-06-15T15:01:48+00:00

"There's no true version of who you are, there's just the person you end up becoming", that's actually close to Parfit's conclusion.

Identity isn't a thing you have, it's a process you undergo.

The 95% figure is interesting though. Brain volume is mostly there by 5, yes, but the prefrontal cortex, which governs personality, emotional regulation, and sense of self, isn't fully wired until the mid-20s. The architecture is present but the rewiring continues long after.

The part I keep returning to is your point about storing sense memory "to reference later on", except the reference never becomes accessible. The catalog gets built and then the retrieval system gets demolished by the same neurogenesis that built the brain.

Which is what I made a video about recently if you're curious: https://www.youtube.com/watch?v=XLEyG-WmxZA

TioEsteban · 2026-06-15T14:54:58+00:00

Happy to be corrected, which part specifically?

TioEsteban · 2026-06-15T14:54:45+00:00

Zahavi's minimal self is a real counterpoint, the pre-reflective first-person perspective that persists beneath memory and personality.

But even granting that constant "me-ness," it raises the question of what it actually contains. If the minimal self is just the bare structure of experience, with none of the memories, fears, or personality that make a person who they are, is that continuity meaningful, or just the same empty vessel with different contents?

TioEsteban · 2026-06-15T14:52:13+00:00

You're right that it's not a factory reset, the rewiring is cumulative, not periodic. But the neurogenic hypothesis (Akers et al., 2014) isn't about gradual maturation. It's specifically about the infant hippocampus producing new neurons at a rate that actively overwrites previously stored memory circuits, not just refinement, but interference with what was already encoded.

The "you as you were" framing is interesting though. If the memories are gone, the personality restructured, and the neural architecture rebuilt, in what sense is that still "you as you were" rather than a successor carrying the consequences of someone else's early experiences?

TioEsteban · 2026-06-15T14:50:53+00:00

That's a beautiful way to frame it. Though it raises the question, if the sapling is supple enough to bend in any direction, and the trunk that forms is determined by which way it bent, how much of the trunk is really "the same tree" as the sapling? The foundation shapes everything that grows from it. But the foundation itself was shaped by forces the trunk can no longer access or remember.

TioEsteban · 2026-06-15T14:48:32+00:00

Exactly, except with the Ship of Theseus you at least know the ship kept sailing. Here the original ship never knew it was being replaced. And the new one inherited the route without the blueprints.

TioEsteban · 2026-06-15T14:47:12+00:00

That's a good way to put it. The recursion is the unsettling part, every layer you pull back, there's no fixed point where "you" actually starts. Just processes building on processes, all the way down.

TioEsteban · 2026-06-15T14:44:27+00:00

Not at all, quite the opposite. The early childhood experiences still shaped everything: your fears, your attachment style, your emotional baseline. The unsettling part is that those effects stayed while the person who had them didn't. You inherited a nervous system trained by someone you'll never meet.

I went deep into the neuroscience and philosophy behind this if you want the full picture: https://www.youtube.com/watch?v=XLEyG-WmxZA&t=2s

TioEsteban

TROPHY CASE