Who Wakes Up If You Don’t?

Before we talk about freezing brains, let’s talk about who’s in there.

“...when I go to sleep to have the uploading procedure, will it be me that wakes up inside the computer?” (—Michael Cerullo, Uploading and Branching Identity (2014))

A banger of a question, really.

It gives me the same sensation I had at 5 years old when I realized I *will* expire one day, and when I do: where will *I* be after that?

It’s the same sensation I had in “Rick Potion #9” (S01E06) when Rick & Morty…okay, no spoilers, read the footnote only if you HAVE watched.¹ This episode launched me into a three-week existential crisis. I was not okay! I couldn’t stop thinking about timelines, memory, selfhood, continuity. And loosely, it cracked something open about identity: whether a version of me could go on without me.

Well, can it?

I was talking about all this out loud at a gathering when someone said: “You need to meet Natalie Coles.” I didn’t know then that she was a pioneering supercentenarian researcher. I just figured she was someone who would understand my current spiral. This chance encounter in 2022 would kick off my entire Longevity Biotech Fellowship journey and Cryo obsession - but more on that later.

Somewhere between talking about life extension and metaphysics, she casually mentioned that her late husband’s brain is cryopreserved². That moment with Natalie didn’t just make cryopreservation real.

It made the question louder in my head: what are we saving, exactly, and who wakes up afterward?

The thing about cryopreservation is that it feels like it solves something. But it only raises a new question: if you wake up again, is it still you? And if there are two versions of you, even for a microsecond, which one gets to keep the thread?

There are different bets, different philosophies. Some go for full-body suspension³, like hitting pause on the whole package. Others say, nah, just the brain, because that’s where the good stuff lives. But here’s the kicker: are we saving you—your identity—or just the brain’s wiring?⁴ Can memories survive the deep freeze? Or are we just scanning a pattern and hoping to reboot it later, uploading a version of you⁵ and calling it close enough?

To me, this is the most boggling thought and question of all: there is a difference between technical survival and felt continuity. If your brain gains function again, with or without you in it, or if there is no more physical brain but an upload of you…is it really you?

Now I am somewhere between philosophy and panic.

Alright, so what does it feel like to continue?

Meet Dr. Andy McKenzie, a research scientist at Apex Neuroscience. He’s perfecting ways to preserve the connectome, your brain’s memory web. With a neuroscience PhD and computational chops, Dr. McKenzie digs into brain data to nail preservation techniques like fluid fixes and cryonics. His goal? Boost brain banking for disorder research and push cryonics toward reality. He also writes Neurobiology Notes. At the end of our lovely Zoom chat, he sends me some recommended reading that I will now share with you.

📚 Michael Cerullo’s “Uploading and Branching Identity”
The Big Idea: A copied mind doesn’t erase the original…it branches it. If two versions of you wake up, they’re both you, consciousness. Just on different tracks now. Fork your mind, and suddenly there are two “you”s on different timelines. Both real, but only one gets your heartbeat.

Mind Benders:

• Cerullo leans on split-brain cases: epilepsy surgeries that sever the corpus callosum, to show one brain can literally act like two “yous.”⁶ Each hemisphere still holds your memories, but they start running off on their own. His point: if biology can fork identity, then a perfect upload could do the same.

• Cerullo points out that our brain perceives events as simultaneous if they happen within about 40 ms⁷ of each other (thanks to Efron 1970; Ruhnau 1995; Breitmeyer and Ogden 2000; Pockett 2003; Dainton 2014).⁸ He uses this to argue that a branch in identity could occur without you ever feeling the split.

Random, OCD Side Quest:

This is dumb as hell, but I used to obsess over this exact forking⁹ problem every time I accidentally downloaded a file twice. Always in a damn hurry. Two files. I edit one. The other still there, lingering, the voice in my head is like “Delete that right now!” but I never did and when I come back on task, I forget which one is edited, even though “the spare” one is always saved with the dreaded “1” at the end. Two different journeys for these OG files, they are not the same. They’ve FORKED! Btw, I now I always go back and choose the first download to edit. This may say something about where my ideology skews in all of this.

📚 Kenneth Hayworth’s “Killed by Bad Philosophy”
The Big idea: Consciousness isn’t mystical, it’s physical! Hayworth argues that your identity lives in your brain’s structure. If we can preserve that structure well enough, we can preserve you. The real danger? Letting outdated philosophy stop us from even trying. This is a call-to-action piece if I’ve ever read one.

“They will say we were killed by our bad philosophy.”
(Hayworth, in what might be the most haunting pull-quote of the whole cryo canon)

Mind Benders:

• Your “self” is a neural map: patterns of synapses, firing rates, and memory traces. Save that map with precision, and Hayworth says you survive. No soul required.

• He calls the “copy problem” (“but is it really me?”) a distraction. If the structure’s right, the outcome is you. Don’t overthink it.

• To him, destructive uploading¹⁰ (meaning, scanning and then destroying the original brain) is acceptable, IF if the reconstruction maintains continuity. What’s riskier? Doing nothing and dying for sure.

Now, before I could even finish my identity threads and neural maps crash out, long-time builder in longevity and LBF co-head honcho, Nathan Cheng, sends me a paper with a simple but wild premise:

“Death is an engineering problem.”

It introduced me to Synconetics, a new discipline that treats consciousness like a process you can sustain, transfer, or preserve…if you’re careful enough.

📚 Daniel Burger, Izumi Handa, Gabriel Cunha, and Masataka Watanabe’s
“Death Is an Engineering Problem”
Big idea: Death isn’t fate. It’s a system failure. This paper introduces a new field called Synconetics, a discipline that treats the continuity of consciousness as something we can preserve through engineering. Think: not uploading, not magic, but thermodynamics, substrates, and process continuity.

“Death marks the irreversible termination of the four-dimensional process-world-line.” Translation: If you can keep the brain’s core activity going, or transfer it without interruption, you might just keep you.

Mind benders:

• Synconetics introduces Processual Continuity¹¹, which is a fancy way of saying you are not just your brain, but the ongoing process your brain runs. Interrupt that process, and poof, you're gone. Preserve it, and you might stick around.

• Instead of copying your brain (which might kill the original), Synconetics favors non-destructive transitions, or slowly swapping in new parts (like biohybrid grafts or synthetic hemispheres) while keeping the lights on.

• The ultimate goal? Build consciousness-supporting substrates more resilient than biology. Bodies break. Circuits can be backed up.

This is the part where you start to wonder: is immortality going to feel less like a miracle and more like maintenance? 👀

These three perspectives, Cerullo, Hayworth, and the newly minted Synconetics, each offer a different answer to the same question:

What’s worth preserving? And how do we keep it going?

I don’t know who’s right yet, and to be clear, these readings aren’t the whole picture. Just a slice of the thinking out there and what I’m reading right now. You’d think my first-download-always-wins tangent would make my bias obvious, but Synconetics has me in a chokehold, at least in this very moment we call now (all 40 milliseconds of it). Still, I’ve got a lot more reading to do before I commit to anything.

Before we got into the physical stuff of Cryo: the liquid nitrogen, the protocols, the logistics of freezing a brain, I wanted to start here to ask the real question first:

What makes you you? And what are we actually trying to save?

Next time: Cryopets, cold storage (yes, literal), and what it takes to press pause on a person.

Bring snacks.

1. In this episode, Rick and Morty abandon their timeline after irreversibly altering it, leaving behind versions of themselves and assuming the lives of alternate counterparts. It’s one of the show’s earliest and most unnerving takes on identity, continuity, and consequence (and bury themselves).

2. Cryonics is the low-temperature preservation of humans (or animals) after legal death, with the hope that future technology can restore them to life and health.

3. A preservation approach where the entire body is stored at ultra-low temperatures (not just the brain) on the chance that future medicine might be able to repair and revive everything, not just the head.

4. I’ve been using em dashes longer than you’ve been alive.

5. Uploading: The hypothetical process of scanning your brain’s structure and recreating it in software, essentially turning “you” into a digital consciousness. The big question? Whether the upload feels like you…or just acts like you.

6. The corpus callosum is the thick bundle of nerves that connects the left and right sides of your brain. In split-brain surgeries (sometimes done to treat epilepsy), this bridge is cut—leading to wild cases where each hemisphere acts on its own, raising the question: if your brain can split, can your “you” split too? More here: https://my.clevelandclinic.org/health/body/corpus-callosum

7. This refers to psychophysical studies suggesting that the brain perceives two events occurring within 40 milliseconds of each other as simultaneous, affecting how we experience time and continuity.

8. Don’t worry, we will be chatting more about “How long is NOW?”

9. The Good Place lovers, wya

10. A speculative process where a brain is scanned in such high resolution that it’s destroyed in the process, raising ethical questions about whether the upload is you or just a copy.

11. A term from Synconetics that reframes consciousness as a dynamic physical process in space and time, not just the structure of the brain, but its ongoing activity.