What is a cortical stack in Altered Carbon?
Richard K. Morgan’s novel Altered Carbon was first published by Gollancz in the UK in 2002, and its US edition won the Philip K. Dick Award. It opened a trilogy about Takeshi Kovacs, a former elite soldier who is brought back in a new body to investigate a rich man’s death.
Netflix adapted it as a series created by Laeta Kalogridis. Season one arrived in February 2018 with Joel Kinnaman as Kovacs; season two followed in February 2020 with Anthony Mackie in the role. An anime film, Altered Carbon: Resleeved, came out in 2020, and Netflix cancelled the series after two seasons later that year.
The central idea is simple. Almost everyone has a cortical stack at the base of the skull that stores their consciousness. Bodies are called sleeves. If your body dies but your stack survives, your mind can be put into another sleeve. Destroy the stack and you suffer “real death”. The very rich keep remote backups, so they can live for centuries, while most people cannot afford to keep resleeving. Copying one mind into two bodies at once is a serious crime.
Five assumptions behind the stack, checked
A stack only works if several separate things are possible. Here is where each stands in 2026.
| What the story assumes | Status in 2026 |
|---|---|
| A whole mind can be read out of a living brain | No. No method can record the full state of even one living human brain. |
| That mind fits on a small, durable device | No. A single cubic millimetre of human cortex produced about 1.4 petabytes of microscope images. |
| It can be written into a different brain or body | No. There is no known way to “write” memories or personality into neurons. |
| A restored copy is the same person | Unresolved. This is a philosophical question, not an engineering one. |
| Minds can be sent across space as data | No. This depends on all the steps above. |
How close is real brain mapping?
The nearest real science is connectomics: mapping every neuron and connection in a piece of brain. It has made remarkable progress.
- 2024, fruit fly. The FlyWire consortium published in Nature a wiring diagram of a whole adult fly brain: about 140,000 neurons and more than 50 million synapses.
- 2024, human tissue. A team from Harvard and Google described in Science a cubic millimetre of human temporal cortex, with about 57,000 cells and 150 million synapses.
- 2025, mouse. The MICrONS project published in Nature a cubic millimetre of mouse visual cortex: more than 200,000 cells and over 500 million synapses, linked to recordings of how the neurons responded.
For scale, a human brain has roughly 86 billion neurons. These maps were made from preserved tissue cut into ultra-thin slices and imaged, which destroys the sample. They show wiring, not the chemical and electrical activity that makes up a living mind at any moment. Scientists use them to understand how brains work, not to store anyone. Our Transcendence fact check looks at the uploading question in more detail.
What brain implants can and cannot do
Brain-computer interfaces are real and improving, but they work with a tiny fraction of the brain’s signals.
- Speech. In 2024, researchers reported in the New England Journal of Medicine that implanted electrodes let a man with ALS turn attempted speech into text with high accuracy.
- Memory support. A 2018 study in the Journal of Neural Engineering found that carefully timed stimulation of the hippocampus improved performance on memory tests in a small group of epilepsy patients who already had electrodes for medical reasons.
These are medical tools. They help with a specific task, such as moving a cursor or producing words. None of them can read out a person’s memories, values or sense of self, and none can move them anywhere.
Altered Carbon treats the stack as a finished, boring technology. In reality, the hard part is not storage but understanding: science still cannot explain how memories and personality arise from brain activity.
The copy problem the story already knows
The book quietly admits its own puzzle. If a mind is just data, it can be copied, and then which copy is you? That is why double-sleeving is outlawed in the story. Real philosophers have argued about this for centuries, and fiction keeps returning to it, from Ghost in the Shell’s copied “ghosts” to the paid afterlife of Upload.
For a practical reader the useful point is this: even a perfect record of someone is a record. It does not carry their experience forward, and it does not let the original person continue.
What actually exists: AI clones built from data
What people can build today is far more modest than a stack. An AI clone is a language model guided by a person’s own words: their messages, notes or recorded interviews. It can imitate how someone writes and recall facts that appear in those records. It has no access to their brain, no inner experience and no new memories of its own life.
That difference matters. A stack, if it existed, would claim to be the person. An honest AI clone should always present itself as a simulation.
Where Memory Clone fits
Memory Clone is a Windows app, currently in alpha, that builds a private AI simulation from chats you export yourself, such as WhatsApp, Messenger, Instagram or Discord, plus your own notes. It learns writing style separately for each relationship.
- Text only today. It does not use voice notes, photos or video, and it does not clone voices.
- Not a stored mind. Every clone is presented as an AI simulation, not the person. It preserves something of how someone wrote, nothing more.
- Local first. Imported originals and the memory index stay on your PC. Cloud replies start only if you switch on cloud processing for a clone.
- Consent matters. Users must be 18 or older, and cloning a living person requires their permission under our Acceptable Use Policy.
常见问题
Is a cortical stack possible?
Not with any known science. It would require reading, storing and rewriting a complete human mind, and none of those steps can be done today.
Can we upload a brain to a computer in 2026?
No. Researchers can map small pieces of preserved brain tissue and whole insect brains, but these maps do not capture a living mind and cannot be run as a person.
What is resleeving in Altered Carbon?
It is moving a person’s stored consciousness from their stack into a new body, called a sleeve. In the story it lets people survive the death of their body.
Was Altered Carbon cancelled?
Yes. Netflix released two seasons, in 2018 and 2020, plus an anime film in 2020, and then cancelled the series.
Is an AI clone the same as a stored mind?
No. An AI clone imitates patterns in someone’s words. It does not contain their consciousness or experience.
资料来源
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- Altered Carbon (novel by Richard K. Morgan, 2002) (Wikipedia)
- ‘Altered Carbon’ Canceled by Netflix After 2 Seasons (Tim Baysinger, 2020) (TheWrap)
- Altered Carbon (TV series, 2018 to 2020) (Wikipedia)
- Dorkenwald et al., “Neuronal wiring diagram of an adult brain” (Nature, 2024) (Nature)
- Shapson-Coe et al., “A petavoxel fragment of human cerebral cortex reconstructed at nanoscale resolution” (Science, 2024) (Science)
- MICrONS Consortium, “Functional connectomics spanning multiple areas of mouse visual cortex” (Nature, 2025) (Nature)
- Azevedo et al., “Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain” (2009) (Journal of Comparative Neurology)
- Card et al., “An Accurate and Rapidly Calibrating Speech Neuroprosthesis” (NEJM, 2024) (New England Journal of Medicine)
- Hampson et al., “Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall” (2018) (Journal of Neural Engineering)
This article is general information, not medical, legal or financial advice. Memory Clone creates an AI simulation from the material you provide; it is not the person.