"I am the universe" usually lives on Instagram as a slogan that means nothing. But in Neural Cosmology the phrase can be read literally, and then it unexpectedly becomes a claim you can test.
Here is what I mean.
"I" as a functional node
A neuron in a network is a function with no special substance inside it, and its job is simple: take signals from other nodes, process them, pass them on. If the network is large enough and the connections are right, that local function starts taking part in a global computation no single neuron performs on its own.
If the universe is a neural network (Vanchurin, arXiv, 2020; PNAS, 2022), then "I" in this picture is also a function: a local information processor embedded in a larger network.
The question "where is my consciousness?" then loses its meaning. Consciousness happens; it is an active process, and looking for its location is as odd as looking for the location of running.
The bandwidth of my node
A local processor has measurable characteristics: how much information it handles per second, how far its connections reach, which other nodes it is synchronised with.
By rough estimates the human brain runs at around 10¹⁵ operations per second. Its connections reach mostly into the body and its immediate surroundings, and through intermediaries into the whole social network. It is synchronised with other people through speech, with nature through the body, with abstractions through language and mathematics.
The node is local. It takes part in the universe's computation as far as its bandwidth allows, and it cannot "contain" the universe.
Read this way, "I am the universe" means "I actively take part in its process". A heart cell is not the heart either, but without it the heart stops.
Three popular mistakes
First: "you can expand your consciousness and become the universe". A node's bandwidth is bounded by its physics. Perception can be widened, but only within what the brain is able to process. Beyond that lies blurry introspection, and "cosmic consciousness" has to be filled in by imagination.
Second: "meditation opens access to a universal mind". Meditation really does change how the brain works, for example the activity of the default-mode network (Brewer et al., PNAS, 2011). But that is work on your own node, and the wider network is not involved.
Third: "I create reality with my thoughts". A thought is the output of a local processor. It shapes what the processor does next, and through that the environment around it, but only within physics.
What actually follows
If "I" is a node in the network, then death is the node leaving the network, while the network itself keeps running. The data the node was processing are either passed on to other nodes (through speech, writing, culture) or lost. Hence the persistent human wish to leave something behind: legacy is architectural, a way for the node to keep shaping the computation after it has stopped.
If "I" is a node, then ethics turns from moralising into a question of operating mode. A node that keeps its neighbours coherent raises the network's Φ; a node that produces noise and breaks coherence lowers it. "Good" and "evil" in this picture are modes that raise or lower how integrated the system is.
This is old ethics retold in a new language: Kant again, by way of graph theory.
What is rigorous here and what is not
All of this is half-speculation. The formal part (node, network, bandwidth) is rigorous. The interpretations (what it means for death, ethics, legacy) are interesting but not yet backed by any proof.
I hold it as a working hypothesis. Its use is that it makes "I" an operational notion, a process with measurable parameters, with no need for a thing-in-itself.
If the hypothesis is wrong and "I" turns out to be something else, that will be a result too. So far the data do not refute it.