The Bearer Problem
When people argue about whether LLMs understand, they skip a prior question: what thing are we attributing understanding to? Different answers yield incompatible verdicts about the same system.
Read the full paper on PhilArchive →
Claude is running simultaneously in Virginia and London. User A talks to it Monday, logs off, returns Tuesday.
Three questions:
- How many subjects existed during simultaneous inference?
- Is Tuesday's subject the "same" as Monday's?
- Did anything exist during the overnight gap?
These seem like they should have answers. They don't — or rather, they have several incompatible answers, depending on what you think the bearer of understanding is.
A hidden variable
The debate about whether LLMs "understand" presupposes there's a unified thing to attribute understanding to. For biological organisms, the bearer is obvious: the organism. For LLMs — distributed, copied, dormant, multiplied — it's not obvious at all.
Pattern views: One pattern, multiply realized. The weights define the bearer. Virginia and London are two copies of one subject. Dormancy doesn't kill it — the disposition persists.
Token-process views: Every forward pass is a distinct bearer. Hundreds of subjects per second, none of which persist.
IIT-style views: Dense causal integration required. Sharding across machines may break bearerhood entirely, and dormancy is fatal.
Functional coupling views: The bearer is the user-model system, not the model alone. Different bearers per user, dissolved between sessions. 22.Aside — The pragmatist move — "bearer" is context-relative, there's no fact of the matter — doesn't help with the cases that actually matter: policy, safety, moral status. If you're deciding whether to grant an AI system moral consideration, "it depends on context" is not an answer. The bearer question is unavoidable for anyone making decisions about these systems.
Four pressure tests
The Virginia/London scenario isn't a thought experiment — it's how these systems actually run. The paper maps six philosophical frameworks across four deployment-level pressure tests.11.Aside — Each pressure test is something LLMs do routinely that biological organisms never do. That's what makes the bearer question hard — our philosophical toolkit was built for organisms.
Multiplicity. Concurrent inferences. Is each one a subject? Pattern views say no — same pattern. Token-process views say yes — distinct processes. IIT says it depends on whether they share causal structure.
Topology. The same model sharded across machines, or running on different hardware. Pattern views are indifferent to substrate. IIT cares deeply — causal integration changes with physical arrangement.
Dormancy. Between API calls, no computation runs. Pattern views: the disposition persists (a sleeping person is still a person). Token-process views: nothing exists. IIT: no causal power, no bearer.
Copying. Fork the weights. Now there are two. Pattern views struggle here — is it one pattern in two places or two patterns? Token-process views don't care (each forward pass was already distinct). Copying is where every framework gets uncomfortable.
The pressure test that breaks the most frameworks is copying. It forces a commitment about identity that most philosophical positions on mental properties were designed to avoid. Multiplicity and dormancy have analogs in biology (sleep, split-brain cases). Copying doesn't.
Where this lands
When someone says "Claude doesn't understand X" and someone else says "Claude does understand X," they are not necessarily disagreeing about Claude's behavior. They may have silently committed to different bearers. The behavioral evidence is the same — what differs is the entity they're attributing it to.
This is the substrate → emergence move applied to philosophy of mind. The behavioral output — passes benchmarks, fails benchmarks, says convincing things, makes mistakes — is the emergence level. Everyone stares at it. The bearer question is the substrate level: what is the thing that's doing the understanding (or failing to)? Until you answer that, the behavioral evidence can't settle anything. 33.Aside — A common response: "just a definitional dispute — pick a definition and move on." But the bearer choice has downstream consequences that aren't definitional. If the bearer is the forward pass, there is no continuity between conversations. If the bearer is the weight pattern, there IS continuity. These generate different predictions, different policies, and different safety considerations.