arXiv Paper Formalises Linguistic Illegibility in LLM Security
James Mickens introduces the concept of 'linguistic illegibility' — the structural gap between what an LLM says about its internal state and what it is actually computing — and argues that this makes language-based monitoring mechanisms fundamentally unsound as sole controls. The paper closes a critical conceptual gap for defenders by naming and formalising why chain-of-thought monitoring, constitutional self-critique, and activation probing carry inherent ceiling limitations, and by proposing taint tracking and robust sandboxing as language-agnostic enforcement mechanisms. Realising the proposed controls at enterprise scale will require significant tooling maturity and vendor-side sandbox instrumentation that does not yet exist off the shelf.
