Nathan M. Thornhill is a complexity science researcher working in information theory, pattern persistence, AI, and neuroscience. His work circles one deceptively simple question: what separates the systems that persist from the ones that dissolve? His Existence Threshold framework attacks it through measurable information dynamics: integration, differentiation, and the balance between them.
Early work found the numbers. A persistence criterion sorted ten cellular automata without a miss, and crossing a dimensional boundary cost roughly 86% of a pattern's information, measured over 1,500 patterns and again in GPT-2 and Gemma-2. That figure is a measurement at its stated parameters, not a constant of nature. The dynamic extension separates a conscious brain from an unconscious one at AUC 0.91 across 136,394 EEG recordings, convergent with a simpler spectral baseline on the same task.
His most recent work turns the framework on itself, and on the field. A single substrate-neutral scalar of the kind routinely proposed as a sufficiency index for consciousness is, he shows, content-blind by construction: a photograph, white noise, and the word "TRUE" can carry an identical score. The Recursive Existence Threshold locates what that number throws away. Across three substrates (a transformer, the anaesthetized brain, and sleep), the information that tells one state from another lives not in any scalar but in multiply-realizable relational structure. The conclusion is sharp and, he argues, unavoidable: a sufficiency predicate for a mind cannot be a single global number.
Seven preprints, four U.S. provisional patent applications, one framework, collected in Foundations of the Existence Threshold paperback and ebook. He is a student member of the Association for the Scientific Study of Consciousness (ASSC). Thornhill is entirely self-taught; his prior career spans healthcare, from nursing assistant through nursing-home administration and ICU admissions. He built CiteStamp, runs a technology consultancy in Fort Wayne, Indiana, and when he isn't researching he's playing guitar, gardening, or spending time with his wife and daughter.
