Chronological Failure-Point Map: The Extracorporeal Brain as a Design Problem

This paper treats an indefinitely maintained, functioning, extracorporeal human brain as a fixed design goal, without claiming such a goal is achievable. Rather than proposing solutions, it asks a narrower question at each stage: assuming every prior problem has somehow been solved, what new failure mode does that solution expose? Working chronologically from the moment of surgical isolation (vascular cutover, intracranial pressure, artificial CSF) through early cellular stress (ROS accumulation, glial telomere attrition) to century- and millennium-scale problems (synaptic information-storage saturation, somatic carbon-14 decay, epigenetic entropy, thermodynamic limits on information fidelity), the paper maps failure points across eight domains: vascular & systemic isolation, glial & extracellular homeostasis, virtual sensorimotor environment, intracellular & genomic maintenance, epigenetic & structural preservation, biophysical & metabolic buffering, brain-machine memory integration, and continuity-oriented redundancy systems. The goal is not to argue feasibility, but to provide a systematic problem checklist for speculative work in this space.