As their limousine nears Bubeneč and the U.S. ambassadorial residence, Robert Langdon presses Katherine Solomon to continue explaining her theory that humans are surrounded by reality their brains normally cannot perceive. Katherine says her insight began while comparing epileptics’ postictal “bliss” reports with near-death experiences, which share themes of disembodiment, universal connection, and profound peace.

Katherine describes an experiment with a terminally ill retired neurologist who agreed to die while being monitored in a real-time magnetic resonance spectroscopy scanner. Katherine observes expected rises in neurotransmitters like adrenaline and endorphins, but the crucial surprise is that GABA does not rise to “filter” the dying experience; instead, GABA drops sharply toward zero, implying the brain’s normal perceptual filters fall away as death approaches. Katherine argues this would allow consciousness to take in an unblocked “full spectrum” of reality, explaining why near-death accounts report all-knowing bliss.

Katherine adds that in the final minute before the patient’s heart stops, the brain shows extreme high-frequency oscillations including gamma waves associated with intense memory retrieval. Katherine interprets this as evidence for “full life recall,” aligning with religious motifs of reviewing one’s life at death. She believes the dying process provides a preview of expanded perception, even though the brain ultimately ceases functioning.

When Langdon asks whether death is the end, Katherine proposes that if consciousness originates outside the brain—as noetic research suggests—then death may be consciousness leaving the physical body and reintegrating into a larger whole: the body is no longer needed to “receive” the signal because “you are the signal.” Langdon recognizes the transformative implications if Katherine is right that humans possess the hardware for deeper perception but are chemically prevented from using it.

To answer Langdon’s objection that dying would make the truth impossible to share, Katherine argues death is not the only route to lowered filters. She cites moments of genius and revelation in science and religion, then explains that psychedelics similarly reduce GABA via the brain’s default mode network, meaning users may be perceiving more reality rather than hallucinating. Katherine frames this as potentially world-changing: lowering filters could foster unity, compassion, and a broader understanding necessary for humanity’s survival—though it still does not explain why anyone is trying to destroy her manuscript. The limo reaches the residence’s iron gate, is waved through by a Marine, and Langdon worries they may be entering either sanctuary or trap.