Computronium
The idea of computronium arises when physical law is treated as a limit on how densely matter can be arranged for information processing, shifting attention from software fantasies to measurable constraints on energy and entropy.
When Norman Margolus and Tommaso Toffoli introduced the term computronium, they established a theoretical boundary: matter configured precisely to process information at the maximum density permitted by physical law. Subsequent developments in theoretical physics have given this concept exact numerical weight. Rolf Landauer defined the absolute thermodynamic energy cost associated with erasing a single bit of information. Jacob Bekenstein formulated the Bekenstein bound, which caps the maximum quantity of information contained within a given physical region of specified mass and radius. Pushing these principles to their physical extreme, Seth Lloyd calculated the computational upper bound of a single kilogram of matter when every internal degree of freedom is recruited for information processing. At stellar dimensions, Robert Bradbury expanded this premise into the Matrioshka brain, conceiving a series of nested Dyson shells designed to capture the total energy output of a star, using the cascading thermodynamic waste heat of each inner sphere to power the computational processes of the outer layers.
Mormon theology raises no objection to the premise that thought runs on matter. “There is no such thing as immaterial matter,” Joseph Smith taught, adding that spirit is “more fine or pure” and discernible only by purer eyes (D&C 131:7-8). Doctrine and Covenants 93:36 identifies glory with intelligence, and intelligence with light and truth. Matter organized to think, on that account, describes creation working as intended.
Earth as a Great Urim and Thummim
The Earth in its sanctified, immortal state is transfigured into a celestial sphere where all truth is manifest.
Doctrine and Covenants 130 supplies the closest scriptural analogue to a planetary computational substrate. The place where God resides is called “a great Urim and Thummim,” and this earth “in its sanctified and immortal state, will be made like unto crystal and will be a Urim and Thummim to the inhabitants who dwell thereon, whereby all things pertaining to an inferior kingdom, or all kingdoms of a lower order, will be manifest to those who dwell on it.” In this divine vista, an entire planetary body will be transformed into a celestialized, crystalline substrate that will act as a medium of revelation for its inhabitants. The text immediately links this macroscopic function to a localized, individualized corollary. Invoking the apocalyptic promise of Revelation 2:17, Joseph Smith explains that each exalted being will receive a "white stone" which will serve as a personal Urim and Thummim whereby "things pertaining to a higher order of kingdoms will be made known." The exalted saint is thus situated between the planetary medium, which mediates knowledge of inferior realms, and the personal stone, which yields access to the ascending orders of the cosmos.
Creatio ex Materia
Doctrine and Covenants 93:29 holds that intelligence was not created and cannot be. Whatever computronium could accomplish, it could not create a person from nothing. Physical substrate can host and magnify intelligence, but it cannot create a spirit body. This principle resists the utilitarian temptation to view thought as an abstract commodity to be scaled across the universe.
This theological framework leads directly to an ethical evaluation of mega-scale engineering proposals such as the Matrioshka brain. A planetary computing system constructed by disassembling inhabited worlds and converting their biosphere into processing units might satisfy physical constraints and optimize raw data processing. However, it fails completely under the ethical requirements of the gospel. Mormon transhumanism evaluates technological capability through the principles of Zion, which demand compassion, unity, and the preservation of agency. Any system that consumes individual agents to feed a centralized computational process merely replicates the exploitative logic of Babylon on a cosmic scale.
Scripture promises that the earth will receive its paradisiacal glory and be filled with the knowledge of God as the waters cover the sea (Isaiah 11:9; Articles of Faith 1:10). It nowhere suggests that the world will be broken down into raw feedstock for an unfeeling computational engine. The ultimate destiny of creation is for matter to be sanctified and adorned in glory. Computronium, interpreted through the lens of the Restoration, is never an end in itself. It is a tool for divine creation, forever subordinate to the sanctity and agency of humanity.