Grey Goo

In his 1986 volume Engines of Creation, K. Eric Drexler introduced the term grey goo to describe microscopic, self-replicating machines that escape human control and turn the living world into copies of themselves. He pictured “omnivorous ‘bacteria’” that “could spread like blowing pollen, replicate swiftly, and reduce the biosphere to dust in a matter of days,” and chose a drab name for replicators less inspiring than “a single species of crabgrass.” His book spells it gray; later debate, his own included, often has grey. The nanotechnologist Robert Freitas called the process ecophagy, joining the Greek for “household,” the root of ecology, to the Greek for “eating.”

Two responses to the scenario have dominated. In 2000, the computer scientist Bill Joy urged the relinquishment of research on self-replicating technologies, while others dismissed grey goo as science fiction. By 2004, Drexler regretted the coinage, and that year Britain’s Royal Society found self-replicating machines too distant to concern regulators. Most researchers in the field now consider runaway machine replication remote. Scripture treats replication as a gift and sets bounds on it from the start, and in that light, grey goo names what replication becomes when the bounds are gone.

After His Kind

Within the Genesis creation narrative, the injunction for living things to increase is inextricably bound to specific, divinely ordained limitations. The earth is commanded to bring forth “the fruit tree yielding fruit after his kind, whose seed is in itself” (Genesis 1:11-12). The Hebrew term min, translated as “kind” or “species,” establishes a foundational taxonomic boundary, ensuring that each creature multiplies strictly within its designated sphere. Furthermore, the blessing to “be fruitful, and multiply” is fundamentally teleological; the sea creatures are instructed to “fill the waters,” implying a state of completion rather than endless expansion. Within this interconnected biological web, each kind sustains or is sustained by others, preventing any single entity from consuming the whole.

Drexler’s ecophagic replicators deliberately subvert these ancient limits. Engineered to be omnivorous, they collapse the diversity of kinds into a single, sterile singularity, theoretically out-competing natural biological organisms. A contemporary analogue can be found in the recent warnings published in Science regarding the creation of mirror bacteria⁠—synthetic cells possessing reversed molecular chirality. Because such organisms would circumvent the immune defenses of existing flora and fauna, and remain unrecognized by natural predators like bacteriophages, they would exist entirely outside the established scriptural and ecological web of kinds, presenting an unmitigated risk without offsetting safeguards.

The Locust and the Leaven

The scriptural archetype of unrestrained, catastrophic multiplication is the locust swarm. The primary Hebrew noun for locust, ’arbeh, is traditionally understood to derive from the root rabah, the very verb employed in the divine mandate to multiply. Ancient Hebrew audiences would have readily discerned this semantic echo, recognizing the swarm as a destructive inversion of the creation blessing. The prophet Joel describes a succession of insect plagues that systematically deconstruct the agrarian ecosystem, driving the narrative of creation strictly in reverse: “the land is as the garden of Eden before them, and behind them a desolate wilderness” (Joel 2:3).

This arithmetic of exponential replication is similarly invoked in the New Testament imagery of leaven. Paul observes that “a little leaven leaveneth the whole lump” (1 Corinthians 5:6), a principle of geometric progression that Jesus likewise applies to the pervasive expansion of the kingdom of heaven (Matthew 13:33). Synthesizing these texts reveals that the mechanism of exponential spread is mathematically neutral; it is the nature of the proliferating agent that demands moral judgment. When Freitas modeled the thermodynamics of unchecked mechanical replication, he demonstrated that while ideal conditions might allow nanomachines to consume the biosphere in mere hours, the resulting thermal signature would be blindingly visible to orbital sensors. Conversely, a replication rate slow enough to evade detection would require years, affording a critical window for intervention.

Element, Law, and Bounds

Restoration theology fundamentally reframes creation as the purposeful organization of eternal, uncreated element⁠—a divine labor in which humanity is explicitly invited to participate. As Joseph Smith articulated in 1844, God possessed “materials to organize the world out of chaos,” underscoring the fact that matter “may be organized and re-organized; but not destroyed.” The prospect of molecular manufacturing⁠—the precise, atom-by-atom assembly of structures⁠—represents the logical extension of this organizing principle down to the nanoscale. Crucially, however, modern revelation insists that such organization cannot be arbitrary. As Doctrine and Covenants 88:38 dictates, “unto every law there are certain bounds also and conditions.” It is within this theological framework that the Mormon Transhumanist Affirmation summons its adherents to act as “compassionate creators” who diligently “identify and prepare for risks.”

In their 2004 analysis, Drexler and Chris Phoenix proposed engineering constraints that closely mirror these scriptural bounds. They advocated for the nanofactory: a localized, immobile array of molecular machines that neither consumes natural biomass nor contains its own replicative blueprints. Dependent entirely on an external stream of input instructions, such a mechanism remains inert absent deliberate and continuous control. Unlike the Genesis fruit tree, which houses its seed within itself, the safe nanofactory keeps its animating code wholly external. The specter of grey goo thus presents a profound moral imperative to modern creators: to retain sovereign control over replicative instructions, to utilize synthetic feedstocks, to permanently abjure the creation of autonomous replicators or mirror cells, and to govern molecular organization strictly within the bounds and conditions originally established for the preservation of all kinds.