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Apr 7, 2026
The Library of Babel
How AI Systems Are Redrawing the Map of What We Know & Believe
Jorge Luis Borges’ story The Library of Babel conceives of the universe as a vast, infinite library composed of hexagonal galleries that contain every possible book that could exist. Although the vast majority of these books are pure gibberish, the laws of probability dictate that the library must also contain every coherent book ever written, or that could ever be written, including biographies of every person, predictions of the future, and most notably a perfect index of the library itself.
The story explores the existential despair and religious heresies of the librarians who inhabit this chaotic universe, as they struggle to find meaning in a place where all knowledge that has ever been or will be is buried beneath an overwhelming sea of nonsense…
The tragedy is not their failure to find this master index; it’s that they don’t realize the catalog they seek would itself need cataloging, creating an infinite regress of competing and contingent systems, each one claiming authority over the last.
We are living in that library now. Except the catalogers are not human, and what they choose to index determines not just what we find, but what we believe to be true.
In 2025, SEMrush conducted an experiment that exposed the scaffolding behind our new reality. They fed 2,500 queries, ordinary questions like “What’s a good project management tool?” or “Which laptop is best for video editing?” into ChatGPT and Google’s AI Mode, tracking which brands surfaced in the answers and which sources were cited as evidence. What they discovered was a fault line running through the consolidating digital landscape: the companies dominating traditional search rankings often evaporated entirely when an AI system answered the same question.
The technical term for this is visibility divergence.
The Geography of Mentions
Consider Microsoft and Google, who appear together in 78% of ChatGPT’s responses about digital technology and 82% of Google’s. This is not collusion, but rather gravitational pull. When two objects are massive enough, they warp the space around them, making it nearly impossible to discuss the territory without referencing both landmarks.
But mass alone does not guarantee presence. Zapier—a company most people would struggle to describe at a dinner party—ranks as the number one cited source in technology search queries while placing 44th in brand mentions.
Zapier is everywhere and nowhere: the ductwork in the walls, essential but unnoticed. Their How-To articles and integration guides make them useful to machines constructing answers, even as humans rarely think to recommend them.
This is the new cartography.
There are two maps of the same territory, and they barely overlap.
SEMrush found that 65% of the top 100 mentioned brands appear in both ChatGPT and Google AI Mode. That seems like consensus until you examine their citations. Only 32% of the top 100 cited sources overlap. In financial services, that number drops to only 16%. Imagine two historians writing about the same war, mentioning the same generals, but footnoting entirely different archives. One consults letters; the other, battle reports. Both claim accuracy. Neither is wrong, per se. But the version of events they construct, the truth they transmit, diverges within the details of each citation.
The Two Chambered Heart
SEMrush’s researchers identified what they call a “two-stage AI decision process,” surfacing a circulatory metaphor.
Stage One is the atrium: open, receptive, gathering fluid from everywhere. Here, AI systems behave like anthropologists in a foreign land, listening to what locals say in markets and cafés. They scan Reddit threads, Amazon reviews, Quora debates: the messy, contradictory chorus of user-generated opinion. This is where brands become mentioned.
Patagonia dominates 21.2% of fashion queries not through advertising, but through cultural saturation: the internet has reached a rough consensus that Patagonia signals ethical consumption in the same way Kleenex means tissue.
Stage Two is the ventricle: selective, pressurized, pushing only certain elements forward. Here, AI shifts from listening to fact-checking. It wants Wikipedia entries, official documentation, structured data—information that can be verified and parsed without ambiguity. This is where citations live, where Bankrate (86.6% citation rate in Google AI Mode for finance) exists as infrastructure rather than recommendation.
Most brands live in only one chamber. The rare few that circulate through both are the ones the system keeps pumping through its networks. Only 27 brands out of the top 100 achieve this dual presence.
The rest are either invisible because people discuss them but machines can’t verify them, or machines cite them but people never talk about them.
The Garden of Forking
In Borges’ The Garden of Forking Paths, the protagonist encounters a novel in which every possible outcome of every decision actually occurs, each spawning its own timeline… The book is incomprehensible because it refuses to choose.
Our AI systems have made the opposite choice: they choose constantly, ruthlessly, invisibly. And their choices differ.
When you ask ChatGPT about financial services, the top source it consults is Reddit, appearing in 176.9% of responses (the percentage exceeds 100 because sources can appear multiple times), followed by Wikipedia and Investopedia. When you ask Google AI Mode the same question, the hierarchy is completely different: Bankrate (86.6%), NerdWallet (75.1%), and Investopedia.
It’s the same question. Different answers.
YMYL
The divergence is most extreme in domains Google has long termed YMYL—”Your Money or Your Life”—subjects where getting the answer wrong can ruin someone.
Here, the disagreement over what constitutes a trustworthy source becomes existential. Is community consensus (Reddit) more reliable than professional aggregation (NerdWallet)? Is the wisdom of crowds wiser than the curation of experts?
The systems have answered differently, and so the reality they construct, the financial landscape visible to their users, forks into parallel versions of reality.
In one, SoFi barely registers (12.7% weighted share of voice, the only fintech in the top mentions). In both, legacy institutions like Fidelity (33.7%) and Vanguard (29.28%) dominate, but the evidentiary trail leading to their dominance branches through entirely separate ecosystems.
We used to worry about online bubbles that filter our realities, where people would see different information based on their preferences. We are now seeing something stranger: people asking neutral questions and receiving definitive, diverging answers constructed from different epistemologies, creating large gaps of misunderstanding.
The Accessibility Problem
There is a technical requirement buried in SEMrush’s appendix that would have seemed mundane in 2015: ensure your content uses static HTML, is crawl-able, includes structured markup, etc.
Many modern websites, especially those built on JavaScript frameworks, render content dynamically. For human visitors, this creates smooth, app-like experiences. For the crawlers that feed AI training datasets, it creates a kind of opacity, like trying to read a book through frosted glass.
If an AI model cannot parse your product specifications, your warranty terms, your FAQ, then it cannot cite you. You may have the most comprehensive information in your industry, formatted beautifully for human eyes, and be completely invisible to the systems mediating discovery.
This is a new form of literacy: not how well humans can read you, but how well machines can. And unlike traditional literacy, which develops gradually through education, machine-legibility often requires retroactive restructuring of existing infrastructure, and cuts faster and harder at the edges.
Companies that spent millions optimizing for Google’s traditional search algorithms in 2015 may find themselves invisible in 2025 because the medium through which content is accessed shifted beneath them. It’s like discovering that your entire library was cataloged in a language the new librarians can’t read, and they’ve decided that anything not in their catalog doesn’t exist.
The Commons Before Enclosure
If every company now engineers for AI visibility the way they once engineered for SEO, the signals will degrade. Reddit already struggles with astroturfing—corporate accounts posing as enthusiastic users. Imagine that scaled to an industry mandate. Wikipedia’s volunteer editors wage constant war against promotional editing; now imagine that every brand assigns teams to “improve” their Wikipedia presence.
We may be witnessing the brief window when user-generated content still functions as reliable signal—a digital Commons before the Enclosure Acts, that historical moment when shared land was fenced and privatized, and the landscape itself was restructured to serve commercial interests.
The alternative future is already visible in outline: a Heisenberg uncertainty principle for brand presence where the act of measuring and optimizing for AI visibility changes what AI visibility means… until the metrics decay into noise and new ones must be found, in an infinite regress of cataloging systems, each claiming authority over the last.
The Test
There is a diagnostic available now, in this transitional moment.
If you are mentioned but not cited, you exist in culture but not in the machinery of fact. People talk about you; machines don’t trust you enough to quote you. You are folklore.
If you are cited but not mentioned, you are infrastructure—useful, invisible, easily replaced when something more useful appears. You are plumbing.
It’s not yet clear which audience matters more: the humans deciding what’s worth discussing, or the machines deciding what’s worth remembering.
The uncomfortable possibility is that the question is already obsolete—that “human” and “machine” audiences have become so entangled, so mutually constitutive, that distinguishing between them is like asking whether it’s the map or the territory that determines where you can go.
The answer, as with most things Borges understood better than we do, is both, and neither; the question itself is the territory we’re trying to map.