Most of Human History Is Unknown

Human history is largely a record of what survived—because major knowledge losses have repeatedly erased whole libraries, entire civilizations’ written traces, and even centuries of progress. The most striking example is Nalanda University, founded in 427 CE in medieval Magadha (present-day Bihar, India), which grew into a residential learning hub drawing tens of thousands of students across Asia. Over time it amassed an estimated nine million manuscripts across medicine, logic, mathematics, philosophy, astronomy, and religion. Around 1193 CE, the university was destroyed by fire—commonly attributed to Turko-Afghan general Bakhtiyar Khilji during a campaign meant to remove competing teachings—leaving behind only ash and dust and wiping out a vast store of accumulated intelligence. The loss matters not just for what is known to be gone, but for what might never be recoverable: innovations derailed, questions never asked, and gaps that permanently reshape how later generations understand the world.

That fragility is not limited to medieval disasters. Before writing existed, information relevant to human history lived mostly in brains, and brains are poor long-term storage for “empire-sized databases.” As Yuval Noah Harari is quoted, human memory is limited, dies with individuals, and becomes garbled across transmissions; brains also evolved for survival tasks rather than large-scale numerical recordkeeping. Writing changed that. The first widely known systems emerged around 3400 BCE among the Sumerians, whose scribes used clay tablets with pictorial marks that evolved into cuneiform symbols for counting supplies and managing infrastructure. Writing later developed in Egypt (hieroglyphs) and China (oracle-bone script), then spread and diversified as neighboring cultures adapted the idea. Over centuries, writing moved from clay and animal skins toward paper, then printing, and eventually digital formats—making knowledge easier to copy, scale, and distribute.

Yet writing’s endurance has never eliminated vulnerability. The history of literacy is also the history of destruction: Julius Caesar’s accidental burning of the Library of Alexandria in 48 BCE (with estimates ranging from 40,000 to several hundred thousand books lost), Franciscan missionaries burning nearly all Maya written records in the mid-sixteenth century, and repeated library looting and destruction during the Visigoths’ sack of Rome in 410 CE and the Sack of Rome in 1527. Even the way historians know about these events depends on what writing survived—fossils, artifacts, architecture, and myths can fill some gaps, but much of what people “dependably know” comes from records that made it through.

The result is a persistent blind spot: most of human history—especially the millions of years before writing—remains unknown, and even the written era is riddled with voids. Cultural beliefs today, including religions, ideologies, and ideas about race and gender, rest on an “imagined order” built from surviving fragments. Harari’s warning captures the modern twist: censorship now often works by flooding people with irrelevant information, while power increasingly means knowing what to ignore. Even with today’s backups and digital storage, risks remain—misinformation, echo chambers, explicit censorship, cyber-attacks, natural disasters, and human self-destruction. The central takeaway is stark: preserving knowledge is not just a technical task, but a defense against becoming another historical mystery.