The Indexer's Folly: On John Locke's Scrambled Commonplace
We often imagine the great minds of the past as producing timeless thoughts from an innate wellspring of genius. Their notebooks, we assume, must be things of pristine order, elegant systems through which wisdom flowed as smoothly as ink. The reality is frequently more chaotic, more human, and in its own way, more instructive. Consider the case of John Locke, the 17th-century philosopher whose ideas on government and the self helped shape the modern world. This same man also authored a meticulous, almost obsessive, guide to managing information. He called it 'A New Method of a Common-Place Book,' and at its heart was a beautifully strange and slightly absurd indexing system that feels remarkably relevant to our own digital predicaments.
Locke’s problem was a familiar one: how to find what you’ve stored. A commonplace book was a repository for quotes, observations, and ideas gathered from reading. The danger was that a brilliant note on, say, morality, once transcribed under a general heading like 'Virtue,' might be lost forever, inaccessible if you later tried to recall it under a related but different term like 'Ethics' or 'Character.' Locke’s solution was a kind of pre-digital hash table. He would assign each two-page spread in his notebook a number. To index an entry, he would take the first letter of its first significant word (excluding articles like 'A' or 'The') and the first vowel that followed it. The combination of this letter and vowel would point him to the specific page number where the note resided.
It sounds simple, but the genius—and the folly—is in the example he gave. To index a quote beginning 'Aristoteles de humoribus' (Aristotle on humours), he would take the first letter, 'A', and the next vowel, 'i'. This 'Ai' combination, according to his master table, would direct him to page 43. So far, so logical. But what about a note starting with the word 'Abstinentia' (Abstinence)? The first letter is 'A', the next vowel is... also 'i'. 'Ai' again. Page 43. The same page as Aristotle’s humours. And a note starting 'Amicitia' (Friendship)? 'A' followed by 'i'. Page 43.
This is the indexer’s folly laid bare. Locke, in his quest for a perfect, mechanical system of retrieval, created a method that would pile wildly disparate subjects onto the same page. The mundane brilliance of it is that it worked precisely because it abandoned the idea of categorizing by subject, a task that requires constant, fallible human judgment. Instead, he outsourced the 'filing' to an arbitrary, unthinking rule based on spelling. It removed the friction of decision-making at the moment of capture. The system’s job wasn’t to create a perfectly ordered library of thought; its job was to guarantee you could, eventually, find the book you were looking for, even if it was shelved between two completely unrelated volumes.
There’s a lesson here for our own era of digital hoarding. We spend immense energy on our taxonomies, crafting intricate folders, tags, and databases, trying to anticipate the future selves who will need this information. We seek a clean, logical map of our knowledge. Locke’s method suggests a different priority: focus on the retrieval mechanism, not the initial categorization. Embrace a little chaos at the point of entry, as long as you have a reliable, if quirky, way to search it later. In an age of full-text search, his alphabetical-vowel trick seems quaint. But the principle—that a simple, consistent, and even slightly foolish-seeming rule can be more robust than a complex, intellectualized hierarchy—is a quiet rebuke to our own curatorial anxieties. Sometimes, the best way to manage knowledge is not to try and organize it perfectly, but simply to have a good, if unconventional, way of finding it again.
Notes & further reading
A few pages I came back to while writing this: