The commonplace book was an early reading tool for collecting quotes, writing thoughts and otherwise collating information from a time when owning books and access to written information was rare. There are many words for the modern versions of these, Knowledge Base, Second Brain, Digital Garden. I like Commonplace as it feels like it comes from a [[Folk]] History. Another way to think about this is as *documentation for your brain.* Documentation in the technical sense, is not thought about until needed. But good documentation is constant companion to what it describes. I often feel like my brain comes to different conclusions on the same matter in different contexts ([[The brain believes what it thinks]]). Documentation in the form of this commonplace helps me write down these often opposite, tangential thoughts so I can reference them, argue against them and otherwise incrementally increase whatever accuracy can be gained (see [[what these notes are]]).