Second brain
The idea
Your memory is good at having ideas and bad at storing them. A second brain moves the storing into a trusted system, so your head is free for thinking. Tiago Forte popularised the term with his course and book Building a Second Brain, and describes the process in four steps: capture, organise, distil and express.
- Capture what resonates, instead of trying to remember it.
- Organise it by where it will be useful — usually by project or area of your life, not by topic.
- Distil it down to the essence, so a future you can read it quickly.
- Express it: use it in your work.
Common tools
A second brain is a method, not an app. People build one in Notion, Obsidian, Apple Notes, Evernote, or plain text files. What matters is that capture is quick and that you trust you will find things again.
The gap: people
Second brains are usually organised around projects and topics. But a large share of what is worth remembering is about people: what a client told you about their plans, who recommended a book, the name of a colleague's partner, what an investor said they need to see.
That knowledge fits awkwardly. You can keep one note per person and link to it, and many people do. But it runs into the capture step harder than anything else, because it arises in conversation — when you are away from the keyboard and about to walk into the next thing.
Where Rucksack fits
Rucksack is not a general second brain. It does one part of the job: knowledge about people, captured by speaking. After a conversation you talk for half a minute, or type. It files the facts under each person you mentioned, asks when a name could mean two different people, and links every fact back to the recording — so the "distil" step keeps its source.
It does not replace Notion or Obsidian, and it does not connect to them: there are no integrations or import today. It is currently a closed beta.