You don't have a thinking problem. You have a coverage problem.
The average knowledge worker has their best ideas in the shower, on a walk, at 2 AM, or mid-conversation — and captures almost none of them. Not because they lack discipline. Because they lack tools in the right places.
David Allen identified this problem decades ago. In Getting Things Done, he argued that your mind needs an "airtight external system" to capture every commitment, idea, and open loop — and that the system only works if a capture tool is available everywhere you go. Allen called this ubiquitous capture: the practice of ensuring you always have a way to externalize a thought within seconds, regardless of where you are or what you're doing.
The word ubiquitous is doing real work in that phrase. Not "convenient." Not "usually available." Ubiquitous — present in every context where thinking happens. Because the contexts where your most original thinking occurs are systematically the ones where capture tools are absent.
Why context matters: ideas are bound to environments
In 1975, Godden and Baddeley ran their landmark experiment on context-dependent memory. Scuba divers learned word lists either on land or underwater, then tried to recall them in the same or opposite environment. The finding: words learned underwater were best recalled underwater, and words learned on land were best recalled on land. Memory isn't just stored — it's encoded with the environmental context surrounding it.
Tulving and Thomson formalized this in 1973 as the encoding specificity principle: memory retrieval is most effective when the cues present at encoding are also present at retrieval. Your brain doesn't store thoughts in a vacuum. It binds them to the room you were in, the sounds you were hearing, the physical state of your body.
Here's what this means for capture: when you have a breakthrough insight while walking through a park, that thought is partly encoded with the feeling of movement, the ambient noise, the visual field. Sit down at your desk an hour later and try to reconstruct it? The retrieval cues don't match. You remember that you had an insight. You've lost what it was. The context where the thought was born is the context where it's easiest to capture — and the context where most people have no capture tool at all.
This is not a memory weakness you can train away. It's a structural feature of how human encoding works. The solution isn't better recall. The solution is capture tools that meet you where the thinking happens.
A 500-year lineage of capture tools
The challenge of capturing thoughts across contexts is ancient. The tools have changed. The problem hasn't.
Commonplace books (1500s–1800s). During the Renaissance and Enlightenment, educated Europeans maintained commonplace books — personal notebooks where they copied quotes, observations, recipes, arguments, and fragments from their reading. John Locke published an entire indexing method for commonplace books in 1706. The form was a response to the information explosion created by the printing press: too many ideas, too little working memory. The solution was externalization into a portable, personal repository.
Pocket notebooks (1800s–1900s). The industrial revolution made paper cheap and binding fast. Pocket-sized notebooks became standard equipment for writers, scientists, and engineers. Darwin carried a notebook on the Beagle. Edison filled 3,500 notebooks over his career. Mark Twain patented a self-adhesive scrapbook. The principle was the same: if you think in many environments, you need a capture tool that travels with you.
Index cards and the Zettelkasten (1900s). Niklas Luhmann maintained 90,000+ index cards over 40 years, producing 70+ books. His system worked because individual cards were atomic, addressable, and small enough to carry in a pocket. The capture happened wherever Luhmann was — the processing happened later, at his desk.
The smartphone (2007–present). The iPhone collapsed phone, camera, voice recorder, and notebook into a single device that's almost always within arm's reach. For the first time in history, most people carry a high-fidelity capture tool at all times. The bottleneck shifted from hardware availability to software friction — how many taps stand between you and an externalized thought?
Each era's innovators solved the same problem: how do I ensure a capture tool is present in every context where I think? The technology changes. The principle doesn't.
The modern capture ecosystem
You don't need the "best" tool. You need the right tool for each context. Here's how the current ecosystem maps to real capture scenarios:
Always-on-body tools (latency under 5 seconds):
- Apple Notes / Google Keep — Zero-config, widget on lock screen, syncs instantly. The best fast-capture tool for most people because it's already on the phone they carry. No login, no loading screen, no decisions.
- Voice memos — Faster than typing when walking, driving, or exercising. The native voice memo app on any smartphone works. Say the thought. Process it later.
- Pen and pocket notebook — No battery, no loading time, works in bright sunlight and airplane mode. A Field Notes notebook in your jacket pocket is still one of the lowest-latency capture tools ever invented.
Desk-bound tools (latency 5–15 seconds):
- Obsidian — Local-first, Markdown-based, 700+ community plugins. Excels at linking ideas, building structure, and long-form processing. Poor as a fast-capture tool unless you're at your computer. Its strength is as a destination for thoughts captured elsewhere.
- Notion — Combines notes, databases, tasks, and wikis. Powerful for structured processing. Too heavy for in-the-moment capture — the loading time and page hierarchy create friction that kills spontaneous externalization.
- Logseq / Roam Research — Daily-note-first design makes capture faster than page-based tools. Good for desk capture. Still requires a keyboard and focused attention.
Bridge tools (connecting capture to processing):
- Readwise — Syncs highlights from Kindle, articles, PDFs, and podcasts into a single stream. Not a capture tool itself, but it automates capture from reading contexts that most people otherwise lose.
- Drafts (iOS/Mac) — Opens to a blank page instantly. Every text starts as a draft, and you decide where it goes later. Purpose-built for the "capture first, organize never" philosophy.
The critical insight: no single tool covers every context. The person who captures effectively in 2026 typically uses 2–3 tools in a deliberate stack: a fast-capture layer (phone notes, voice memos, or pocket notebook) feeding into a processing layer (Obsidian, Notion, or Logseq). The capture layer optimizes for speed. The processing layer optimizes for structure. Confusing the two is how people end up with powerful tools they never actually use in the moment.
Why one tool is not enough (and why ten is too many)
BJ Fogg's Behavior Model, developed at Stanford's Behavior Design Lab, states that three elements must converge for a behavior to occur: Motivation, Ability, and a Prompt. For capture to happen consistently, you need all three — but Fogg's research shows that Ability (how easy the behavior is) matters more than Motivation in sustaining a habit. You can't rely on willpower to overcome friction. You have to reduce the friction.
Fogg defines ability through six factors: time, money, physical effort, mental effort, social deviance, and non-routine. A capture tool fails when it scores poorly on any of these. Pulling out a laptop during a dinner conversation to jot a note? High social deviance. Opening Notion to capture a shower thought? High time and physical effort (you're wet and the app takes 4 seconds to load). The behavior won't happen consistently, regardless of how motivated you are.
This means you need different tools for different contexts — a tool optimized for the specific friction profile of each environment. But here's the counterforce: Hick's Law, formulated by psychologists William Hick and Ray Hyman in 1952, demonstrates that decision time increases logarithmically with the number of choices. More options means slower decisions. When you have seven capture tools and a thought arrives, the question "where should I put this?" introduces friction that kills capture speed.
Research on context switching supports this. Studies show the average knowledge worker uses 10+ tools daily, and task-switching costs up to 40% of productive time. Each tool switch introduces a recovery period — Gloria Mark's research at UC Irvine found it takes an average of 23 minutes to fully regain focus after a significant interruption.
The sweet spot is typically two to three tools:
- One fast-capture tool that's always on your body (phone widget or pocket notebook)
- One voice-capture tool for hands-free contexts (native voice memo or a dictation app)
- One processing tool where captured material goes to be organized (Obsidian, Notion, or similar)
This stack covers every context without creating decision paralysis. When a thought arrives, you don't ask "which tool?" You use whatever is closest. The thought lands in an inbox. The sorting happens later.
The coverage audit: finding your blind spots
Most people have decent capture coverage at their desk and poor to nonexistent coverage everywhere else. The thinking contexts that matter most are usually the ones with the worst tooling:
| Context | Typical tool gap | Fix | | ----------------- | ---------------------------------------- | ------------------------------------------------------------------------- | | Shower / bath | No tool at all | Waterproof notepad (Aqua Notes), or shout at a voice assistant | | Walking / running | Phone in pocket but too slow to pull out | Voice memo shortcut on lock screen or Apple Watch | | Falling asleep | Phone is charging across the room | Bedside notepad and pen, or phone on nightstand with voice memo | | Driving | Hands occupied, eyes on road | Voice command: "Hey Siri, note..." or dedicated voice recorder | | Meetings | Social pressure not to type | Pocket notebook under the table, or a single open note on your phone | | Reading | Highlights trapped in the book | Kindle highlights + Readwise sync, or photograph the page | | Conversations | Awkward to pull out a device | Train the post-conversation habit: 30-second voice dump immediately after |
The goal isn't to capture everything. The goal is to eliminate contexts where capture is impossible. Every gap in your tool coverage is a systematic leak in your thinking pipeline. You'll never know what you lost — that's what makes the problem invisible.
AI as the third capture layer
Your first brain generates thoughts. Your second brain (the capture system) preserves them as raw material. In 2026, a third layer has emerged: AI that operates on your captured material to find connections, surface patterns, and extend your thinking beyond what working memory allows.
This changes the economics of capture. In a pre-AI world, the value of a captured thought was limited to your ability to manually find it, remember it existed, and connect it to other thoughts. Now, every captured thought enters a corpus that AI can cross-reference with everything else you've ever externalized. A shower insight from Tuesday can be automatically linked to a reading highlight from six months ago and a meeting note from last week. The compound value of each captured thought has increased dramatically.
Tools like Mem, Notion AI, and Obsidian's AI plugins are already doing this — surfacing relevant past notes when you're writing, suggesting connections you didn't see, and summarizing patterns across hundreds of entries. But the fundamental constraint hasn't changed: AI can only work with what you've externalized. A brilliant connection between two ideas that were never captured is a connection that will never be found — not by you, not by any system.
This makes ubiquitous capture more important than it has ever been. Every uncaptured thought isn't just a lost idea. It's a missing node in an increasingly powerful network. The cost of a coverage gap in your capture tools compounds over time as the corpus grows and the AI gets better at finding connections within it.
The principle beneath the tools
Tools change every few years. The principle doesn't: capture coverage must match thinking coverage. Wherever you think, a tool must be present. The tool doesn't need to be powerful. It needs to be there.
David Allen didn't care whether you used a Palm Pilot or a paper notepad. Luhmann didn't care whether his cards were perfectly written. Tiago Forte explicitly advises against analyzing whether a thought is worth keeping in the moment — "spending too much energy on analytically deciding whether the content is worth keeping takes away your energy for being creative." Capture everything that resonates. Sort later.
The sorting is exactly where the next lesson goes. Once you've installed capture tools in every thinking context, you'll quickly face a new problem: thoughts scattered across voice memos, phone notes, index cards, and notebook pages. That scatter isn't a failure — it's proof that your capture coverage is working. But scattered thoughts that never get processed are barely better than uncaptured thoughts.
In L-0043, you'll build a single inbox for your thoughts — one place where everything captured flows, and one regular practice for processing it. Ubiquitous capture gives you the raw material. Inbox zero for thoughts turns that raw material into something you can actually use.