Fact Base

Last updated: Jun 9, 2026

About This Tool

Fact Base is a personal record of things you have established to be true. Instead of trusting memory — which fades and quietly distorts — you write each fact down with the details that let you trust it later. It is deliberately more than a notes app: every fact carries where it came from and how sure you are, so the difference between something you have verified and something you are still guessing at never gets lost.

How to Use

Add a fact as a clear statement, then record its source, the date you learned it, and how sure you are.
Optionally note which decision or question the fact bears on, and add a tag or two — a fact worth storing is usually one that could change a decision.
Search, filter by confidence, or sort your facts to find what you know the moment you need it. Edit any fact as your confidence changes.

Methodology

Writing information to a reliable external store is known as cognitive offloading; research shows it frees limited working memory for other tasks, and that the benefit depends on genuinely trusting the store. The hardest thing for memory to keep is not the fact itself but where you learned it, so Fact Base treats the source as a first-class part of every entry. It also nudges you to save facts that could change a decision, rather than collecting trivia.

Sources: Risko & Gilbert (2016) · Johnson, Hashtroudi & Lindsay (1993)

Understanding Your Results

Each fact carries a confidence level. Established means you have verified it and would stake a decision on it. Probable means the evidence is good but not conclusive. Uncertain means it is still a working belief, not a settled fact. Be honest with these labels — that honesty is the point. A store where everything is marked Established is no more trustworthy than memory. Marking something Uncertain is not a weakness; it is an accurate map of what you actually know.

Practical Examples

Planning a move, you save "the lease requires 60 days' notice" with the source "signed lease, page 3," dated today, marked Established. Months later you act on it without re-reading the whole contract or trusting a vague memory. Researching a purchase, you save "this model averages 4.3 stars over 2,000 reviews" from a retailer page, marked Probable. When a salesperson calls it "the best on the market," your recorded fact — with its source — keeps you anchored to what you actually know.

Tips for a fact base you can trust

Always fill in the source. Where you learned something is the first thing memory loses, and it is what lets you re-check a fact later. Rate confidence honestly. Reserve Established for facts you have actually verified; most new entries are Probable, and that is fine. Store facts that matter. If a fact could change a decision, it earns its place; if it would not, you can skip it. Revisit and update. Evidence changes — a fact that was Established last year may need downgrading, and an Uncertain belief may earn a promotion.

All calculations are performed locally in your browser. No data is sent to any server.

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Frequently Asked Questions

What is a fact base?

A fact base is a personal store of things you have established to be true, kept outside your memory. Each entry is a clear statement saved with its source, the date you learned it, and how sure you are. Instead of straining to recall details, you look them up in a place you trust — which frees your attention for the decision in front of you.

How is this different from a notes app?

A notes app stores text; a fact base stores text plus the things that make it trustworthy. Every entry carries an explicit source and a confidence level, and you can flag which decision it affects. That structure keeps the line between what you have verified and what you are still guessing at — a line ordinary notes quietly blur.

Why record a source for every fact?

Because the source is the first thing memory loses. Research on source monitoring shows people often remember a fact but misremember — or invent — where it came from, which makes it hard to know whether to trust it. Recording the source at the moment you save a fact lets you re-check it later and judge how much weight it deserves.

What do the confidence levels mean?

Established means you have verified the fact and would act on it. Probable means the evidence is good but not conclusive. Uncertain means it is still a working belief. The levels double as a gate between fact and belief, so a quick guess never quietly hardens into something you treat as proven. Update a level whenever your evidence changes.

Does writing things down weaken my memory?

There is no solid evidence that offloading facts to a trusted store harms your long-term memory. What research does show is that it frees up limited working memory for the task at hand. You will naturally rely on the store for offloaded details — that is the point — so the practical advice is simply to keep the store reliable and well-sourced.

What should I store — and what should I leave out?

Favor facts that could change a decision. A useful fact is one that discriminates between your options or that you would be in trouble for getting wrong; a fact that merely confirms what you already assumed adds clutter without adding value. When you add a fact, the tool gently asks what it affects — if the honest answer is "nothing," you can usually skip it.

Is my data private?

Yes. Every fact you add is saved only in your own browser on this device, and nothing is sent to any server. Because the data is local, clearing your browser storage will remove it — so use the export option to keep a backup, and the import option to move your facts to another device.

Can I export my facts or move them to another device?

Yes. Use Export to save all your facts to a file you can keep as a backup, and Import to load that file on another device or after clearing your browser. Because everything is stored locally, exporting regularly is the safest way to make sure you never lose your record.