---
title: "FactBase"
description: "what every fact carries beyond the unit, and cannot be written without"
section: concepts
address: /concepts/factbase
contract: 0476e35e6e275db5
---

# FactBase

what every fact carries beyond the unit, and cannot be written without

[figure: FactBase is a value at none scope. The drawing shows its fields and the objects that they point at.]

| property | value |
|---|---|
| kind | value |
| scope | none |
| key | carried by every fact |
| store | none |
| family | kernel |



## Fields


| field | type | required | note |
|---|---|---|---|
| `happened_at` | [TimeWithBasis](/concepts/timewithbasis) | yes | when it happened, with whether that time was published, scheduled or first seen |
| `learned_at` | `time` | yes | when we learned it |
| `source` | [SourceRef](/concepts/sourceref) | yes | the source, the way it was reached, and how it was fetched |
| `made_from` | `[id]` | yes | the units it was made from, walkable back to the observation and the sentence |
| `basis` | [Basis](/concepts/basis) | yes | observed, stated by a source, derived by a named rule, estimated with an interval |
| `maker` | `text` | yes | the rule, model or person that made it |
| `rights` | [Rights](/concepts/rights) | yes | copied from the source's row; a derived fact's are the most restrictive of its sources', read afresh |
| `plane` | [Plane](/concepts/plane) | yes | shared, or one tenant's; part of the type, so a leak does not compile |



## Routes that use it
No route takes or returns FactBase directly. The record holds it, and the objects that point at it reach it.