---
slug: "ExogenousStress"
name: "ExogenousStress"
type: "Dynamics"
layer: "Physics"
ref: "ExogenousStress#6a33"
sema_id: "sema:ExogenousStress#mh:SHA-256:6a33d65f1361a95ad72b8a8d59c90bf253e08f804e2a79532977d5113987b672"
tags: ["Physics","Dynamics"]
updated: 2026-11-11
mindscape: "origin-of-risk"
index_url: https://mindscape.pages.dev/origin-of-risk/index.json
url: https://mindscape.pages.dev/origin-of-risk/ExogenousStress/
related: ["EndogenousStress","FractionalMetaModel","RedQueenRace","StoppingRule"]
---

# ExogenousStress

An external event or change in requirements that the current shape does not handle and that forces it to change

Layer: Physics · Category: Dynamics

## Mechanism

A system (software architecture, organism, organisation) has a current shape that copes with a certain set of conditions. An exogenous stressor is an event from outside that falls outside that set: a supplier fails, a power outage, a new pathogen, a changed regulation, a requirement nobody predicted. The system survives only if it can change shape fast and cheaply enough to absorb the stressor. Stressors are often unpredictable in probability but can still be imagined as possible, and a design can be prepared by working out which of its parts would need to change for each stressor. Exogenous stress is the external counterpart of endogenous stress, the internal load a system carries from being prepared for it.

## Invariants

- The stressor originates outside the system
- Surviving it requires a change of shape, not only correction back to the current shape
- A stressor can be planned for as possible without knowing its probability

## Failure modes

- Only planning for stressors whose probability can be estimated, so stressors that are possible but cannot be estimated are missed
- Treating survival of one stressor as proof of robustness to all

## Builds on

—

## Used by

- [EndogenousStress](https://mindscape.pages.dev/origin-of-risk/EndogenousStress.md) (Mind; References)
- [FractionalMetaModel](https://mindscape.pages.dev/origin-of-risk/FractionalMetaModel.md) (Mind; References)
- [RedQueenRace](https://mindscape.pages.dev/origin-of-risk/RedQueenRace.md) (Physics; References)
- [StoppingRule](https://mindscape.pages.dev/origin-of-risk/StoppingRule.md) (Mind; References)

## Identity

- Sema ID: `sema:ExogenousStress#mh:SHA-256:6a33d65f1361a95ad72b8a8d59c90bf253e08f804e2a79532977d5113987b672`
- Ref: `ExogenousStress#6a33`

## Links

- [Pattern page](https://mindscape.pages.dev/origin-of-risk/ExogenousStress/)
- [View in the interactive graph](https://mindscape.pages.dev/origin-of-risk/#ExogenousStress)
- [JSON](https://mindscape.pages.dev/origin-of-risk/ExogenousStress.json)
- [Index of all patterns](https://mindscape.pages.dev/origin-of-risk/index.json)