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title: Parable of the Two Watchmakers
created: 2025-12-10T08:22:14
modified: 2025-12-10T08:33:27
---

The [Parable of the Two Watchmakers](https://en.citizendium.org/wiki/Parable_of_the_two_watchmakers) was introduced by Nobel laureate **Herbert A. Simon** to explain why **hierarchical, modular systems** evolve and survive better than tightly coupled ones. It illustrates how **complex structures are built far more efficiently when broken into stable sub-assemblies.**

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# The Story

There are two master watchmakers: **Tempus** and **Hora**.

* Both make extremely intricate watches, each containing **1,000 individual parts**.
* A phone rings often while they are working, forcing them to stop frequently.

## Tempus’ method (non-modular design):

* He assembles the watch **piece by piece**.
* If interrupted, the half-assembled watch falls apart.
* He must **start over from scratch** every time.

## Hora’s method (modular design):

* He builds **subassemblies** of 10 parts first.
* Then he combines 10 of these to create larger assemblies, and so on.
* If interrupted, only a small module is affected — the rest **stays intact**.

**Result:** Hora produces watches much faster and with far less wasted work, even though he and Tempus are equally skilled.

![](https://www.researchgate.net/profile/Jianguo-Wu-8/publication/300652614/figure/fig2/AS:451243538685954@1484596251403/llustration-of-the-watchmaker-parable-Based-on-the-description-in-Simon-1962.png)

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# Key Insights

* Complex systems are far more robust and evolvable when built out of smaller, stable, reusable components.
* Modularity is the key to building and sustaining complexity.
* Stable subsystems make complex structures more resilient.
* Interruptions (or disturbances, failures, shocks) punish non-modular systems but have minimal impact on modular, hierarchical ones.
* Systems that can “hold together” when disturbed will outcompete those that fall apart.