Simon's parable of Hora and Tempus is one of the most cited arguments for hierarchical, modular organization in complex systems. This notebook validates corrected analytical predictions (Turney 1989, Saltzer 1996) through faithful Python simulation, applies Shannon entropy to trace where information is committed during assembly, and identifies an unacknowledged agent in the parable — here called Secunda — whose invisible, costless work at every modular ratchet point is the sole source of Hora's advantage. We derive the conditions under which Secunda's contribution provides a net benefit, showing that modularity is advantageous only when the environment is hostile enough to punish linear development.

A computational re-examination of Herbert Simon's parable of the watchmakers from The Architecture of Complexity (1962), implemented as a marimo reactive notebook.