Ptolemy's Almagest, a foundational text in astronomy, divided the celestial sphere into 12 equal parts for astrological purposes, a division that has persisted despite later astronomical discoveries revealing 13 constellations along the ecliptic. This arbitrary division, lacking clear justification, highlights how historical conventions can endure even when scientific understanding evolves.

Impact: Medium. This historical division by Ptolemy, while influential, demonstrates how arbitrary decisions can shape scientific and cultural understanding for centuries, even when not fully justified.

In the source video, this keypoint occurs from 00:24:47 to 00:26:09.

Sources in support: Emílio Garcia (Biologist)