From the book
Empedocles’ The Testimonia, Volume II
Empedocles of Acragas · Diotimos Editions · 2026
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At a Glance
- The wordTropikoi kykloi are turning circles, the celestial circles associated with the sun's seasonal limits.
- In this workAëtius explains the sun's return by what prevents it from continuing indefinitely in a straight course: the enclosing sphere and the tropic circles.
- In this editionThe bracketed words “[the sun turns back]” are the translator's restoration of context.
- A place to readThe enclosing sphere and tropic circles prevent indefinite rectilinear solar travel.
Meaning
Tropikoi kykloi are turning circles, the celestial circles associated with the sun's seasonal limits. The surrounding sphaira is a sphere enclosing the sun. Here the terms occur in doxographic prose, not a surviving Empedoclean verse.
Use in the book
Aëtius explains the sun's return by what prevents it from continuing indefinitely in a straight course: the enclosing sphere and the tropic circles. The sentence is unusually compressed, since its subject and the fact of turning are supplied in the translation. It presents a limit or obstruction, not an account of gravity or orbital mechanics. Nor does the report clarify whether the circles act as boundaries of the sphere, as separate constraints, or as geometrical descriptions of where a physical constraint is encountered. Its interest is nevertheless substantial: a recurring astronomical event is attributed to the arrangement of a bounded cosmos. The neighbouring report of a celestial tilt supplies a history of that arrangement but cannot resolve the precise relation between the two constraints.
Places to read
- A 58 (testimony)Aëtius, second notice. The enclosing sphere and tropic circles prevent indefinite rectilinear solar travel.
- A 58 (testimony)Aëtius, first notice. Provides the adjacent physical account of the heavens' inclination.
Translation in this edition
The bracketed words “[the sun turns back]” are the translator's restoration of context. They should not be mistaken for additional Greek preserved in the notice. This enclosing sphere is not automatically identical with the perfectly unified Sphairos of the cosmic-cycle testimonia.
Source note
The expression for indefinite straight travel does not state that the sun ever actually escaped its bounded route. The cause is expressed through what prevents such continuation.