From the book
Empedocles’ The Testimonia, Volume II
Empedocles of Acragas · Diotimos Editions · 2026
Browse this book’s lexicon →Orientation
At a Glance
- The wordThese expressions mean by day or in daytime.
- In this workAccording to Theophrastus's report, animals with less fire see better by day because external light compensates for their deficiency.
- In this editionThe account in §8 contains several supplements; A91 gives a related but not word-for-word identical formulation.
- A place to readExplains daytime acuity through external compensation for deficient internal fire.
Meaning
These expressions mean by day or in daytime. They occur in a comparative explanation of visual acuity, not as the name of a formally independent faculty. The comparison is with night vision and with different internal balances of fire and water.
Use in the book
According to Theophrastus's report, animals with less fire see better by day because external light compensates for their deficiency. More fire is not always better: excessive inner fire is increased by daylight and encroaches on water-passages, producing dim vision. Aristotle's parallel report identifies grey eyes as fiery and consequently poor in daytime for want of water.
Theophrastus contests the mechanism rather than merely denying variation among animals. If greater fire destroys lesser fire, deficient eyes should see less by day; if likeness increases likeness, everyone should see white better by day. He also appeals to the general superiority of daytime vision, apart from a few animals. That empirical generalization belongs to the critic's argument and should not be presented as an established biological law.
Places to read
- A 86 §§ 7–8 (testimony)2Theophrastus, On the Senses 8. Explains daytime acuity through external compensation for deficient internal fire.
- A 86 §§ 18–19 (polemical)Theophrastus, On the Senses 18. Challenges the predicted effects of sunlight on visual fire.
- A 91 (polemical)Aristotle, On the Generation of Animals. Reports and rejects the explanation of weak daytime vision in grey eyes.
Translation in this edition
The account in §8 contains several supplements; A91 gives a related but not word-for-word identical formulation. They should be compared rather than silently fused.