From the book
Empedocles’ The Testimonia, Volume II
Empedocles of Acragas · Diotimos Editions · 2026
Browse this book’s lexicon →Orientation
At a Glance
- The wordSymmetria denotes suitability of measure or correspondence of dimensions.
- In this workTheophrastus treats commensurability as the physical condition common to mixture, growth, and sensation.
- In this edition“Out of proportion” in §§14–15 translates forms from the same word family but may describe either a disordered blend or mismatched passages.
- A place to readUses oil and water’s reported failure to mix, unlike other liquids, in challenging the distinction between mixture and perception through passage correspondence.
Meaning
Symmetria denotes suitability of measure or correspondence of dimensions. Here “commensurability” normally concerns the relation between passages and entering material. It need not mean mathematical commensurability in the strict sense of two magnitudes having a common unit.
Use in the book
Theophrastus treats commensurability as the physical condition common to mixture, growth, and sensation. He expressly illustrates the reported account with oil and water, which do not mix, in contrast with other liquids that do. His objection is that passage correspondence also operates in such lifeless materials: what then distinguishes their mixing from perception and growth, if the same condition explains all three? His later argument is stronger: when a theory explains sensory exclusivity by mismatched passage sizes, commensurability seems sufficient and elemental likeness becomes idle.
Plato's definition of colour adds both “commensurate with sight” and “perceptible.” Those are two predicates in the definition; the final word should not disappear into the first. Alexander similarly reports correspondences between magnetic passages and iron effluences, then asks why such correspondence does not make other bodies move together. Across these witnesses the important issue is explanatory discrimination: what makes an appropriate dimensional relation specifically visual, cognitive, or magnetic?
The term should also be distinguished from the equal or balanced blend of blood and from ratios constituting tissues. They can all be rendered with words such as proportion, but the relevant relations differ.
Places to read
- A 86 §§ 12–13 (polemical)Theophrastus, On the Senses 12. Uses oil and water’s reported failure to mix, unlike other liquids, in challenging the distinction between mixture and perception through passage correspondence.
- A 86 §§ 14–15 (polemical)Theophrastus, On the Senses 15. Says commensurability alone seems sufficient on the reported theory.
- A 92 (reception)Plato, Meno. Defines colour as an effluence commensurate with sight and perceptible.
- A 89 (polemical)2Alexander of Aphrodisias, Questions. Tests why matching passages produce attraction only in the magnetic case.
Translation in this edition
“Out of proportion” in §§14–15 translates forms from the same word family but may describe either a disordered blend or mismatched passages. The object of the relation must be supplied from context. The named oil–water contrast belongs to the ancient reported explanation, not a claim that pore correspondence is the modern explanation of immiscibility.