Mule sterility

Use in the book

The reported explanation turns on the fit between unlike regions in the two contributions. The hollow portions of each meet the dense portions of the other, producing a compact result. The failure of further generation is therefore attributed to how materials combine, rather than simply to the absence of either contribution.

This is a particularly useful test of the mixture theory because combination does not always yield an ordinary fertile organism. A material process may produce a stable or dense result whose reproductive consequences differ from those of its sources. The comparison with metal hardened by tin reinforces the point that a mixture can acquire a quality not present in the same way in either ingredient.

The report must not be promoted into a directly quoted Empedoclean poem. Aristotle is paraphrasing an explanation for a particular problem, and the edition adds the mule context in its note. The evidence therefore supports a historically attributed account of sterility, not the exact original language of that account. It also does not support a modern treatment or general biological law for infertility.

Places to read

1. B 92 (report)Aristotle reports the complementary fitting of two soft seeds into a hard mixture.
2. B 92 (editorial discussion)The local apparatus identifies mule sterility as the explanatory target.

Translation in this edition

All Greek forms in this entry are from Aristotle’s report. The animal heading is warranted by the supplied contextual note, whose status is marked separately from the reported wording.

Use in the book

Aristotle says that the whole mule kind is infertile and criticizes Empedocles and Democritus for applying one explanation alike to all cross-kind matings. He calls Empedocles' account unclear. The excerpt then breaks off with “and so on,” so it does not reproduce the specific mechanism in full. Aëtius supplies an anatomical explanation: a small, low, narrow womb attached in the wrong direction cannot receive the seed. The edition's discussion instead connects Empedocles with B92's analogy of tin and copper making a harder compound, applying such hardening to mule seed. That comparison belongs to cross-volume editorial context, not the printed Aristotle clause here. The resulting discrepancy is important: anatomy and material mixture are different explanations, and it is not certain from this dossier how one replaced, complemented, or distorted the other.

Places to read

1. A 82 (polemical)Aristotle, On the Generation of Animals. Criticizes a general explanation of cross-kind infertility but abbreviates the specific Empedoclean argument.
2. A 82 (testimony)Aëtius. Explains barrenness through the shape, size, and position of the womb.
3. A 82 (apparatus)Modern commentary and apparatus. Refer to B92's tin–copper comparison for a different mixture-based explanation.

Translation in this edition

The source's universal claim about mules is reported historically, not presented as a carefully qualified modern zoological statement. The omitted Aristotle continuation must not be reconstructed as though it were printed in this volume.