Why Birds, Oviparous Quadrupeds, and Seals Lack Ears

Notes

1. 12τὸ ἔχειν μὴ τρίχας ἀλλὰ πτερωτὰ εἶναι — The two infinitive phrases (`ἔχειν` and `εἶναι`) introduced by the article `τὸ` are connected by `καὶ` and serve as the object of the preposition `διὰ`. The subject of the infinitives is the preceding `οἱ ὄρνιθες` (birds, masculine/feminine), but the predicate adjective `πτερωτά` is neuter plural. This suggests that birds are treated generally as neuter (akin to `τὰ ὄρνεα`) or the subject is generalized.
2. 12οὐκ οὖν ἔχει — The subject of the third-person singular verb `ἔχει` is not explicitly stated in the text, but from the context, it is appropriate to supply "Nature" (`ἡ φύσις`) as the active agent that fashions physical structures.
3. 12ἐξ ἧς ἂν ἔπλασε τὰ ὦτα — In the clause introduced by the relative pronoun `ἧς` (referring back to `τοιαύτην ὕλην`), `ἄν` is used with the indicative aorist (`ἔπλασε`), expressing past potentiality ("might have fashioned") or a contrafactual condition ("would have fashioned, had there been material").
4. 12διὰ τὸ πεπηρωμένον εἶναι τετράπουν — An accusative-and-infinitive phrase introduced by `διὰ τὸ` expressing cause. Although the logical subject of `εἶναι`, namely the seal (`ἡ φώκη`), is a feminine noun, the predicate `πεπηρωμένον τετράπουν` (a stunted quadruped) is neuter singular. This is because the seal is conceptualized in context under the neuter category `ζῷον` (animal), or the predicate noun is kept in the general neuter form.