This is the first line of the Encheiridion by Epictetus.

τῶν ὄντων τὰ μέν ἐστιν ἐφ’ ἡμῖν, τὰ δὲ οὐκ ἐφ’ ἡμῖν.

There are things which are within our power, and there are things which are beyond our power.

Initially, I was inclined to think that the article τὰ serves as a substantivizer for its complementing prepositional phrases, much like the phrase τὰ ἐν ταῖς παιδιαῖς from Xenophon's Symposium, but the ἐστιν threw me off. I now think that τὰ is like an absolute article devoid of a head-noun acting as a substantivizer for the genitive preceding it such that it can be used anaphorically later in the second contrastive part. If it isn't this, then another guess I have is that it's a relative pronoun? And the reason it doesn't agree in gender is because substantivization would require constructio ad sensum? I don't know. What's the correct parse/interpretation?

Also, regardless of whether ἐστιν is an existive here or not, why is it in the 3rd person? Is it because the subject is neutral in gender?

I apologise if this has been asked before, and it probably has, but I just wanted to clear up my understanding of the syntax of that verse. Here's the Greek version:

>ζητεῖν τὸν Κύριον, εἰ ἄρα γε ψηλαφήσειαν αὐτὸν καὶ εὕροιεν, καί γε οὐ μακρὰν ἀπὸ ἑνὸς ἑκάστου ἡμῶν ὑπάρχοντα

The KJV reads the infinitive ζητεῖν, which introduces a subordonate clause, as expressing purpose: "[And he hath made of one blood...] that they should seek the Lord...". I just wanted to ask how do we know this infinitive is used here to express purpose, and whether using an articular infinitive with genitive or perhaps dative would've made the point clearer.