I know it means that the soul is capable of doing something similar to what was just described, but I don’t see exactly how the pieces go together.
ἡ ψυχὴ (the soul) is the subject. ὑπάρχει (normally “belongs to” in Aristotle) is the finite verb. I expected the verb to take a dative followed maybe by a relative pronoun — the soul belongs to the sort of thing that . . . — but that is not what follows. Where is the dative for the ὑπάρχει? And what are a participle (οὖσα) and two infinitives (δύνασθαι πάσχειν) doing in there?
I think I see that τοῦτο is an object of the πάσχειν and refers to what was under discussion. So: δύνασθαι πάσχειν τοῦτο = “able to experience this” = “able to be affected in this way.”
And δύνασθαι is an infinitive to complete the participle οὖσα. Right so far?
Are τοιαύτη οὖσα οἵα all feminine nominatives to agree with ἡ ψυχὴ. But how exactly do they all work together?
Do they all add up to mean not just “the soul is capable of being affected in this way,” but “the soul is the sort of thing (τοιαύτη) as to be (οὖσα οἵα) capable of being affected in this way”?