πειρῶ δὴ καὶ σύ, ὦ Λάχης, τὴν ἀνδρείαν οὕτως εἰπεῖν τίς οὖσα δύναμις ἡ αὐτὴ ἐν ἡδονῇ καὶ ἐν λύπῃ καὶ ἐν ἅπασιν οἷς νυνδὴ ἐλέγομεν αὐτὴν εἶναι, ἔπειτα ἀνδρεία κέκληται.
This δη… I would not have paid much attention to it since it looks like a regular usage with imperatives for the sake of urgency… the comments, however, say that it is inferential meaning ‘then’. Where do they get it from?
Another point: τίς οὖσα δύναμις ἡ αὐτὴ I think we should assume the omission of ἐστι here: try to say, being what kind of function, it remains the same in pleasure, pain, etc.