βλεπτέον
From LSJ
Ὥσπερ οἱ ἐρωτικοὶ ἀπὸ τῶν ἐν αἰσθήσει καλῶν ὁδῷ προϊόντες ἐπ' αὐτὴν καταντῶσι τὴν μίαν τῶν καλῶν πάντων καὶ νοητῶν ἀρχήν → Just as lovers systematically leave behind what is fair to sensation and attain the one true source of all that is fair and intelligible
English (LSJ)
A one must look, εἴς τι Pl.Lg.965d, Arist.APr.44a36, etc.
Greek (Liddell-Scott)
βλεπτέον: ῥημ. ἐπίθ., πρέπει τις νὰ ἴδῃ, νὰ ἀποβλέψῃ, εἴς τι Πλάτ. Νόμ. 965D.
Spanish (DGE)
hay que observar τί ποτ' ἔστιν εἰς ὃ β. Pl.Lg.965d, εἰς τὰ προειρημένα β. Arist.APr.44a36, cf. Plot.6.5.2.