βουλητέον
From LSJ
ἐν δὲ τοῖς φυσικοῖς ἀεὶ οὕτως, ἂν μή τι ἐμποδίσῃ → in natural products the sequence is invariable, if there is no impediment | now with that which is natural it is always thus if there is no impediment
Spanish (DGE)
hay que decidirse a μαθεῖν Anaximen.Rh.1420b23.