Plato, Laws 922b

ταῦτα δὲ δὴ μετὰ τὰ νῦν εἰρημένα ἀναγκαῖον ἁμῶς γέ πως τάξασθαι. τούτων δὲ ἀρχαὶ πάντων αἵ τε τῶν τελευτᾶν μελλόντων ἐπιθυμίαι τῆς διαθέσεως αἵ τε τῶν μηδὲν τὸ παράπαν διαθεμένων τύχαι· ἀναγκαῖον δὲ εἶπον, ὦ Κλεινία, βλέψας αὐτῶν πέρι πρός τε τὸ δύσκολον καὶ χαλεπόν. οὐδὲ γὰρ ἄτακτον δυνατόν ἐστʼ αὐτὸ ἐᾶν· πολλὰ γὰρ ἕκαστοι καὶ διάφορα ἀλλήλων καὶ ἐναντία τιθεῖντʼ ἂν τοῖς τε νόμοις καὶ τοῖς τῶν ζώντων ἤθεσιν καὶ τοῖς αὑτῶν τοῖς ἔμπροσθεν

All these have their starting-points either in the desire of those at the point of death to devise their property, or in the accidental cases of those who die without making a testament; and it was in view of the complex and difficult nature of these cases, Clinias, that I made use of the word necessarily. And it is, indeed, impossible to leave them without regulation; for individuals might set down many wishes both at variance with one another and contrary to the laws as well as to the dispositions of the living, and also to their own former dispositions in the days before they proposed making a will,