Apparitions show the soul survives
Then, as though this could happen, I mean that someone has an apparition of a dead man as if he were alive, he goes on like an Epicurean and says that “someone dreamed in a certain state of mind, or by his own wish had an illusion through mistaken belief, and reported such a thing; which,” he says, “has already happened to countless people.”
Even if this seemed to have been said with great cleverness, it nonetheless establishes a necessary doctrine: that the soul of the dead does subsist, and that whoever has taken up this doctrine has not believed in vain in its immortality, or at least in its survival; as Plato too, in his work on the soul, says that “shadowy apparitions” of people already dead have appeared to some around tombs (Plato, Phaedo 81d). Now the “apparitions” that occur concerning the soul of the dead arise from something that underlies them: the soul that subsists in what is called the luminous body.
But Celsus, not wanting this, would have it that some people dream even while awake and, according to their own wish, have illusions through mistaken belief. To believe that this happens in sleep is not unreasonable; but that it happens while awake, to those who are not wholly out of their minds and delirious, or melancholic, is not credible. Foreseeing this, Celsus said the woman was frenzied, though the written account, from which he draws the material for his charges against the events, does not show this.
Greek
Εἶτα ὡς δυναμένου τούτου συμβῆναι, λέγω δὴ τοῦ φαντασίαν τινὶ γίνεσθαι περὶ τοῦ τεθνηκότος ὡς ζῶντος. ἐπιφέρει ὡς Ἐπικούρειος καὶ λέγει κατά τινα διάθεσιν ὀνειρώξαντά τινα ἢ κατὰ τὴν αὐτοῦ βούλησιν δόξῃ πεπλανημένῃ φαντασιωθέντα τὸ τοιοῦτον ἀπηγγελκέναι. ὅπερ. φησὶ. μυρίοις ἤδη συμβέβηκε. τοῦτο δὲ εἰ καὶ δεινότατα ἔδοξεν εἰρῆσθαι. οὐδὲν ἧττον κατασκευαστικόν ἐστιν ἀναγκαίου δόγματος. ὡς ἄρα ἡ ψυχὴ ὑφέστηκε τῶν ἀποθανόντων· καὶ οὐ μάτην πεπίστευκε περὶ τῆς ἀθανασίας αὐτῆς ἢ κἂν τῆς διαμονῆς ὁ τοῦτο τὸ δόγμα ἀνειληφώς· ὡς καὶ Πλάτων ἐν τῷ περὶ τῆς ψυχῆς λέγει „σκιοειδῆ φαντάσματα“ περὶ μνημεῖά τισι γεγονέναι τῶν ἤδη τεθνηκότων. τὰ μὲν οὖν γινόμενα περὶ ψυχῆς τεθνηκότων „φαντάσματα“ ἀπό τινος ὑποκειμένου γίνεται. τοῦ κατὰ τὴν ὑφεστηκυῖαν ἐν τῷ καλουμένῳ αὐγοειδεῖ σώματι ψυχήν. ὁ δὲ Κέλσος οὐ βουλόμενος τὸ τοιοῦτον θέλει καὶ ὕπαρ ὀνειρώττειν τινὰς καὶ κατὰ τὴν ἑαυτῶν βούλησιν δόξῃ πεπλανημένῃ φαντασιοῦσθαι· ὅπερ ὄναρ μὲν πιστεύειν γίνεσθαι οὐκ ἄλογον. ὕπαρ δὲ ἐπὶ τῶν μὴ πάντῃ ἐκφρόνων καὶ φρενιτιζόντων ἢ μελαγχολώντων οὐ πιθανόν. καὶ τοῦτο δὲ προειδόμενος ὁ Κέλσος παροιστρῶσαν εἶπε τὴν γυναῖκα· ὅπερ οὐκ ἐμφαίνει ἡ ἀναγραφεῖσα ἱστορία, ὅθεν λαβὼν κατηγορεῖ τῶν πραγμάτων.