Let us consider this question more precisely. Is there any self-existent fire? and do all those things which we call self-existent exist? or are only those things which we see, or in some way perceive through the bodily organs, truly existent, and nothing whatever besides them? And is all that which, we call an intelligible essence nothing at all, and only a name? Here is a question which we must not leave unexamined or undetermined, nor must we affirm too confidently that there can be no decision; neither must we interpolate in our present long discourse a digression equally long, but if it is possible to set forth a great principle in a few words, that is just what we want.

Thus I state my view:-If mind and true opinion are two distinct classes, then I say that there certainly are these self-existent ideas unperceived by sense, and apprehended only by the mind; if, however, as some say, true opinion differs in no respect from mind, then everything that we perceive through the body is to be regarded as most real and certain. But we must affirm that to be distinct, for they have a distinct origin and are of a different nature; the one is implanted in us by instruction, the other by persuasion; the one is always accompanied by true reason, the other is without reason; the one cannot be overcome by persuasion, but the other can: and lastly, every man may be said to share in true opinion, but mind is the attribute of the gods and of very few men. Wherefore also we must acknowledge that there is one kind of being which is always the same, uncreated and indestructible, never receiving anything into itself from without, nor itself going out to any other, but invisible and imperceptible by any sense, and of which the contemplation is granted to intelligence only. And there is another nature of the same name with it, and like to it, perceived by sense, created, always in motion, becoming in place and again vanishing out of place, which is apprehended by opinion and sense. And there is a third nature, which is space, and is eternal, and admits not of destruction and provides a home for all created things, and is apprehended without the help of sense, by a kind of spurious reason, and is hardly real; which we beholding as in a dream, say of all existence that it must of necessity be in some place and occupy a space, but that what is neither in heaven nor in earth has no existence. Of these and other things of the same kind, relating to the true and waking reality of nature, we have only this dreamlike sense, and we are unable to cast off sleep and determine the truth about them. For an image, since the reality, after which it is modelled, does not belong to it, and it exists ever as the fleeting shadow of some other, must be inferred to be in another [i.e. in space ], grasping existence in some way or other, or it could not be at all. But true and exact reason, vindicating the nature of true being, maintains that while two things [i.e. the image and space] are different they cannot exist one of them in the other and so be one and also two at the same time.

λόγῳ δὲ δὴ μᾶλλον τὸ τοιόνδε διοριζομένους περὶ αὐτῶν διασκεπτέον· ἆρα ἔστιν τι πῦρ αὐτὸ ἐφ΄ ἑαυτοῦ καὶ πάντα περὶ ὧν ἀεὶ λέγομεν οὕτως [51c] αὐτὰ καθ΄ αὑτὰ ὄντα ἕκαστα͵ ἢ ταῦτα ἅπερ καὶ βλέπομεν͵ ὅσα τε ἄλλα διὰ τοῦ σώματος αἰσθανόμεθα͵ μόνα ἐστὶν τοιαύτην ἔχοντα ἀλήθειαν͵ ἄλλα δὲ οὐκ ἔστι παρὰ ταῦτα οὐδαμῇ οὐδαμῶς͵ ἀλλὰ μάτην ἑκάστοτε εἶναί τί φαμεν εἶδος ἑκάστου νοητόν͵ τὸ δ΄ οὐδὲν ἄρ΄ ἦν πλὴν λόγος; οὔτε οὖν δὴ τὸ παρὸν ἄκριτον καὶ ἀδίκαστον ἀφέντα ἄξιον φάναι διισχυριζόμενον ἔχειν οὕτως͵ οὔτ΄ ἐπὶ λόγου μήκει πάρεργον ἄλλο μῆκος ἐπεμβλητέον· [51d] εἰ δέ τις ὅρος ὁρισθεὶς μέγας διὰ βραχέων φανείη͵ τοῦτο μάλιστα ἐγκαιριώτατον γένοιτ΄ ἄν.

ὧδε οὖν τήν γ΄ ἐμὴν αὐτὸς τίθεμαι ψῆφον. εἰ μὲν νοῦς καὶ δόξα ἀληθής ἐστον δύο γένη͵ παντάπασιν εἶναι καθ΄ αὑτὰ ταῦτα͵ ἀναίσθητα ὑφ΄ ἡμῶν εἴδη͵ νοούμενα μόνον· εἰ δ΄͵ ὥς τισιν φαίνεται͵ δόξα ἀληθὴς νοῦ διαφέρει τὸ μηδέν͵ πάνθ΄ ὁπόσ΄ αὖ διὰ τοῦ σώματος αἰσθανόμεθα θετέον βεβαιότατα. [51e] δύο δὴ λεκτέον ἐκείνω͵ διότι χωρὶς γεγόνατον ἀνομοίως τε ἔχετον. τὸ μὲν γὰρ αὐτῶν διὰ διδαχῆς͵ τὸ δ΄ ὑπὸ πειθοῦς ἡμῖν ἐγγίγνεται· καὶ τὸ μὲν ἀεὶ μετ΄ ἀληθοῦς λόγου͵ τὸ δὲ ἄλογον· καὶ τὸ μὲν ἀκίνητον πειθοῖ͵ τὸ δὲ μεταπειστόν· καὶ τοῦ μὲν πάντα ἄνδρα μετέχειν φατέον͵ νοῦ δὲ θεούς͵ ἀνθρώπων δὲ γένος βραχύ τι. [52a] τούτων δὲ οὕτως ἐχόντων ὁμολογητέον ἓν μὲν εἶναι τὸ κατὰ ταὐτὰ εἶδος ἔχον͵ ἀγέννητον καὶ ἀνώλεθρον͵ οὔτε εἰς ἑαυτὸ εἰσδεχόμενον ἄλλο ἄλλοθεν οὔτε αὐτὸ εἰς ἄλλο ποι ἰόν͵ ἀόρατον δὲ καὶ ἄλλως ἀναίσθητον͵ τοῦτο ὃ δὴ νόησις εἴληχεν ἐπισκοπεῖν· τὸ δὲ ὁμώνυμον ὅμοιόν τε ἐκείνῳ δεύτερον͵ αἰσθητόν͵ γεννητόν͵ πεφορημένον ἀεί͵ γιγνόμενόν τε ἔν τινι τόπῳ καὶ πάλιν ἐκεῖθεν ἀπολλύμενον͵ δόξῃ μετ΄ αἰσθήσεως περιληπτόν· τρίτον δὲ αὖ γένος ὂν τὸ τῆς χώρας ἀεί͵ φθορὰν οὐ προσδεχόμενον͵ [52b] ἕδραν δὲ παρέχον ὅσα ἔχει γένεσιν πᾶσιν͵ αὐτὸ δὲ μετ΄ ἀναισθησίας ἁπτὸν λογισμῷ τινι νόθῳ͵ μόγις πιστόν͵ πρὸς ὃ δὴ καὶ ὀνειροπολοῦμεν βλέποντες καί φαμεν ἀναγκαῖον εἶναί που τὸ ὂν ἅπαν ἔν τινι τόπῳ καὶ κατέχον χώραν τινά͵ τὸ δὲ μήτ΄ ἐν γῇ μήτε που κατ΄ οὐρανὸν οὐδὲν εἶναι. ταῦτα δὴ πάντα καὶ τούτων ἄλλα ἀδελφὰ καὶ περὶ τὴν ἄυπνον καὶ ἀληθῶς φύσιν ὑπάρχουσαν [52c] ὑπὸ ταύτης τῆς ὀνειρώξεως οὐ δυνατοὶ γιγνόμεθα ἐγερθέντες διοριζόμενοι τἀληθὲς λέγειν͵ ὡς εἰκόνι μέν͵ ἐπείπερ οὐδ΄ αὐτὸ τοῦτο ἐφ΄ ᾧ γέγονεν ἑαυτῆς ἐστιν͵ ἑτέρου δέ τινος ἀεὶ φέρεται φάντασμα͵ διὰ ταῦτα ἐν ἑτέρῳ προσήκει τινὶ γίγνεσθαι͵ οὐσίας ἁμωσγέπως ἀντεχομένην͵ ἢ μηδὲν τὸ παράπαν αὐτὴν εἶναι͵ τῷ δὲ ὄντως ὄντι βοηθὸς ὁ δι΄ ἀκριβείας ἀληθὴς λόγος͵ ὡς ἕως ἄν τι τὸ μὲν ἄλλο ᾖ͵ τὸ δὲ ἄλλο͵ οὐδέτερον ἐν οὐδετέρῳ ποτὲ γενόμενον ἓν ἅμα ταὐτὸν καὶ δύο γενήσεσθον.