In the first place, we see that what we just now called water, by condensation, I suppose, becomes stone and earth; and this same element, when melted and dispersed, passes into vapour and air. Air, again, when inflamed, becomes fire; and again fire, when condensed and extinguished, passes once more into the form of air; and once more, air, when collected and condensed, produces cloud and mist; and from these, when still more compressed, comes flowing water, and from water comes earth and stones once more; and thus generation appears to be transmitted from one to the other in a circle. Thus, then, as the several elements never present themselves in the same form, how can any one have the assurance to assert positively that any of them, whatever it may be, is one thing rather than another? No one can. But much the safest plan is to speak of them as follows:-Anything which we see to be continually changing, as, for example, fire, we must not call "this" or "that," but rather say that it is "of such a nature"; nor let us speak of water as "this"; but always as "such"; nor must we imply that there is any stability in any of those things which we indicate by the use of the words "this" and "that," supposing ourselves to signify something thereby; for they are too volatile to be detained in any such expressions as "this," or "that," or "relative to this," or any other mode of speaking which represents them as permanent. We ought not to apply "this" to any of them, but rather the word "such"; which expresses the similar principle circulating in each and all of them; for example, that should be called "fire" which is of such a nature always, and so of everything that has generation. That in which the elements severally grow up, and appear, and decay, is alone to be called by the name "this" or "that"; but that which is of a certain nature, hot or white, or anything which admits of opposite equalities, and all things that are compounded of them, ought not to be so denominated. Let me make another attempt to explain my meaning more clearly.

πρῶτον μέν͵ ὃ δὴ νῦν ὕδωρ ὠνομάκαμεν͵ πηγνύμενον ὡς δοκοῦμεν λίθους καὶ γῆν γιγνόμενον ὁρῶμεν͵ [49c] τηκόμενον δὲ καὶ διακρινόμενον αὖ ταὐτὸν τοῦτο πνεῦμα καὶ ἀέρα͵ συγκαυθέντα δὲ ἀέρα πῦρ͵ ἀνάπαλιν δὲ συγκριθὲν καὶ κατασβεσθὲν εἰς ἰδέαν τε ἀπιὸν αὖθις ἀέρος πῦρ͵ καὶ πάλιν ἀέρα συνιόντα καὶ πυκνούμενον νέφος καὶ ὁμίχλην͵ ἐκ δὲ τούτων ἔτι μᾶλλον συμπιλουμένων ῥέον ὕδωρ͵ ἐξ ὕδατος δὲ γῆν καὶ λίθους αὖθις͵ κύκλον τε οὕτω διαδιδόντα εἰς ἄλληλα͵ ὡς φαίνεται͵ τὴν γένεσιν. [49d] οὕτω δὴ τούτων οὐδέποτε τῶν αὐτῶν ἑκάστων φανταζομένων͵ ποῖον αὐτῶν ὡς ὂν ὁτιοῦν τοῦτο καὶ οὐκ ἄλλο παγίως διισχυριζόμενος οὐκ αἰσχυνεῖταί τις ἑαυτόν; οὐκ ἔστιν͵ ἀλλ΄ ἀσφαλέστατα μακρῷ περὶ τούτων τιθεμένους ὧδε λέγειν· ἀεὶ ὃ καθορῶμεν ἄλλοτε ἄλλῃ γιγνόμενον͵ ὡς πῦρ͵ μὴ τοῦτο ἀλλὰ τὸ τοιοῦτον ἑκάστοτε προσαγορεύειν πῦρ͵ μηδὲ ὕδωρ τοῦτο ἀλλὰ τὸ τοιοῦτον ἀεί͵ μηδὲ ἄλλο ποτὲ μηδὲν ὥς τινα ἔχον βεβαιότητα͵ [49e] ὅσα δεικνύντες τῷ ῥήματι τῷ τόδε καὶ τοῦτο προσχρώμενοι δηλοῦν ἡγούμεθά τι· φεύγει γὰρ οὐχ ὑπομένον τὴν τοῦ τόδε καὶ τοῦτο καὶ τὴν τῷδε καὶ πᾶσαν ὅση μόνιμα ὡς ὄντα αὐτὰ ἐνδείκνυται φάσις. ἀλλὰ ταῦτα μὲν ἕκαστα μὴ λέγειν͵ τὸ δὲ τοιοῦτον ἀεὶ περιφερόμενον ὅμοιον ἑκάστου πέρι καὶ συμπάντων οὕτω καλεῖν͵ καὶ δὴ καὶ πῦρ τὸ διὰ παντὸς τοιοῦτον͵ καὶ ἅπαν ὅσονπερ ἂν ἔχῃ γένεσιν· ἐν ᾧ δὲ ἐγγιγνόμενα ἀεὶ ἕκαστα αὐτῶν φαντάζεται καὶ πάλιν ἐκεῖθεν ἀπόλλυται͵ [50a] μόνον ἐκεῖνο αὖ προσαγορεύειν τῷ τε τοῦτο καὶ τῷ τόδε προσχρωμένους ὀνόματι͵ τὸ δὲ ὁποιονοῦν τι͵ θερμὸν ἢ λευκὸν ἢ καὶ ὁτιοῦν τῶν ἐναντίων͵ καὶ πάνθ΄ ὅσα ἐκ τούτων͵ μηδὲν ἐκεῖνο αὖ τούτων καλεῖν. ἔτι δὲ σαφέστερον αὐτοῦ πέρι προθυμητέον αὖθις εἰπεῖν.