HAVE thus shown the various classes of bodies as they are diversified by their forms and combinations and changes into one another, and now I must endeavour to set forth their affections and the causes of them. In the first place, the bodies which I have been describing are necessarily objects of sense. But we have not yet considered the origin of flesh, or what belongs to flesh, or of that part of the soul which is mortal. And these things cannot be adequately explained without also explaining the affections which are concerned with sensation, nor the latter without the former: and yet to explain them together is hardly possible; for which reason we must assume first one or the other and afterwards examine the nature of our hypothesis. In order, then, that the affections may follow regularly after the elements, let us presuppose the existence of body and soul.

First, let us enquire what we mean by saying that fire is hot; and about this we may reason from the dividing or cutting power which it exercises on our bodies. We all of us feel that fire is sharp; and we may further consider the fineness of the sides, and the sharpness of the angles, and the smallness of the particles, and the swiftness of the motion-all this makes the action of fire violent and sharp, so that it cuts whatever it meets. And we must not forget that the original figure of fire [i.e. the pyramid], more than any other form, has a dividing power which cuts our bodies into small pieces (Kepmatizei), and thus naturally produces that affection which we call heat; and hence the origin of the name (thepmos, Kepma). Now, the opposite of this is sufficiently manifest; nevertheless we will not fail to describe it. For the larger particles of moisture which surround the body, entering in and driving out the lesser, but not being able to take their places, compress the moist principle in us; and this from being unequal and disturbed, is forced by them into a state of rest, which is due to equability and compression.

αἰσθήσεις

Καὶ τὰ μὲν δὴ σχήμασι κοινωνίαις τε καὶ μεταλλαγαῖς εἰς ἄλληλα πεποικιλμένα εἴδη σχεδὸν ἐπιδέδεικται· τὰ δὲ παθήματα αὐτῶν δι΄ ἃς αἰτίας γέγονεν πειρατέον ἐμφανίζειν. πρῶτον μὲν οὖν ὑπάρχειν αἴσθησιν δεῖ τοῖς λεγομένοις ἀεί͵ σαρκὸς δὲ καὶ τῶν περὶ σάρκα γένεσιν͵ ψυχῆς τε ὅσον θνητόν͵ οὔπω διεληλύθαμεν· [61d] τυγχάνει δὲ οὔτε ταῦτα χωρὶς τῶν περὶ τὰ παθήματα ὅσα αἰσθητικὰ οὔτ΄ ἐκεῖνα ἄνευ τούτων δυνατὰ ἱκανῶς λεχθῆναι͵ τὸ δὲ ἅμα σχεδὸν οὐ δυνατόν. ὑποθετέον δὴ πρότερον θάτερα͵ τὰ δ΄ ὑποτεθέντα ἐπάνιμεν αὖθις. ἵνα οὖν ἑξῆς τὰ παθήματα λέγηται τοῖς γένεσιν͵ ἔστω πρότερα ἡμῖν τὰ περὶ σῶμα καὶ ψυχὴν ὄντα.  

πρῶτον μὲν οὖν ᾗ πῦρ θερμὸν λέγομεν͵ ἴδωμεν ὧδε σκοποῦντες͵ τὴν διάκρισιν καὶ τομὴν αὐτοῦ περὶ τὸ σῶμα ἡμῶν γιγνομένην ἐννοηθέντες. [61e] ὅτι μὲν γὰρ ὀξύ τι τὸ πάθος͵ πάντες σχεδὸν αἰσθανόμεθα· τὴν δὲ λεπτότητα τῶν πλευρῶν καὶ γωνιῶν ὀξύτητα τῶν τε μορίων σμικρότητα καὶ τῆς φορᾶς τὸ τάχος͵ οἷς πᾶσι σφοδρὸν ὂν καὶ τομὸν ὀξέως τὸ προστυχὸν ἀεὶ τέμνει͵ [62a] λογιστέον ἀναμιμνῃσκομένοις τὴν τοῦ σχήματος αὐτοῦ γένεσιν͵ ὅτι μάλιστα ἐκείνη καὶ οὐκ ἄλλη φύσις διακρίνουσα ἡμῶν κατὰ σμικρά τε τὰ σώματα κερματίζουσα τοῦτο ὃ νῦν θερμὸν λέγομεν εἰκότως τὸ πάθημα καὶ τοὔνομα παρέσχεν. τὸ δ΄ ἐναντίον τούτων κατάδηλον μέν͵ ὅμως δὲ μηδὲν ἐπιδεὲς ἔστω λόγου. τὰ γὰρ δὴ τῶν περὶ τὸ σῶμα ὑγρῶν μεγαλομερέστερα εἰσιόντα͵ τὰ σμικρότερα ἐξωθοῦντα͵ εἰς τὰς ἐκείνων οὐ δυνάμενα ἕδρας ἐνδῦναι͵ συνωθοῦντα ἡμῶν τὸ νοτερόν͵ [62b] ἐξ ἀνωμάλου κεκινημένου τε ἀκίνητον δι΄ ὁμαλότητα καὶ τὴν σύνωσιν ἀπεργαζόμενα πήγνυσιν·