§2#2Ἐπεὶ δὲ τρόποι πλείους τῆς αἰτίας (καὶ γὰρ τὸ τίνος ἕνεκα, καὶ ὅθεν ἡ ἀρχὴ τῆς κινήσεως, καὶ τὴν ὕλην καὶ τὸν λόγον αἴτιον εἶναί φαμεν), πρῶτον μὲν οὖν ἐπειδὴ λέγομεν τὴν φύσιν ἕνεκά του ποιεῖν, τοῦτο δ’ ἀγαθόν τι, τὴν δ’ ἀνάπαυσιν παντὶ τῷ πεφυκότι κινεῖσθαι, μὴ δυναμένῳ δ’ ἀεὶ καὶ συνεχῶς κινεῖσθαι μεθ’ ἡδονῆς ἀναγκαῖον εἶναι καὶ ὠφέλιμον, τῷ δ’ ὕπνῳ δι’ αὐτὴν τὴν ἀλήθειαν προσάπτουσι τὴν μεταφορὰν ταύτην ὡς ἀναπαύσει ὄντι· ὥστε σωτηρίας ἕνεκα τῶν ζῴων ὑπάρχει.
Since there are several ways of cause (for we say that the end, that from which the source of motion comes, the matter, and the definition are causes), first of all, since we say that nature acts for the sake of something, and this is some good, and that for everything whose nature is to move, but which cannot move always and continuously with pleasure, rest is necessary and beneficial, they apply this metaphor to sleep on account of the truth itself, as being a rest; so that it exists for the sake of the preservation of animals.
Ἡ δ’ ἐγρήγορσις τέλος· τὸ γὰρ αἰσθάνεσθαι καὶ τὸ φρονεῖν πᾶσι τέλος οἷς ὑπάρχει θάτερον αὐτῶν· βέλτιστα γὰρ ταῦτα, τὸ δὲ τέλος βέλτιστον.
But waking is the end; for perceiving and thinking are the end for all those in which either of them belongs; for these are best, and the end is the best.
Ὥστε ἀναγκαῖον ἑκάστῳ τῶν ζῴων ὑπάρχειν τὸν ὕπνον.
So that it is necessary for sleep to belong to each of the animals.
Λέγω δ’ ἐξ ὑποθέσεως τὴν ἀνάγκην, ὅτι εἰ ζῷον ἔσται ἔχον τὴν αὑτοῦ φύσιν, ἐξ ἀνάγκης τιν’ ὑπάρχειν αὐτῷ δεῖ, καὶ τούτων ὑπαρχόντων ἕτερα ὑπάρχειν.
And I speak of necessity on hypothesis, that if there is to be an animal having its own nature, it must of necessity have certain things belonging to it, and, these belonging to it, others must belong.
Ἔτι δὲ ποίας κινήσεως καὶ πράξεως ἐν τοῖς σώμασι γιγνομένης συμβαίνει τό τε ἐγρηγορέναι καὶ τὸ καθεύδειν τοῖς ζῴοις, μετὰ ταῦτα λεκτέον.
Furthermore, what kind of motion and action taking place in their bodies causes waking and sleeping to happen to animals, must be said after this.
Τοῖς μὲν οὖν ἄλλοις ζῴοις καθάπερ τοῖς ἐναίμοις ὑποληπτέον εἶναι τὰ αἴτια τοῦ πάθους, ἢ ταὐτὰ ἢ τὰ ἀνάλογον, τοῖς δ’ ἐναίμοις ἅπερ τοῖς ἀνθρώποις· ὥστ’ ἐκ τούτων πάντα θεωρητέον.
Now, for the other animals, just as for the red-blooded ones, we must assume that the causes of the affection are either the same or analogous, and for the red-blooded ones the same as for humans; so that from these we must investigate all things.
Ὅτι μὲν οὖν ἡ τῆς αἰσθήσεως ἀρχὴ γίνεται ἀπὸ τοῦ αὐτοῦ μέρους τοῖς ζῴοις ἀφ’ οὗπερ καὶ ἡ τῆς κινήσεως, διώρισται πρότερον ἐν ἑτέροις.
That the source of perception arises from the same part in animals from which the source of motion also comes, has been determined before in other works.
Αὕτη δ’ ἐστὶ τριῶν διωρισμένων τόπων ὁ μέσος κεφαλῆς καὶ τῆς κάτω κοιλίας.
And this is the middle of three determined regions, that is, of the head and the lower belly.
Τοῖς μὲν οὖν ἐναίμοις τοῦτ’ ἐστὶ τὸ περὶ τὴν καρδίαν μέρος· πάντα γὰρ τὰ ἔναιμα καρδίαν ἔχει, καὶ ἡ ἀρχὴ τῆς κινήσεως καὶ τῆς αἰσθήσεως τῆς κυρίας ἐντεῦθέν ἐστιν.
For red-blooded animals, then, this is the region around the heart; for all red-blooded animals have a heart, and the source of motion and of the primary perception is from there.
Τῆς μὲν οὖν κινήσεως φανερὸν ὅτι καὶ ἡ τοῦ πνεύματος ἀρχὴ καὶ ὅλως ἡ τῆς καταψύξεώς ἐστιν ἐνταῦθα, καὶ τὸ ἀναπνεῖν τε καὶ τὸ ὑγρῷ καταψύχεσθαι πρός γε σωτηρίαν τοῦ ἐν τούτῳ τῷ μορίῳ θερμοῦ ἡ φύσις πεπόρικεν.
As for motion, it is clear that both the source of breath and generally that of cooling is there, and nature has provided both breathing and cooling by moisture for the preservation of the heat in this part.
Ῥηθήσεται δὲ περὶ αὐτῆς ὕστερον καθ’ αὑτήν.
But about it, it will be said later by itself.
Τοῖς δ’ ἀναίμοις καὶ τοῖς ἐντόμοις καὶ μὴ δεχομένοις πνεῦμα ἐν τῷ ἀνάλογον τὸ σύμφυτον πνεῦμα ἀναφυσώμενον καὶ συνιζάνον φαίνεται.
For bloodless animals and insects and those which do not receive breath, the connate breath is seen to expand and contract in the analogous part.
Δῆλον δὲ τοῦτο ἐπὶ τῶν ὁλοπτέρων, οἷον σφηκῶν καὶ μελισσῶν, καὶ ἐν ταῖς μυίαις καὶ ὅσα τοιαῦτα.
And this is clear in the case of the insects with undivided wings, such as wasps and bees, and in flies and whatever other such creatures.
Ἐπεὶ δὲ κινεῖν μέν τι ἢ ποιεῖν ἄνευ ἰσχύος ἀδύνατον, ἰσχὺν δὲ ποιεῖ ἡ τοῦ πνεύματος κάθεξις, τοῖς μὲν εἰσφερομένοις ἡ θύραθεν, τοῖς δὲ μὴ ἀναπνέουσιν ἡ σύμφυτος.
Since, however, it is impossible to move something or to act without strength, and strength is produced by the holding of breath, by the external breath for those that draw it in, and by the connate breath for those that do not breathe.
Διὸ καὶ βομβοῦντα φαίνεται τὰ πτερωτά, ὅταν κινῆται, τῇ τρίψει τοῦ πνεύματος προσπίπτοντος πρὸς τὸ ὑπόζωμα τῶν ὁλοπτέρων.
Wherefore also the winged creatures are seen to buzz when they move, by the friction of the breath striking against the waist-boundary of the insects with undivided wings.
Κινεῖται δὲ πᾶν αἰσθήσεώς τινος γινομένης, ἢ οἰκείας ἢ ἀλλοτρίας, ἐν τῷ πρώτῳ αἰσθητηρίῳ.
And everything moves when some perception, either internal or external, occurs in the primary sense-organ.
Εἰ δ’ ἐστὶν ὁ ὕπνος καὶ ἡ ἐγρήγορσις πάθη τοῦ μορίου τούτου, ἐν ᾧ μὲν τόπῳ καὶ ἐν ᾧ μορίῳ πρώτῳ γίνεται ὁ ὕπνος καὶ ἡ ἐγρήγορσις, φανερόν.
If, then, sleep and waking are affections of this part, in what region and in what primary part sleep and waking occur is clear.
Κινοῦνται δ’ ἔνιοι καθεύδοντες καὶ ποιοῦσι πολλὰ ἐγρηγορικά, οὐ μέντοι ἄνευ φαντάσματος καὶ αἰσθήσεώς τινος· τὸ γὰρ ἐνύπνιόν ἐστιν αἴσθημα τρόπον τινά.
And some people move while sleeping and do many things characteristic of waking, yet not without an image and some perception; for a dream is in a way a perception.
Λεκτέον δὲ περὶ αὐτῶν ὕστερον.
But about them it must be said later.
Διότι δὲ τὰ μὲν ἐνύπνια μνημονεύουσιν ἐγερθέντες, τὰς δ’ ἐγρηγορικὰς πράξεις οὐ μνημονεύουσιν, ἐν τοῖς προβληματικοῖς εἴρηται.
And why indeed they remember dreams when they wake up, but do not remember their waking-like actions, has been said in the Problems.