I'm writing a paper on Michael of Ephesus on providence. I've looked at his views on providence before, but I've started to take it a bit more seriously. Michael uses providence in a few places in his commentaries on Aristotle's biology, and he uses it, as you might expect, as a deus (natura?) ex machina to explain things Aristotle does not (maybe it's more precise to say that he uses providence to complete explanations which Aristotle had left incomplete). On the one hand, I'm interested in in figuring out what Michael thinks providence is - is it a version of the Christian God, or nature, or νοῦς? - but I'm also trying to figure out what his rules are for using it in his commentaries. The way he uses it doesn't seem to be arbitrary (there are times he doesn't use it when he could) and this makes me wonder if he's drawing on an earlier tradition, or following his own philosophical or cultural intuitions. Here is one of these appeals, about why some animals have testes and some do not. NB: I think the fact that Michael refers to providence in this passage should not distract us from what he is actually trying to do, and that is to explain animal mating behaviour in terms of the contribution the behaviour makes to the survival of the species. Also: contrary to what Aristotle and Michael say, fish and snakes do in fact have testes.
Aristotle: "Nature does everything because of necessity of because of the better..."
"If nature does everything either because of necessity or because of the better, then this part [i.e., the testicles] would also exist for one of these reasons. Now, that testicles are not necessary for generation is obvious, since then all animals that generate would have them; but in fact, snakes, birds, and fish do not have testicles, for they are observed when they are mating and they have ducts filled with milt. It remains, then, that they are present for something better. It is a fact that, for most animals, there is just about no other function than [producing] seed and fruit, as is the case for plants. And just as in matters of nutrition animals with straight intestines are more ravenous* in their desire for food, so too those that do not have testicles but only ducts, or which have testicles but have them internally, they are all quicker with respect to the activity of mating. Those animals which need to be more moderate**, just as before the intestines are not straight, also here the ducts have coils so that their desire is not either ravenous or sudden.*** Testicles have been designed for this reason, for they make the movement of the spermatic residue slower."****
εἰ δὴ πᾶν ἡ φύσις ἢ διὰ τὸ ἀναγκαῖον ποιεῖ ἢ διὰ τὸ βέλτιον, κἂν τοῦτο τὸ μόριον εἴη διὰ τούτων θάτερον. ὅτι μὲν τοίνυν οὐκ ἀναγκαῖον πρὸς τὴν γένεσιν φανερόν· πᾶσι γὰρ ἂν ὑπῆρχε τοῖς γεννῶσι, νῦν δ' οὔθ' οἱ ὄφεις ἔχουσιν ὄρχεις οὔθ' οἱ ἰχθύες· ὠμμένοι γάρ εἰσι συνδυαζόμενοι καὶ πλήρεις ἔχοντες θοροῦ τοὺς πόρους. λείπεται τοίνυν βελτίονός τινος χάριν. ἔστι δὲ τῶν μὲν πλείστων ζῴων ἔργον σχεδὸν οὐθὲν ἄλλο πλὴν ὥσπερ τῶν φυτῶν σπέρμα καὶ καρπός. ὥσπερ δ' ἐν τοῖς περὶ τὴν τροφὴν τὰ εὐθυέντερα λαβρότερα πρὸς τὴν ἐπιθυμίαν τὴν τῆς τροφῆς, οὕτω καὶ τὰ μὴ ἔχοντα ὄρχεις πόρους δὲ μόνον ἢ ἔχοντα μὲν ἐντὸς δ' ἔχοντα, πάντα ταχύτερα πρὸς τὴν ἐνέργειαν τῶν συνδυασμῶν. ἃ δὲ δεῖ σωφρονέστερα εἶναι, ὥσπερ ἐκεῖ οὐκ εὐθυέντερα, καὶ ἐνταῦθ' ἕλικας ἔχουσιν οἱ πόροι πρὸς τὸ μὴ λάβρον μηδὲ ταχεῖαν εἶναι τὴν ἐπιθυμίαν. οἱ δ' ὄρχεις εἰσὶ πρὸς τοῦτο μεμηχανημένοι· τοῦ γὰρ σπερματικοῦ περιττώματος στασιμωτέραν ποιοῦσι τὴν κίνησιν.
Aristotle, Generation of Animals 1.4, 717a12-32 (Peck's Loeb edition here)
* λαβρότερα | 'more ravenous' The word λάβρος can describe violent surges of water and wind, also people and animals. LSJ suggest 'furious' or 'violent', or 'impetuous'; Peck translates it as 'violent'. The sense, however, is clearly that the animals have strong appetites: their intestines are shorter, and without twists and turns to slow down the food and residues, they are never full for long. I like 'ravenous' here: we use it in English (although it is a bit affected) to describe strong appetites + 'ravenous' comes from the archaic ravin ('an act of rapine or robbery'), which is a direct borrowing from French ravine ('impetuosity', violence', 'force'), from which we get ravine, i.e., 'a violent rush of water' and by extension the gorge it travels through. From the Latin rapina, 'to rob', 'plunder', etc. In the Michael passage, I translate it as "(more) impulsive".
** δεῖ σωφρονέστερα | 'need to be more moderate' More of a moral term than λάβρος. Peck translates 'have to be more sober'. But it's the δεῖ that's caused people to pause: why do some animals need to be more moderate in their appetites? Why couldn't all animals be ravenous and impetuous? Aristotle does not tell us why; he just mentions that testicles cause the seminal ducts to double back, 'like stone weights on a loom (a35-6: καθάπερ τὰς λαιὰς προσάπτουσιν αἱ ὑφαίνουσαι τοῖς ἱστοῖς)'.
*** πρὸς τὸ μὴ λάβρον μηδὲ ταχεῖαν εἶναι τὴν ἐπιθυμίαν This is a statement of the final cause - testiclescause the ducts to coil in order to steady the animal's desire. The relationship between desire and lack or excess might be in the background: desire for food is an impulse to fill something that has been emptied beyond what is natural; and the desire for sex is an impulse to empty something that has been filled to excess. However, if this were the case, it's not clear to me why slower moving semen would cause an animal to have less desire. Aristotle is vague about the details of the analogy, and Michael will focus mostly on trying to make sense of it.
**** στασιμωτέραν ποιοῦσι τὴν κίνησιν Peck translates 'makes the motion steadier'. στάσιμος is an absence of κίνσις, i.e., movement as flow (e.g. Plato, Sophist 256b6-7; Hippocrates, Nature of Women 1.10). Potter translates it as 'constipated' in his Loeb translation of Nature of Women. The idea again is that the residues don't flow out as quickly as they would if the ducts were straight.
Michael on Aristotle on pudic providence
"What comes to be by nature, comes to be by necessity or the better. "Necessity" means that which is found in every kind, and without which it is not possible for something to come to be. "Better" [means] that which is not like this. Since testicles are not found in every [kind] of male, and generation also occurs without them, they do not exist because of necessity, but because of the better.
Just as, in matters of nutrition, [animals] with straight intestines are more ravenous…
"In what follows he sets out the reasons because of which, among [animals] that have testicles and do not have testicles, (i) some have them, (ii) others do not have them; and of those that have them, (i.b) some have them internally, like birds, but (i.a) others externally. He says, then, that just as "animals with straight intestines" are "more impulsive with respect to desire for food", because the residue comes out more quickly because of their straight intestines, while those that do not have straight intestines are more self-controlled and take less nourishment, "the same applies to (ii) [animals] that do not have testicles but only passages", like fish, "or (i.b) [animals] that have [testicles] but internally", like birds. Hence, (ii) [animals] that do not have testicles at all are quicker than all other [animals] with respect to the task of mating; (i.b) while [animals] that have [testicles] internally are slower and more self-controlled with respect to this kind of task than those that do not have testicles, but they are more impulsive and faster than (i.a) the ones that have them externally.
"First, we should say why [nature] has designed some [animals] to be naturally self-controlled and has made the testicles of these kinds external, some [naturally] more impulsive and [made their testicles] internal, but others it has utterly neglected and did not assign testicles, and for this reason they are also most impulsive of all. But on this point we should say briefly that [nature] did not neglect them, but that it has regarded them by an even greater magnitude. For since (as he will say going on) they are not able to engage in contact for a long time because they live in water, [nature] has not given [them] testicles in addition to the other things (which he is going to speak about later). For in the case of animals that have testicles, the emission of semen comes about slowly because of the reasons which we will learn. But let this much have been said as an introduction. We must discuss what was mentioned, and then the cause according to which (i.a) firstly, those that have external testicles are especially self-controlled, (i.b) second those [that have] internal [testicles] are even less so, and (ii) most undisciplined of all are those that do not have any [testicles]. And so, we must move on to Aristotle's answer.
"One should note that since nature desires that animals and all other things exist eternally and aims at this, whatever things were not able to be preserved eternally as the same thing numerically, for them [nature] decreed eternity by means of always generating others from others. But since continuous mating causes dissolution of the body* for reasons he will mention in the present book when he talks about what the nature of semen is—since then [continuous mating] imparts weakness, and it is normal for death to follow dissolution in the majority of cases, all those animals that naturally bear few offspring (he will also talk about the reasons for their bearing few young in the present book and in those that follow this one)—all those, then, that naturally bear few offspring have come to be more self-controlled than the others by nature's forethought, so that the animals are not dissolved and destroyed by mating many times each day, and this kind of animal is not suddenly eradicated. Those animals that bear offspring, but [bear] more than those that bear few and a fewer number than those that bear very many, are less moderately self-controlled than those that bear few offspring. For even though they [i.e., the individual animals] should happen to be destroyed from frequent mating, still, because of the fact that they bear more than two or three offspring (it is sometimes possible [for them to bear] even more than seventeen**), such a kind will not be left out of the whole. For this reason, then, [nature] designed these to be less self-controlled. But those that bear altogether many offspring, what necessity is there to regard them? For it is clear that they will not be lacking, since heaps of them are produced. This, then, is the reason that some are more self-controlled, others less, and others not at all."
τὰ δὲ ὑπὸ τῆς φύσεως γινόμενα τὰ μὲν γίνεται διὰ τὸ ἀναγκαῖον, τὰ δὲ διὰ τὸ βέλτιον. ἀναγκαῖον δὲ λέγεται τὸ ἐν ἅπαντι τῷ γένει εὑρισκόμενον, καὶ οὗ ἄνευ οὐκ ἐνδέχεται γενέσθαι τι, βέλτιον δὲ τὸ μὴ τοιοῦτον. ἐπεὶ δὲ οἱ ὄρχεις οὔτε ἐν ἅπαντι τῷ τῶν ἀρρένων εὑρίσκονται γένει, γίνεται δὲ γένεσις καὶ χωρὶς αὐτῶν, οὔκ εἰσι διὰ τὸ ἀναγκαῖον, ἀλλὰ διὰ τὸ βέλτιον.
 717a23 «Ὥσπερ δὲ ἐν τοῖς περὶ τροφὴν τὰ εὐθυέντερα λαβρότερα.»
Ἐντεῦθεν τὰς αἰτίας ἐκτίθεται, δι' ἃς τὰ ἔχοντα ὄρχεις καὶ τὰ μὴ [6.1] ἔχοντα τὰ μὲν ἔχει, τὰ δ' οὐκ ἔχει, καὶ τῶν ἐχόντων τὰ μὲν ἐντὸς ἔχει, ὥσπερ οἱ ὄρνιθες, τὰ δ' ἐκτός. φησὶν οὖν ὅτι, ὥσπερ «τὰ εὐθυέντερα λαβρότερά» ἐστι «πρὸς τὴν ἐπιθυμίαν τῆς τροφῆς» διὰ τὸ θᾶττον ἐξέρχεσθαι τὸ περίττωμα διὰ τὴν εὐθυεντερίαν, τὰ δὲ μὴ εὐθυέντερα σωφρονέστερα καὶ  ὀλιγοτροφώτερα, «οὕτω καὶ τὰ μὴ ἔχοντα ὄρχεις, πόρους δὲ μόνον», ὡς οἱ ἰχθύες, «ἢ ἔχοντα μὲν ἐντὸς δέ» [717a23-25], ὡς οἱ ὄρνιθες· τὰ μὲν οὖν μηδ' ὅλως ἔχοντα ὄρχεις εἰσὶ πρὸς τὴν ἐργασίαν τοῦ συνδυασμοῦ ταχύτερα πάντων, τὰ δ' ἔχοντα μὲν ἐντὸς δὲ βραδύτερα πρὸς τὴν τοιαύτην ἐργασίαν τῶν μὴ ἐχόντων ὄρχεις καὶ σωφρονέστερα, λαβρότερα δὲ καὶ ταχύτερα τῶν αὐτοὺς  ἐχόντων ἐκτός.
ῥητέον δ' οὖν ἡμῖν πρῶτον μέν, τίνος ἕνεκεν τῇ φύσει πεφρόντισται τοῦ τὰ μὲν εἶναι σώφρονα καὶ πεποίηκε τῶν τοιούτων τοὺς ὄρχεις ἐκτός, τὰ δὲ λαβρότερα καὶ ἐντός, τῶν δὲ καὶ παντελῶς κατωλιγώρηκε καὶ οὐκ ἀπέδωκεν ὄρχεις, καὶ διὰ τοῦτό εἰσι καὶ πάντων λαβρότατα. ῥητέον δὲ πρὸς τοῦτο συντόμως ὅτι οὐδὲ τούτων κατωλιγώρησεν, ἀλλὰ καὶ  μᾶλλον κατὰ πολὺ πεφρόντικεν· ἐπειδὴ γὰρ ἐν ὕδατι ὄντα οὐ δύνανται ἐπὶ πολὺ ἐνδιατρίβειν, ὡς καὶ αὐτὸς προϊὼν ἐρεῖ, τῇ ἁφῇ, οὐ δέδωκε πρὸς τοῖς ἄλλοις οἷς μέλλει λέγειν λόγοις περὶ τούτων ὄρχεις· ἐν γὰρ τοῖς ἔχουσιν ὄρχεις βραδεῖα δι' ἃς μαθησόμεθα αἰτίας ἡ πρόεσις τοῦ σπέρματος γίνεται. ἀλλὰ τοῦτο μὲν οὕτως προλελέχθω· ἡμῖν δὲ τὰ εἰρημένα ῥητέον καὶ ἔτι  τὴν αἰτίαν καθ' ἣν συμβαίνει πρώτως καὶ μάλιστα σώφρονα εἶναι τὰ ἐκτὸς ἔχοντα τοὺς ὄρχεις, δευτέρως δὲ καὶ ἧττον τὰ ἐντός, πάντων δὲ ἀκολαστότατα τὰ μηδ' ὅλως τούτους ἔχοντα· καὶ οὕτως τὴν Ἀριστοτέλους ῥῆσιν μετιτέον.
ἰστέον οὖν ὡς ἐπειδὴ ἡ φύσις τοῦ ἀεὶ εἶναι ζῷα καὶ τὰ ἄλλα πάντα ἐφίεται καὶ τούτου στοχάζεται, ὅσα οὐκ ἠδυνήθη φυλάξαι ἀεὶ τὰ  αὐτὰ τῷ ἀριθμῷ, τούτοις ἐπρυτάνευσε τὴν ἀιδιότητα διὰ τοῦ ἀεὶ ἄλλα ἐξ ἄλλων γίνεσθαι. ἀλλ' ἐπεὶ ὁ συνδυασμὸς ὁ συνεχὴς ἔκλυσιν τοῦ σώματος ἐμποιεῖ δι' ἃς ἐρεῖ αἰτίας ἐν τῷ παρόντι βιβλίῳ, ὅταν περὶ τῆς φύσεως τοῦ σπέρματος λέγῃ τίς ἐστιν, ἐπεὶ οὖν ἔκλυσιν ἐμποιεῖ, τῇ ἐκλύσει δὲ φιλεῖ ὡς τὰ πολλὰ παρέπεσθαι θάνατον, ὅσα τῶν ζῴων ὀλιγοτόκα πέφυκεν  (ἐρεῖ δὲ καὶ τῆς τούτων ὀλιγοτοκίας τὰς αἰτίας ἐν τῷ παρόντι βιβλίῳ καὶ ἐν τοῖς ἐφεξῆς τούτου) ὅσα οὖν πέφυκεν ὀλιγοτόκα, γέγονε σωφρονέστερα τῶν ἄλλων προνοίᾳ φύσεως, ὅπως μὴ πολλάκις τῆς ἡμέρας συνδυαζόμενα ἐκλύηται καὶ φθείρηται καὶ τάχιον ἐκποδὼν γένηται τὸ τοιοῦτον γένος. ὅσα δὲ τίκτει μέν, ἀλλὰ πλείω μὲν τῶν ὀλιγοτόκων, ἐλάττω δὲ κατὰ πολὺ  τῶν πάνυ πολλὰ τικτόντων, ἧττόν ἐστι σωφρονέστερα τῶν ὀλιγοτόκων· εἰ γὰρ καὶ συμβαίη αὐτοῖς φθορὰ ἐκ τοῦ πολλάκις συνδυάζεσθαι, ἀλλὰ διὰ τὸ [7.1] πλείω τοῖν δυοῖν καὶ τριῶν τίκτειν, ἔστι δ' ὅτε καὶ τῶν ἑπτὰ καὶ δέκα, οὐκ ἐπιλείψει τὸ τοιοῦτον γένος ἐκ τοῦ παντός. διὰ τοῦτο οὖν ἧττον ἐφρόντισε τοῦ σώφρονα εἶναι ταῦτα. τῶν δὲ πάμπαν πολλὰ τικτόντων τίς ἡ ἀνάγκη τούτων φροντίσαι; δῆλον γὰρ ὡς οὐκ ἐπιλείψουσι σωρηδὸν γινόμενα. ἡ μὲν οὖν αἰτία τοῦ τὰ μὲν εἶναι σώφρονα μᾶλλον τὰ δ' ἧττον τὰ δ' οὐδ' ὅλως αὕτη.
Michael of Ephesus, In de generatione animalium commentaria 1.4 (CAG 14.3, 5,35-7,6 Hayduck)
*ἔκλυσιν τοῦ σώματος | dissolution of the body. The idea is not articulated in Aristotle in quite the way Michael thinks it is, but it's a common belief that too much sex will weaken and destroy the body.
**ἔστι δ' ὅτε καὶ τῶν ἑπτὰ καὶ δέκα. This is rather specific.