Whether every flyer also walks.
Further, one asks whether every flyer also walks.
1. It seems not. When something is divided in terms of essential differences, what is contained under the one is not contained under the other. The ass is not contained under "rational [animal]" and neither then is man contained under "irrational [animal]," but "animal" is divided into "flyer" and "walker." Therefore, whatever is a flyer is not a walker.
2. Again, not every walker is a flyer. Therefore, not every flyer is a walker.
The Philosopher says the opposite.
One must reply that every flyer is a walker. And the reason for this can be that a flyer lives on things that exist on the ground. And this is why if it flew continuously or if it were stuck to the ground [by lacking feet] and could not make any forward progress, then it would not be able to pursue the food suitable to it. And this is why it has feet, so that it can get from place to place by flying, but by walking hither and thither it can seek its food. And, besides this, a flyer cannot raise its body from the ground suddenly. That is why birds first support themselves on their feet before they take flight, and some cannot fly without running beforehand, much as cranes first run a few steps and then fly.
Again, another cause may stem from their composition, because all animals are composed of heavy and light elements. But in walkers the light elements are material, and the heavy ones in their composition are rather like formal elements, and this is why they have their place on the ground. But in flyers the light ones are the formal elements, and the heavy ones are material, and so by virtue of the light ones they possess flight, and by virtue of the heavy they possess the ability to walk.
Moreover, one must understand that animals that have swift wings also have weak feet. And the reason for this can be that wings are made from subtle and light matter. And in the same way feet have a certain lightness in comparison to other parts of the body. For otherwise, if they had great weight, then the animal would neither be able to walk nor lift its feet without difficulty since the entire body would be heavy. And this is why the subtle material, which ought to be pushed out to the feet, is transmitted to the wings.
Or another reason can be predicated of the end, since such birds live off small flies and small animals and do not live much off earth-born things. And for this reason nature provides them with speed in their wings but weakness in their feet.
1. On to the arguments. To the first, one must reply that flyer and walker are not opposite differentiae unless they are understood as exclusive, and this is why they are compatible with one another.
2. To the second, one must reply that among walkers exclusively only the light elements exist in the way of matter, and this is why they only walk, but in flyers the light elements exist in the way of form, and the heavy elements exist in the way of matter, and this is why they can do both: both walk and fly.
Whether every animal emits a call [vox] .
One asks whether every animal emits a call.
1. It seems so. Because a call is an animal sound and occurs through the instrument of taste. For the tongue "is suited to two works of nature," as has been said in the second book of On the Soul, namely, "for taste and speech." Therefore, just as every animal has [a sense of] taste, so, it seems, it will have a call.
2. Again, calls are given to animals in order to express mutual affections. But this is useful for every animal, so that one may express its notion [conceptum] to another, namely, grief or joy, etc. But nature is not deficient in necessaries, and therefore, etc.
The opposite is obvious to the senses.
One must reply that not every animal emits a call. And the reason for this is that a call is caused by air that has been breathed in striking against the vocal artery. But not every animal breathes, and not every animal has a vocal artery. And this is why not every animal produces a call. And so bloodless animals, of which there are four genuses [ genera] according to the
Philosopher in the first book, do not produce a call. One genus is the cephalopods [ malakiae], which have a soft external flesh and hard internal flesh, like the octopi and the cuttlefish. And another genus, to the contrary, has a soft outer shell and soft flesh on the inside, like the crabs. A third genus has a hard shell, like the shellfish [ ostrea]. A fourth genus contains animals with sectioned bodies, like the bees, wasps, and flies. And similarly some animals with blood do not emit a call, like fish, because they do not breathe air and, as has been said, a call is caused by a movement of air.
One must further understand what is necessary to produce a good or delightful call: that the organs would be well aerated and, consequently, that they be of a warm and moist nature and not a dry and earthy nature. And because the human has a warm and moist nature, he has a charming call, and those whose organs are more moist although, nevertheless, temperately so, sing more sweetly, and therefore humans living in moist regions speak more sweetly than humans living in dry regions. And therefore, because the nightingale has an organ that is warm and moist and itself is the most temperate among the birds it sings better and more sweetly. But an ass does not sound well but rather brays rudely, on account of the earthiness of its organ and because it has a melancholy complexion. Neither do rapacious animals like the sparrow hawk [ nisus] sound well on account of the dryness of the tongue, which is proved by the fact that their tongue is black.
1. On to the arguments. To the first, one must reply that not every animal sound is a call [vox] but only the sound caused in the vocal artery. Further, not all animals have such an organ, not every animal has a tongue, and it is not necessary that every one that has the sense of taste have speech [ loquelam] because, as is said in the second book of On the Soul, "taste is for the sake of being" and "speech is for the sake of well-being." Thus it is absent from imperfect animals, for example, the shellfish [conchilia], or at least it is not apparent to us, and yet nevertheless they have the sense of taste.
2. To the second, one must reply that many animals are imperfect in comparison to the human and the cow, and this is why they do not require many things that are necessary to the perfect animals. Thus, a call would not be very useful for the crab because it would not seek out the things necessary to itself any better by having one, etc.
-  A., DA 22.214.171.124-47 (SZ 1: 62). On vox and animal language, see Irven M. Resnick and Kenneth F. Kitchell, Jr. (1996): 1-21.
-  The editor of QDA chose the reading lupi, "wolves," over pulpi, but this was ill advised, as pulpus is a variant for "octopus" (see Fr. poulpe and It. Polpo). In DA A. does discuss several "water wolves" but all are ferocious creatures like sharks and pike and even, incongruously, a seal. See DA 126.96.36.199; 188.8.131.52; 184.108.40.206;
-  The timbre of the mere vox is pleasing in and of itself, without any consideration of sermo, ordered speech. We, of course, are more prone to call our "call" a voice, but A. uses the same word for both.