In the Dictionary of the History of Ideas entry on “Theriophily” by George Boas (1973–1974), the citations range from Anaxagoras to Diogenes, from Democritus to Xenophon, from Philemon to Menander and Aristophanes, not to mention Theophrastus. But it is the notion of love or admiration for the animal world that is too sweeping.
Among Stoics, Academicians, and Epicureans, a debate had arisen about the possibility of an animal logos, for which the Stoic fragments offer plenty of evidence, though it is often contradictory (for a synthesis, see Pohlenz 1948–1955: I and II). The Stoics distinguish between a logos endiathetos, internally configured, that is, and a logos prophorikos, capable of manifesting itself externally. Now, whereas for Epicurus the difference between an animal voice (vox) and a human voice was simply one of degree, for the Stoics names are imposed by an explicit decision on the part of a rational mind, and therefore the various abilities attributable to animals are merely the consequence of an innate instinct of self-preservation. Along the same lines, Seneca (Ad Lucilium epistulae morales, III, cxxi) will remind us that animals are conscious of their own makeup, which explains their various abilities, and they have innate knowledge, but they are not endowed with reason.3 The adherents of the New Academy on the other hand professed more indulgent opinions with regard to the intellectual capacities of animals.
But it is precisely in the context of the Stoic debate that an argument comes to the fore, unanimously attributed to Chrysippus, and destined for great popularity. We will cite two versions of it.4 The one that is more famous today and more frequently quoted is that in Sextus Empiricus’s Outlines of Pyrrhonism (I, 69):
And according to Chrysippus, who shows special interest in irrational animals, the dog even shares in the far-famed “Dialectic.” This person, at any rate, declares that the dog makes use of the fifth complex indemonstrable syllogism when, on arriving at a spot where three ways meet, after smelling at the two roads by which the quarry did not pass, he rushes off at once by the third without stopping to smell. For, says the old writer, the dog implicitly reasons thus: “The creature went either by this road, or by that, or by the other: but it did not go by this road or by that: therefore it went by the other.”5
Sextus assumes, with respect to Chrysippus’s argument, a position closer to that of the Academicians (as will Porphyry in his De Abstinentia [On Abstinence from Killing Animals], in open polemic with the Stoics). Sextus reminds us in fact (again in his Outlines of Pyrrhonism, I, 65–77) that, through its behavior, the dog displays further aptitude for reflection and comprehension: it is able to choose between foods that are good for it and foods that are harmful; it is able to procure its food by hunting; it recognizes people’s merits by wagging its tail when it sees those with whom it is familiar and darting at strangers (it can therefore distinguish between right and wrong); it often shows prudence; and, finally, since it is capable of understanding its own passions and of mitigating them, it is able to remove its own splinters and clean its wounds, it knows it must keep the wounded limb immobile, and it can identify the herbs that will alleviate its pain. Thus, it shows that it possesses a logos. It is true that we do not understand the words of the animals, but then, we don’t understand the words of the barbarians either, who can assuredly speak; and therefore it is not absurd to believe that animals speak. And dogs certainly make different sounds in different circumstances.
But the information provided by Sextus does not appear till the second and third century A.D., while the discussion goes back somewhat earlier. It appears, for example, in the first century A.D. in the dialogue De animalibus (On Animals) of Philo of Alexandria. Philo’s brother Alexander speaks in favor of animal intelligence, citing in fact the classical example:
A hound was in pursuit of a beast. When it came to a deep [ditch] which had two trails beside it—one to the right and the other to the left, and having but a short distance yet to go, it deliberated which way would be worth taking. Going to the right and finding no trace, it returned and took the other. Since there was no clearly perceptible mark there either, with no further scenting it jumped into the [ditch] to track down hastily. This was not achieved by chance but rather by deliberation of the mind. The logicians call this thoughtful reckoning “the fifth complex indemonstrable syllogism”: for the beast might have escaped either to the right or to the left or else may have leaped. (De animalibus 45)6
In point of fact, for Chrysippus all the argument proved was that the instinctive behavior of animals prefigured a logical behavior, and in the dialogue Philo follows the Stoic line, polemically responding to Alexander:
Even the assertion of those who think that hounds track by making use of the fifth mode of syllogism is to be dismissed. The same could be said of those who gather clams or any other thing which moves. That they seem to follow a definite pattern is only logical speculation on the part of those who have no sense of philosophy, not even in dreams. Then one has to say that all who are in search of something are making use of the fifth mode of syllogism! These and other similar assertions are delusive fantasies of those more accustomed to the plausibility and sophistry of matters than to the discipline of examining the truth.
We agree that there are some decent and good qualities which are applicable to animals and many other functions which help preserve and maintain their courage; these are observed by sight. There is certainty in everything perceived or discerned in all the various species. But surely animals have no share of reasoning ability, for reasoning ability extends itself to a multiplicity of abstract concepts in the mind’s perception of God, the universe, laws, provincial practices, the state, state affairs, and numerous other things, none of which animals understand. (De animalibus, 84–85)7