Aristotle was born in Stagira, Chalcidice, in 384 BCE to Phaestis of Chalcis and Nicomachus, a physician at the court of King Amyntas II of Macedonia. While it is likely that Nicomachus died when Aristotle was young and Proxenus, a citizen of Atarneus, raised him. Aristotle’s medical legacy may have spurred his enthusiasm for biology. His focus on systematic research, dissection, and the sheer size of the biological writings in the corpus are indications of early medical training. At the age of 17, Aristotle entered Plato’s Academy and remained a scholar there until the death of Plato around 347 BCE. In his later ethical writings, Aristotle delineates the highest type of friendship from that of pleasure and utility. Plato’s Academy was a community of just this kind of friendship: one grounded in a life of contemplation and virtue, a life that can only be sought in the development of the intellect and the pursuit of the good in political life. Legend has it that Plato remarked that his school consisted of two parts: the body of students and “The Mind” of Aristotle, the first of Aristotle’s nicknames (Edel 1982). Plato also called him “The Foal” meaning that Aristotle kicked his teachers the way a foal kicks its dam (Natali 2013). His peers named him “The Reader,” a jibe referring to the servant who read aloud to the students, the common way of engaging texts in ancient times (Edel 1982). Aristotle did his own reading and would famously read so late into the evening that he held a rock over a tin pan to wake him if he dozed off (Edel 1982; Natali 2013).
At the Academy, Aristotle’s education included dialectical discussions and scientific activity including research into astronomy and the natural sciences. We can imagine, and have some evidence for, members of the Academy rigorously debating Plato’s theory of the forms: the ontological notion that reality is distinguished by what is material (ephemeral, corporeal, particular objects) and what is formal (eternal, incorporeal, universal objects). Material objects are perceived with the senses but strict knowledge of them is not possible. For Plato, scientific understanding (strict knowledge) amounts to logical demonstration, that is, deduction from what is necessary. Knowledge consists of a set of universal, necessary, eternal, and true propositions. As such, knowledge corresponds to that segment of reality that is eternal and universal. These “ideas” (ideas-another term Plato uses for the forms-eidos) are the objects of knowledge and, because knowledge is of what is real for Plato, constitute reality. Material objects constitute a secondary level of reality at best or are mere illusion at worst. This ontological and epistemological theory must have been at odds with the empirical predilections of a member of the cult of Asclepius because Aristotle famously argues that understanding begins with sensual perception in his Posterior Analytics. The basis of human knowledge is the ability to retain and revive these assorted sensory percepts, what he calls memory, and from experience humans notice symmetry (regularity) and asymmetry between and among properties. Experience is the basis of intuition, which is the first step in logical demonstration, the form that scientific propositions take according to Aristotle. In other words, it is through the experience of what humans perceive, i.e., particular objects, that they can ultimately gain understanding of what is eternal, universal, and necessary, i.e., the form. Aristotle’s theory of knowledge is grounded in his theory of reality wherein the form’s existence is dependent upon and concomitant to the matter’s existence. The empirical basis for his epistemology and his argument, contra Plato, that form is embedded in matter are why he is commonly referred to as a naturalist and considered to have developed a new school of thought.
Plato’s nephew, Spseusippus, succeeded him as head of the Academy. Some scholars intimate professional jealousy and Aristotle’s biological emphasis in philosophy, as opposed to that of Speussipus who leaned toward the mathematical, as the reasons for his departure from Athens. However, some regard his departure not as secession but an attempt to spread the political philosophy of the Academy. Aristotle and Xenocrates were invited by Hermias, then ruler of Assos, possibly to serve as political advisors but there is also evidence that there was a branch of the Academy there welcomed by Hermias. What appears clear is that anti-Macedonian sentiment fueled by the great Athenian orator Demosthenes influenced Aristotle’s emigration. At Assos, Aristotle met and married a young woman named Pythia, who was Hermias’ niece or perhaps his daughter, and they had two children, Pythia and Nicomachus. Aristotle’s famous work on ethics, the Nicomachean Ethics, was named after their son and they also raised Proxenus’ son, Nicanor, who became a general under Alexander. Much of Aristotle’s research on the life of animals appears to have been done between 347–335 BCE at Assos, Atarneus, Lesbos, and Macedonia because the particular species he observes are indigenous to these regions and he consistently mentions places especially in and around Mitylene, Lesbos, in the biological writings (Natali 2013). Aristotle took his bride to Lesbos in 345 BCE. There he met his closest collaborator and eventual heir to his school, Tyrtamos of Eresos, whom Aristotle would rename Theophrastus, which means “divine speech.” While Aristotle would establish in his Historia animalium (Inquiry into Animals) the founding document of biology, Theophrastus would do the same for botany in his Historia planatarum (Inquiry into Plants) (Fortenbaugh and Sharples 1988).
…the man whom it is not lawful for bad men even to praise,
Who alone or first of mortals clearly revealed,
By his own life and by the methods of his words,
That a man becomes good and happy at the same time.
Now no one can ever attain to these things again. (Jaeger 1934, p.107)
In 343–342 BCE, Aristotle accepted the invitation of Philip of Macedon to tutor his son Alexander. While there is much conjecture about the content of Alexander’s education, some scholars suggest that Aristotle’s relationship to the future leader of the known world proved beneficial to his own scholarship. Aristotle returned to Athens in 335 BCE to establish his own school at a grove sacred to the god Apollo Lyceus. At the Lyceum, Aristotle would discuss with his students and write about a number of exotic species that scholars argue were actually observed in detail by his nephew, Callisthenes, who accompanied Alexander and wrote of his eastward conquests. Aristotle focused on the systematic collection of research material and established the first library at the Lyceum. He was also the first thinker to devise a system of logic. His greatest contribution to the field was the syllogism but he may also be credited with numerous metalogical theses such as the principle of excluded middle, and the laws of bivalence and non-contradiction. Aristotle “walked about” with his students in the morning discussing philosophy, earning them the name “Peripatetic.” He carried on his work at the Lyceum organizing and writing most of the corpus until the death of Alexander in 323 BCE. Athens revolted, anti-Macedonian sentiment rose yet again, and Aristotle was charged with impiety in part for the hymn he had written for Hermias praising him as a god (Natali 2013). Aristotle decided not to face trial and retreated to Chalcis. He explains in a letter to Antipater, Macedonian general, and executor of Aristotle’s will, that he would not let Athens sin twice against philosophy referring to the trial of Socrates. Antipater crushed the Athenian revolt and Demosthenes drank poison in order to avoid capture. Aristotle passed a year later from a stomach ailment. He had created the first major library, invented logic and biology, tutored the greatest ruler of the ancient world, and would influence the thought of several cultures for millennia to come.
Scientific Method and Observation
Aristotle is the first major thinker to dedicate a special branch of knowledge to the systematic study of animal life. Of all the sciences he considers, he writes the most about biology. His research on animals constitutes roughly 25% of the extant corpus. Inquiry into Animals, Parts of Animals, Generation of Animals, On the Psyche (De Anima), Movement of Animals, Progression of Animals, Parva naturalia (a number of short essays on natural functions), and the last book of the Meteorology, all contain discussions of animal life. Aristotle’s method begins with (a) an inquiry grasping the differences between and the attributes of various animals and proceeds with an (b) investigation into their causes. The method of investigating the reasons why certain animals have particular attributes (b) Aristotle spells out in some detail at the opening of his Parts of Animals. Why it is that the elephant has an elongated trunk or the dolphin snores is the result of natural processes that are not random for Aristotle. Animals develop in specific ways in order to perform the functions that constitute their particular ways of living. They are unities of matter and form and he considers the ability to sufficiently explain the natural processes that result in animals developing in the ways they do the primary role of the natural philosopher.
In his various works concerning animal life, Aristotle presents descriptions of the attributes of over 200 different species. The Inquiry into Animals especially centers on these varied attributes and provides the first systematic classification of animals. Modern biological taxonomy is credited to Carolus Linnaeus’ publication of the tenth edition of Systema naturae in 1758 with its tidy, hierarchical categorization of class, order, genus, and species (Leroi 2014). Many of Aristotle’s kinds (genê) and greatest kinds (megista gene) correspond to modern classes, orders, genus, and species, but his classification lacks the range and coherence of modern taxonomy (Lennox 2001). This is due to his aim: Aristotle seeks to discover the nature of living things. For him, this amounts to demonstrating how it is that the attributes of an animal serve its purpose as a living being. His ordering of animal life is, therefore, teleological. It takes into account the genesis of animals, the material that serves as the locus for their development, the form or structural organization of their developing matter, and the purpose or final end of their development. Aristotle’s Generation of Animals provides an explanation for the causal relation between form and matter in the early development of animals reflective of his patriarchal culture. He argues throughout that the female is the material cause of generation because she provides the passive matter out of which the embryo is formed. The male, on the other hand, is the efficient cause of generation because his semen provides both the form of the embryo and the catalyst for its development (Connel 2016; Cooper 1988; Mayhew 2004).
The obvious problems with this and some of this other theories may, in part, be attributed to the way in which he gathered information. His method of acquiring data, what he calls examination of “phainomena,” involves direct observation in some instances. However, there were many exotic species that Aristotle did not directly examine but were meticulously described to him (see Callisthenes’ contribution above), and he considers analysis of informed and sometimes uninformed opinions (doxa) of animal anatomy and behavior as grist for the mill (Leroi 2014). These opinions could be those of other great thinkers including mythmakers and natural philosophers, people living adjacent to specific fauna, hunters, fishermen, etc. They sometimes led Aristotle to err; for instance, he infamously contends that the bison can defend itself from assailants by repeatedly projecting its excrement over long distances, excrement so pungent that it can burn the fur off hunting dogs and is only of this nature when the animal is alarmed (630a19–630b18). He also believes that spontaneous generation occurs in some animals, such as testaceans, anemones, grey mullets, and eels because he finds no evidence of their reproduction. But some fishermen’s tales also led him to keen observations; Aristotle collectively names dogfish, rays, torpedo fish, and sharks selakhe, noting their cartilage where most fish have bone, but he specifically notes the unique reproductive structures of the smooth dogfish, Mustelus mustelus. Smooth dogfish are born live and are connected to their mother’s uterus by an umbilical cord and placenta, features thought exclusive to mammals. Pierre Belon and Guillaume Rondelet confirm Aristotle’s findings in the sixteenth century and Johannes Muller discovered it again in 1839 in his Uber den glatten Hai des Aristoteles (On Aristotle’s Smooth Shark) (Leroi 2014). Further, Aristotle comments that a tentacle of certain male octopi (Argonauta argo) is involved in coitus. This tentacle was thought to be a parasite, because it commonly broke off and was discovered inside the female, until the mid-nineteenth century when it was confirmed a penis-tentacle.
Failing to recognize this extravagant paternal behavior in other European catfish, Louis Agassiz doubted Aristotle’s account until he received some Macedonian fish from the physician to the Greek king confirming Aristotle’s detailed observations. His assistant Samuel Garman named this novel species Silurus aristotelis in 1890, noting the four barbels on its chin in contrast to the six barbels of Silurus glanis(Leroi 2014).
Of river-fish, the male of the catfish is remarkably attentive to the young. The female after parturition goes away; the male stays and keeps on guard where the spawn is most abundant, contenting himself with keeping off all other little fishes that might steal the spawn, and this he does for 40 or 50 days, until the young are sufficiently grown to make away from the other fishes for themselves. The fishermen can tell where he is on guard; for, in warding off the little fishes, he makes a rush in the water and gives utterance to a kind of muttering noise. He is so earnest in the performance of his parental duties that the fishermen at times, it the eggs be attached to the roots of water-plants deep in the water, drag them into as shallow a place as possible; the male fish will still keep by the eggs, and, if it is young, will be caught by the hook when snapping at the little fish that come by; it, however, he be sensible by experience of the danger of the hook, he will still keep by his charge, and with his extremely strong teeth will bite the hook in pieces. (621a20-b1)
Animal Intellect and Teleology
Aristotle characterizes deer as possessing preeminent practical intelligence (phronêsis) in comparison to other quadrupeds. This is because of their effectiveness at avoiding threats in their environment. For example, stags when fattening up in the fall shun their usual haunts in order to evade detection by predators. They also hide when shedding their antlers so that their vulnerability is inconspicuous. A doe will give birth at roadsides in the hope that human traffic will scare off predators. She will then swallow the afterbirth and lead the faun to a lair of precipitous rock with only one entrance in order to better protect her offspring. Aristotle thinks other animals display intelligence in safeguarding too. He cites cranes setting lookouts for protection while sleeping. He believes deer, dogs, goats, panthers, and tortoises use medications to counteract poisons and alleviate pain (Foster 1997). He contends that all animals perceive weather changes and, according to their natures, either migrate before the frost bites or make other provisions. Finally, he notes birds and insects exhibiting technical proficiency (technê) in constructing nests and other protective environs.
All of this amounts to the possibility that animals possess intellect (vous) or reason (logos), a possibility that, oddly enough, Aristotle denies. What Aristotle does grant animals is sense perception and the cognitive ability to mentally represent percepts (a process he refers to as phantasia). Humans can willingly recollect these percepts and, in the process, stimulate the desire to pursue or avoid the objects represented. They can further signify these percepts linguistically and consider whether their pursuit or avoidance is conducive to their long-term good. These capacities (intentional memory, language formation, and consideration of future welfare) Aristotle considers unique to humans. However, he also believes nature proceeds according to a rational design because it is teleological. Thus plants and animals may not possess reason but their behavior can be exhibitive of reason. Plants seek out nutrition and grow but do not do so consciously. Animals seek nourishment and do so with the aid of sensation and appetite. They perceive what is painful as harmful and what is pleasurable as beneficial aiding in their ability to survive. They can recall past sense impressions in order to aid in this process, but they cannot do so willingly. Consideration of future welfare appears difficult, if not impossible, according to this schema. But Aristotle’s extraordinary examples of animals’ capacities to protect and ward off future harms are for him exhibitive of the rationality of the cosmos rather than that of individual beings.
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