Written by Shannon Johnson-Finn
1§1 The understanding of animals changed drastically throughout antiquity. Civilizations around the Mediterranean held different animals in prestige, which effected how they acquired medical knowledge. Shifts in the cultural understanding and importance of animals abstracted the relationships of the medical dissector, examiner, scientist and the animal. This shift in importance and understanding allowed for an apathy to develop towards the emotions of animals that was essential for the acquisition of medical knowledge and comparative medicine. Aristotle’s zoological taxonomy marks the shift towards the moral separation of humans and animals that allowed for the acquisition of medical knowledge for comparative medicine.
1§2 To understand how revolutionary Aristotle’s work was for comparative medicine, we must first understand the role of animals prior to his taxonomy. Notably in Egypt (c. 4000-300 BCE), animals maintained both an economic and religious importance. For example, the cat in Egypt was so important that when the family cat died, everyone in the household shaved their eyebrows as a sign of mourning. Further, the death penalty could be incurred by someone who killed a cat, even if it happened by accident. The Egyptians held cats in high respect for two main reasons. Firstly, cats served an economic role which involved them chasing away mice that destroyed grain supplies. Secondly, cats held the relgious function of being the enemies of the godly embodiment of chaos, Apep. Similar to cats, the ibis was also symbol of religious importance. However, the ibis clearly held less prestige than cats since they were bred for the purpose of embalming, and offered as sacrifice to the god Tehuti.
1§3 Naturally, this leads to the postulated origin of Egyptian anatomical knowledge, mummification. However, many scholars argue that the process of mummification offered little opportunity for the study of anatomy, and that too much significance has been placed on what medical knowledge the Egyptians may have acquired through embalming. It is accepted that besides sacrificial dissection, organ divination provided the earliest form of anatomical and pathological knowledge for the Egyptians. If during this time, in a particular society’s evolution, living animals ceased to be incarnations of their gods, this first method for productive advances in comparative medical disappeared. In short, once animals’ ties to the gods became less important the acquisition of medical knowledge though sacrificial dissection and organ divination was staunched. So if cultures in the Mediterranean weren’t effectively procuring medical knowledge from religious rites, what was going on?
1§4 From Homer onwards there is consistent evidence that animals are placed within a particular taxonomy separate from humans. In many texts, what separates men from animals is strongly emphasized. In particular, humans are marked as beings that both offer sacrifices to the gods and hunt in special ways. For ancient authors, humans show a capacity for thought and a connection to the gods that animals are incapable of.  A strong moral contrast is drawn between men and animals where man is defined as having justice, and animals simply eat one another. Contrasts between animals, men, divine creatures, and demi-gods, gods are evidence that animal taxonomy is incorporated in a much broader context. This taxonomy is then used in practice to justify the medical discoveries of Hippocrates.
1§5 The Hippocratic corpus is a joint contribution of a succession of many earlier and contemporary priest-healers, which had set the precedent for the acquisition of medical knowledge. For example, it is known that Diogenes of Apollonia, who was a contemporary of Hippocrates, described the blood vessels of animals (History of Animals, III 2, 511b30, 513a11). Hippocrates’, On Fractures (II 43, IX 1) and On the Heart (IX 82), contain anatomical knowledge that was most likely obtained from the dissections of animals. These works also show a distinct minimization of animals’ capacities for thoughts, feelings, and emotions that had curtailed animal dissections in previous cultures and time periods. The shift in the cultural significance of animals following Homer is likely to have contributed to the moral apathy necessary to perform the dissections necessary for Hippocrates’ work, and comparative medicine. It is with Aristotle’s taxonomy that the relationship between the animal and the dissector is altogether abstracted.
1§6 Aristotle’s work did not exist in a vacuum. Prior to Aristotle’s taxonomy was Plato’s taxonomy for animals. Plato, unlike Aristotle, is unable to yield a consistent dichotomous classification of animals. Plato’s nascent interest in separate animals was possibly due to the fact that he was more concerned with an entire cosmology of the universe rather than just forming a taxonomy for animals. Rather, Plato’s points are conflicting, and are altered to suit his needs at different points.  Plato is important because he formulated the antecedent of Aristotle’s zoological taxonomy. Aristotle, unlike Plato, is able to construct a stable taxonomy. As seen with Plato in particular, the desire to classify animals existed prior to Aristotle. Animals held religious and economic importance for millennia; however, Aristotle’s interest in their internal structures, functions, and classification was new. 
1§7 Animal taxonometric work truly came to fruition with Aristotle. Aristotle himself did not complete a definitive taxonomy, but rather established the core differences between primary groups within the taxonomy. However, it is with Aristotle that there is an extant body of literature relevant to the concern of a shifting importance and understanding of animals. This shift allowed for an apathy towards animals that was essential for the acquisition of medical knowledge and comparative medicine.
1§8 Aristotle expanded on the separation of animals from men and the gods that prior authors had established. Humans, for Aristotle, topped the taxonomy because of their superior mental capabilities, but were analogous to animals in body. Humans and animals did not occupy the same moral plane because Aristotle believed that humans alone possessed an intelligence and rational souls. Despite the fact that Aristotle, at certain points, discusses animals as intelligent (Arist. Metaphysics. 12.10., De an. 3.12., Parts of Animals. 4.14.), only man has the power of reasoning for himself. In contrast, animal souls possessed emotion alone and not the capability to reason. Naturally, Aristotle’s idea that animals were lesser beings than humans removed any moral obligations that might hold back a dissector.
1§9 As result, for Aristotle, there was no such thing as justice or injustice towards animals: justice requires reason. Aristotle’s Parts of Animals (PA, V 645a 28), notes that looking at the constituent parts of human beings causes considerable distaste, but one can learn a great deal from the study of plants and animals. In this statement Aristotle appears to advocate for comparative medicine. Furthermore, in two specific passages Aristotle says that one should not simply observe, but should do deliberate research in order to reveal the causes of things (PA, 645 a 7, a 21). Naturally these passages discuss animals with Aristotle saying that animal investigation should be approached without shame, “…we ought not to hesitate nor to be abashed, but boldly to enter upon our researches concerning animals of every sort… (PA, 645 a 21)”. Thus, Aristotle’s zoological taxonomy marks the shift towards the moral separation of humans and animals that allowed for the acquisition of medical knowledge for comparative medicine. Aristotle himself, never discussed ethical issues regarding the use of animal bodies either live or dead, but it can be argued that Herophilos and Erisistratos applied this logic in order to rationalize their dissections of humans.
1§10 It is unclear as to whether Aristotle’s work directly influenced Herophilos and Erisistratos’ human dissections. The anatomists of Alexandrian Egypt operated under a unique set of cultural circumstances. However, it is apparent that the significance of Aristotle’s dispassion towards the emotions of animals influenced the work of the Roman doctor, Galen.
1§11 Aristotle’s taxonomy for animals undoubtedly influenced Galen’s work. Nowhere is Aristotle’s influence on Galen clearer than in his work On Anatomical Procedures. In On Anatomical Procedures, Galen discusses how animal dissection and vivisection should be used exclusively for comparative medicine (On Anatomical Procedures 1.2. 223., 1.4). For Galen, the purpose of animal dissection is only to gain knowledge about the human body. Galen advised his students to cut without pity or compassion, and to ignore the cries of the animal because in the name of science these things were permissible.  When discussing the vivisection of animals Galen says, “It is surely more likely that a non-rational brute, being less sensitive than a human…will suffer nothing…” In this excerpt, Galen’s pattern of cognition is directly reliant of Aristotle’s taxonometric work on animals. Galen clearly views the animal he mentions as possessing a lesser mental capacity. Thus, Galen asserts that the “brute” will not suffer from such a wound. Galen’s methods would be considered cruel now, but his dispassion towards animals was essential to learning about human anatomy through comparative medicine. Galen established a legitimate way to obtain knowledge concerning anatomy, and also established an emotional dispassion based off of Aristotle’s taxonomy with which to bring to a dissection or vivisection.
1§12 Whether in ancient Egypt, Homer, Plato, Aristotle, or Galen the relationship between the medical dissector and the animal was important for determining the acquisition of both anatomical and comparative medical information. Aristotle’s work in particular created a shift towards the moral separation of humans and animals that allowed for the acquisition of medical knowledge for comparative medicine.
 Schwabe (1978), 10. As Schwabe notes in his book, specific cultures held certain animals in high regard due to their perceived economic and religious value.
 Schwabe hypothesizes (Schwabe, (1978), 29), that the beginning of Egyptian medicine predates historical texts. With the adoption of commensal then hunting occupations, it is hypothesized that primitive Egyptians acquired a practical knowledge of animal habits and anatomy. The Egyptians’ need to predict and ward off diseases possibly caused them to resort to divination, totemism, and animal sacrifice according to Schwabe.
 Ibid, 85.
 Orlin (2007), 135.
 cf. (Orlin (2007), 35).
 Harris (1971), 125.
 Majno (1975), 138. For more on the development of biomedical theory and comparative medicine in Egypt, see Gordon and Schwabe (2004).
 cf. (Schwabe, 1978, 85).
 Ibid, 120.
 Ibid, 110.
 Lloyd (1983), 10.
 There is a taxonomy that strictly divides humans from animals in Hesiod’s, Works and Days (276f).
 Ibid, 11.
 cf. (Schwabe, (1978), 10).
 Ibid, 11.
 Ibid, 119.
 Aristotle. The works of Aristotle: Historia Animalum. Edited by J. A. Smith and W. D. Ross. Translated by D’Arcy Wentworth Thompson. Oxford at the Clarendon Press, 1910. (HA).
 It is unclear which works in the Hippocratic corpus can be directly attributed to Hippocrates of Kos.
 cf. (Lloyd, (1983), 16-26). cf. (Guerrini, (2003), 10).
 cf. (Guerrini, (2003), 15).
 Ibid, 16.
 See Sophist (220ab), Politicus (264f), and Timaeus (91d).
 cf. (Guerrini, (2003), 10).
 Lloyd (1971), 104.
 cf. (Lloyd, (1983), 16).
 Ibid, 10.
 cf. HA 487a. The social behavior of animals is taken into account, and Aristotle discusses the differences in manner of life, in activities, and in disposition. Alternatively, the Parts of Animals (II 648a/650b) correlates differences in animal behavior and intellectual capabilities with differences in qualities of the animal’s blood. This section includes humans as an example. For Aristotle, animals are classified differently and therefore have inherently different, but consistent characteristics.
 cf. (Guerrini, (2003), 10).
 Ibid, 11.
 Tredennick, trans. (1977). Wentworth Thompson, trans. (1910).
 cf. (Lloyd, (1983), 26).
 cf. (Guerrini, (2003), 7).
 cf. (Majno (1975), 327).
 Singer, trans. (1956), 2-5, 9.
 cf. (Guerrini, 2003, 10-12).
 cf. (Singer, trans. (1956), 192).
Gordon, Andrew H, and Calvin W Schwabe. 2004. The Quick and the Dead : Biomedical Theory in Ancient Egypt. Egyptological Memoirs, 4. Leiden: Brill.
Guerrini, Anita. 2003. Experimenting with Humans and Animals : From Galen to Animal Rights. Johns Hopkins Introductory Studies in the History of Science. Baltimore, Md.: Johns Hopkins University Press.
Harris, J.R. 1971. The Legacy of Egypt. 2nd Edition. Oxford: Clarendon Press.
Lloyd, G. E. R. 1983. Science, Folklore, and Ideology: Studies in the Life Sciences in Ancient Greece. Cambridge: Cambridge University Press.
Lloyd, G. E. R. 1971. Early Greek Science: Thales to Aristotle. Ancient Culture and Society. New York: Norton.
Majno, Guido. 1975. The healing hand: man and wound in the ancient world: 8 Alexandria the Great. Harvard University Press.
Orlin, Louis L. 2007. Life and Thought in the Ancient Near East. Ann Arbor: University of Michigan Press.
Schwabe, Calvin W. 1978. Cattle, Priests, and Progress in Medicine. The Wesley W. Spink Lectures on Comparative Medicine, V. 4. Minneapolis: University of Minnesota Press.
Singer, Charles, trans. 1956. Galen. On anatomical procedures: De anatomicis administrationibus. London.
Tredennick, Hugh, trans. 1977. Aristotle: Metaphysics, Volume II Books 10-14. Oeconomica. Magna Moralia. Cambridge, MA: Harvard University press.
Wentworth Thompson, D’Arcy, trans. 1910. The works of Aristotle: Historia Animalum. Oxford.