In the extensive collection of moral essays known as the Moralia, the ancient Greek biographer and philosopher Plutarch produced some of antiquity’s most direct arguments against the slaughter and consumption of animals. Born around AD 46 in Boeotia, Plutarch studied rhetoric and philosophy in Athens and served as a priest of Apollo at Delphi. Although better known for his Parallel Lives of Greek and Roman statesmen, his moral treatises include three works addressing animal treatment and vegetarianism: Whether Land or Sea Animals are Cleverer, Beasts are Rational, and the two-part essay On the Eating of Flesh. These texts engage with classical philosophical traditions while systematically attacking contemporary practices of animal exploitation.
Advocating vegetarianism within the Graeco-Roman world placed an individual outside mainstream cultural life. Meat consumption, animal husbandry, religious sacrifice, and the public execution of animals formed core elements of civic existence. While philosophical figures such as Plato and Theophrastus, as well as the Pythagorean school, had praised meat-free diets, vegetarian adherence remained marginal. Animals played practical economic roles as beasts of burden and sources of wool or milk, making their slaughter an inefficient use of resources in everyday life. However, meat held deep symbolic weight. Animal sacrifice served as the foundation of public religion in Greece and Rome, functioning as a communal covenant between mortals and deities. Refusing to consume sacrificial meat meant rejecting civic religious participation, an act widely viewed as impiety and communal disloyalty.
In Roman imperial society, animal violence also defined public entertainment. Amphitheatres across the empire staged regular spectacles involving the slaughter of animals, including organized hunts, the execution of condemned criminals by wild beasts, and theatrical re-enactments. During the dedication of the Colosseum in AD 80, the Emperor Titus had nine thousand animals killed over one hundred days. Trajan later marked his Dacian triumph in AD 107 with games in which eleven thousand beasts were slaughtered over one hundred and twenty-three days. These spectacles served to display Roman authority, imperial dominion over the physical natural world, and the established hierarchy placing humans above animals and beneath the gods. In this environment, arguments against the mistreatment of animals countered deeply entrenched social and political norms.
Plutarch began his critique of human cruelty in Whether Land or Sea Animals are Cleverer. Structured as a dialogue between several speakers, the text opens with Autobulus, Plutarch’s father, reviewing an earlier discussion on hunting. Autobulus argues that the practice of hunting originally cultivated human violent impulses. Comparing this escalation to an Athenian execution that led to widespread state violence, he suggests that hunting wild predators under the guise of self-defence eventually normalized the slaughter of domestic animals like horses and dogs. The dialogue directly confronts the Stoic assertion that animals lack reason. Autobulus argues that animals display varying degrees of rationality, visible in parental devotion and adaptive hunting behaviours. While Soclarus defends human intellectual superiority, Autobulus highlights animal sensory capacities and denounces hunting as unnecessary cruelty. Although Plutarch does not reject all human use of animals, he argues for a standard of humane treatment modelled on mutual obligation, where domestic animals perform labour in exchange for care and sustenance.
In Beasts are Rational, commonly known as Gryllus, Plutarch presents an ethical critique through the framework of Homer’s Odyssey. Set on the island of Circe, the dialogue imagines a conversation between Odysseus and one of his former crewmen, who has been transformed into a pig named Gryllus. Given speech by the sorceress, Gryllus refuses Odysseus’s offer to return to human form, arguing that animals lead more virtuous lives than humans. Gryllus maintains that animal bravery is genuine and distributed equally across sexes, whereas human courage requires artificial enforcement through laws, education, and the fear of disgrace. Furthermore, he condemns human luxury, highlighting that animals seek only natural sustenance, avoid artificial perfumes, and do not pursue material wealth. Gryllus contrasts animal dietary restraint with human omnivorous habits, arguing that human culinary desires drive excessive indulgence, dietary corruption, and social decay.
Plutarch’s central vegetarian argument appears in On the Eating of Flesh, an impassioned, fragmentary work attributed to his youth. Rather than asking why Pythagoras avoided meat, Plutarch asks how the first human could have brought dead flesh to their lips, directly invoking the sensory revulsion of blood, viscera, and the sounds of slaughter. He catalogs the violent methods employed to cater to elite culinary tastes, such as thrusting red-hot spits down the throats of pigs, trampling the udders of pregnant sows, and containing animals in darkened enclosures to fatten them. Plutarch further argues from physiology, asserting that the human body lacks the natural weapons of predators, such as claws, sharp teeth, and beaks, and cannot easily digest raw meat without fire, tenderizing, and heavy seasoning.
Alongside ethical and physical considerations, On the Eating of Flesh employs traditional anthropocentric arguments. Plutarch asserts that meat consumption thickens and degrades the human soul, dulling spiritual perception. He also reiterates the moral warning that violence against animals desensitizes people and inevitably leads to violence against fellow humans. Finally, Plutarch invokes the Pythagorean doctrine of metempsychosis, the transmigration of souls, noting that killing an animal carries the risk of destroying an incarnate human soul.
While these three treatises do not form a strictly unified philosophical system and survive with abrupt, incomplete endings, they represent a significant body of ancient vegetarian literature. Plutarch challenged the prevailing Stoic view of animals as unreasoning resources, combining Pythagorean traditions with a sustained focus on animal distress. Within an imperial Roman society that prioritized civic sacrifice, natural subjugation, and arena slaughter, Plutarch’s writings provided an early philosophical framework asserting the moral consideration of nonhuman life.
Bibliographic Information
- Title: Eating and Believing: Interdisciplinary Perspectives on Vegetarianism and Theology
- Subtitle: Interdisciplinary Perspectives on Vegetarianism and Theology
- Editors: David Grumett and Rachel Muers
- Contributors: Michael Beer, David Brown, Samantha Jane Calvert, David Clough, Erika Cudworth, Daniel Dombrowski, James R. T. E. Gregory, David Grumett, David G. Horrell, Nathan MacDonald, Rachel Muers, Michael S. Northcott, Nigel Pleasants, Teresa M. Shaw, Christopher Southgate, John Wilkins
- Publisher: T&T Clark (A Continuum imprint), London and New York
- Publication Year: 2008
- Edition: First Edition (Hardback)
- ISBN-10: 0-567-03284-1
- ISBN-13: 978-0-567-03284-3
- Historical Period Covered: Ancient Near East / Biblical Antiquity (c. 1000 BCE–1st century CE), Classical and Hellenistic Greece (6th century BCE–2nd century CE), Early Christianity and Late Antiquity (1st–5th centuries CE), Early Medieval Ireland and Carolingian Europe (5th–9th centuries CE), High and Late Middle Ages (12th–15th centuries CE), Enlightenment and Early Modernity (16th–18th centuries), Victorian and Edwardian Eras (19th–early 20th centuries), and Contemporary Postmodernity/21st Century.
- Main Subject Areas: Practical and Systematic Theology, Biblical Studies (Old and New Testament Exegesis), Patristics and Late Ancient History, Classical Greek and Roman Philosophy, Celtic and Medieval Monastic History, Ecofeminist Theory, Philosophical Ethics (Deontology, Utilitarianism, Virtue Ethics, Social Contract Theory), Historical Sociology, and Environmental Ethics.
(Ch. 6, pp. 101–103)