Pythagoras and Vegetarianism

Pythagoras: The First Vegetarian of the Ancient World and a Contemporary of the Buddha?

Written by Jennafer Duerden, 3rd February 2026

Most people will be aware of Pythagoras’ theorem, a fundamental equation in Euclidean geometry that describes the relationship between the three sides of a right-angled triangle. Its teaching in countless classrooms throughout the world over the past centuries has ensured that Pythagoras’ name has lived on long after his death more than 2,500 years ago. It may, however, come as something of a surprise to learn that alongside his mathematical legacy, Pythagoras was also one of the earliest recorded proponents of a vegetarian diet in the Western world, leaving behind a philosophical school of thought that later influenced many scholars in the ancient Greek and Roman worlds.

Vegetarianism is experiencing what feels like a boom in the twenty-first century. Supermarket shelves are filled with plant-based alternatives, athletes extol the virtues of a vegan diet, and even fast-food chains now offer ‘meatless’ burgers. One would therefore be forgiven for assuming that vegetarianism is a relatively modern concept, particularly when considering what many of us associate with the ancient world: ritual animal sacrifice, images of spear-wielding hunter-gatherers, and the barbarism of the Roman games. Was Pythagoras a kind of vegetarian revolutionary, inspiring some of the philosophies adopted by so many today, or was he merely an anomaly in the society he inhabited, his musings on the subject largely lost during the centuries of medieval and pre-modern history following his death?

According to the Buddhist tradition, the Buddha lived from 563 to 483 BC, making him a contemporary of Pythagoras. There are notable similarities between Pythagorean and Buddhist philosophies concerning the consumption of meat, and it is possible that Greek schools of philosophy and their belief in metempsychosis were influenced by contact with Indian religions. Buddhism, however, differs greatly from Platonic thought in its understanding of the soul, and this essay also seeks to contrast Greek philosophy with Buddhist perspectives.

The difficulty in examining exactly what Pythagoras believed about vegetarianism lies in the fact that neither he nor his contemporaries left written records of his views. Fragmented accounts of Pythagoras only begin to appear around 150 years after his death, and his philosophy is further obscured by the mythological status he acquired by the third century AD, as well as by numerous forgeries of his alleged works that surfaced toward the end of the first century BC. To understand Pythagoras’ beliefs, we must therefore turn to later Greek mathematicians and philosophers who discussed his lifestyle and teachings and examine the philosophies of Socrates, Plato, and Aristotle, all born shortly after Pythagoras’ death.

A Brief Introduction to the Life of Pythagoras

Pythagoras, who lived from approximately 570 to 495 BC, was an Ionian Greek philosopher and noted polymath, skilled in many fields. Around the age of thirty, he travelled to Croton in southern Italy, where he established an ascetic school — in effect a commune —encompassing political, religious, and philosophical teaching.

Pythagoras’ legacy is deeply shrouded in myth. In antiquity, he was credited with discoveries ranging from musical tuning and harmonics to the theory of proportions, the sphericity of the Earth, and astronomical observations concerning Venus. Modern classical scholars, however, generally consider that many of these discoveries either predate his lifetime or should be attributed to colleagues and successors. He is more securely associated with philosophical ideas concerning the transmigration of the soul between bodies after death.

Mythological embellishment aside, Pythagoras exerted a profound influence on Plato and his teachings and was also admired by later scientific thinkers such as Kepler, Copernicus, and Newton. The portrayal of his ideas by Ovid, and later by the Roman Neoplatonist Porphyry, would go on to exert significant influence on the modern vegetarian movement.

Socrates, Plato, and Aristotle

A key source of evidence for the Pythagorean school of thought lies in the works of the fifth-and fourth-century BC Greek philosophers Socrates, Plato, and Aristotle. Born shortly after Pythagoras’ death, Socrates is widely regarded as the father of Western philosophy. His ideas profoundly influenced his pupil Plato, who in turn appears to have been heavily influenced by Pythagorean philosophy, making him a valuable source for understanding Pythagoras’ attitudes toward animals. In contrast, Plato’s own pupil Aristotle held markedly different views on animal intelligence, views that would go on to exert a powerful — and arguably negative — influence on Western attitudes toward animal welfare and meat consumption for centuries.

In the century following Pythagoras’ death, Greek intellectuals like Socrates, Plato, and Aristotle debated whether animals were capable of rational thought and, consequently, whether they should be regarded as equals to the human species and deserving of just treatment. Questions concerning animal reason and their purpose in the world were central to philosophical discourse.

The Downfall of Society

The views of Socrates are known to us only through Plato. In The Republic, Plato presents Socrates’ vision of a somewhat utopian, meat-free society:

‘The work-people will live, I suppose, on barley and wheat, baking cakes of the meal and kneading loaves of the flour… We shall also set before them a dessert, I imagine, of figs, peas and beans… And thus passing their days in tranquillity and sound health, they will, in all probability, live to a very advanced age and, dying, bequeath to their children a life in which their own will be reproduced.’

Socratean thought goes on to argue that such a society would inevitably begin to crave luxuries, and that it is precisely these luxuries — including meat — that would lead to its decline:

‘Further still, we shall want swine-herds likewise… and many other sorts of herds likewise, if any one is to eat the several animals… shall we not then, in this manner of life, be much more in need of physicians than formerly? Must we not then encroach upon the neighbouring country, if we want to have sufficient for plough and pasture? Shall we afterwards fight? Then we have found the origin of war.’

Here, the desire for luxury foods is directly linked to disease, territorial expansion, and ultimately war — themes that resonate strongly with later critiques of meat consumption.

Animals as Rational Creatures

Plato frequently emphasised the importance of reason over sensation and perception. His views on animal consciousness and sentience are complex and at times contradictory, but ultimately settle on a middle position. While he maintained that animals do not possess the same level of rationality as humans, he nevertheless considered them to be sentient beings.

Plato argued that animals lack the human capacity for analytical thought, stating that ‘the name “human being” (ἄνθρωπος) means this: the other animals do not reflect on or analyse that which they see’. Yet in Timaeus, he concedes that ‘everything that partakes of life may be truly called a living being’, extending this even to plants. Although such beings may lack rationality, they still possess sensation, pleasure, and pain, and therefore qualify as living entities.

Throughout his works, Plato frequently attributes animals with human-like moral or cognitive qualities, or alternatively describes humans as ‘beast-like’ in nature. In Laches, he speaks of a form of ‘thoughtless boldness’ shared by both humans and animals, while in Laws he praises animals that mate for life as ‘holy and just, remaining faithful to their first contracts of friendship’. Plato also repeatedly refers to the migration of souls between species, reinforcing the idea of a spiritual kinship between humans and animals — a theme closely aligned with Pythagorean thought.

Plato and Metempsychosis

Pythagoras believed in metempsychosis, or the transmigration of the soul, a belief also central to many Indian religions, including Hinduism. According to this doctrine, human souls may enter the bodies of animals after death. The consumption of animal flesh therefore becomes morally analogous to cannibalism.

As Porphyry explains:

‘If it should appear, according to Pythagoras, that they are allotted the same soul that we are, he may justly be considered impious who does not abstain from acting unjustly towards his kindred.’

Pythagoras’ principle therefore extends beyond mere diet: it is a moral injunction grounded in the recogninon of shared life and shared soul. By abstaining from the flesh of animals, one honours the connnuity of life and respects the possibility that the being before you might once have been, or might in the future become, a human. This ethical stance frames vegetarianism not as a maper of personal preference or health, but as an act of justice and spiritual responsibility. Later thinkers, including Porphyry and the Roman Neoplatonists, would emphasise this principle in their writings, linking it to broader arguments about virtue, the sanctity of life, and the cultivation of the soul. In this sense, the Pythagorean commitment to vegetarianism emerges as both a philosophical and a practical expression of their metaphysical worldview, illustranng how diet, ethics, and belief in the soul were inseparably intertwined.

Contrast with Buddhsim: Transmigration of Souls and Saṃsāra

According to Buddhist tradition, the Buddha lived from 563 to 483 BC, making him a contemporary of Pythagoras. While there are clear similarities between Pythagorean and Buddhist perspectives on meat consumption, Buddhism diverges sharply in its understanding of the soul. Rather than positing an unchanging soul that transmigrates between bodies, Buddhism teaches the doctrine of saṃsāra, in which there is no permanent self but rather a continuous cycle of rebirth driven by consciousness and karma.

This distinction is illustrated in the dialogue between the monk Nāgasena and King Milinda:

‘Suppose a man, O king, were to light a lamp from another lamp. Can it be said that the one transmigrates from, or to, the other?’

‘Certainly not.’

‘Just so, great king, is rebirth without transmigration.’

Despite this doctrinal diﬀerence, the parallels between Pythagorean thought and Eastern philosophies such as Buddhism remain striking. Both traditions challenge the assumption of human exceptionalism and question the moral permissibility of inflicting suﬀering on other living beings. In each case, ethical behaviour is closely tied to an understanding of life as interconnected and cyclical, rather than linear and anthropocentric. Whether articulated through the transmigration of souls or the cycle of rebirth, these philosophies encourage restraint, compassion, and an awareness of the consequences of one’s actions beyond the immediate human sphere. The conclusion that eanng meat is analogous to cannibalism is also echoed in Buddha’s words to Mañjuśri:

‘There is not a single being, wandering in the chain of lives in endless and beginningless saṃsāra, that has not been your mother or your sister. An individual, born as a dog, may afterward become your father. Each and every being is like an actor playing on the stage of life. One’s flesh and the flesh of others is the same flesh. Therefore the Enlightened Ones eat no meat.’

Aristotle and the Hierarchy of Life

Although a pupil of Plato, Aristotle’s views on animal rationality — and on humanity’s moral relationship with animals — are far less ambiguous. Regarded as the founder of biology, Aristotle wrote extensively on animals and on the nature of the soul. He proposed three types of soul: the nutritive soul (responsible for nourishment, growth, and reproduction), the sensitive soul (responsible for perception and movement), and the rational soul (mind).

In De Anima, Aristotle argued that plants possess only the nutritive soul, animals possess both the nutritive and sensitive souls, and humans alone possess all three. Animals are therefore excluded from rational thought. This view is reinforced in The History of Animals, where Aristotle asserts that while many animals have memory and are capable of learning, only humans can recall the past deliberately and engage in rational deliberation. In this way, Aristotle established a hierarchical model of life in which animals exist for the use of humans. By denying animals the capacity for rationality and true sentience, he provided a powerful philosophical justification for the consumption of meat — one in stark contrast to Pythagoras, that would profoundly shape Western thought for centuries to come.

The Influence on Modern Life

Aristotle exerted a significant influence on medieval Christian ethics and, through them, on many prevailing Western attitudes toward animals today. While Aristotle acknowledged that ‘in all animals there is something natural and beautiful’, one cannot help but wonder how attitudes toward vegetarianism might have developed had he adopted a more Platonic view of animal sentience.

This ancient Greek debate about animal rationality continues into the present day. Despite growing evidence of animal intelligence — from corvid funeral-like behaviours to the complex social reasoning of elephants, lions, and ravens — many still argue that animals lack higher-order cognition and are therefore subordinate to human interests. Modern vegetarianism often draws more heavily on environmental or health concerns than on animal welfare, which remains, for many, a fringe ethical position.

Factory farming, driven by an insatiable demand for meat, contributes to pollution, environmental degradation, and climate change, while also exacerbating health crises such as heart disease and obesity. Humanity’s persistent tendency to elevate itself above all other forms of life, combined with an endless appetite for luxury, has led to war, famine, genocide, and widespread suffering. In this sense, we may be living in precisely the period of decay and decline predicted by Socrates and Plato — a decline that might have been avoided had greater heed been paid to the Pythagorean vision.

Pythagoras’ Legacy

Pythagoras’ advocacy of vegetarianism, then, can be understood not merely as a dietary preference but as a moral position grounded in a broader metaphysical worldview. By rejecting the consumption of animals, Pythagoreans sought to minimise harm and maintain spiritual purity, reflecting a belief that violence against other living beings ultimately corrupts the human soul. Although later Western philosophy would largely abandon this outlook in favour of more hierarchical conceptions of life, the persistence of vegetarian ethics in Eastern traditions suggests that such ideas were neither marginal nor unsustainable.

In the modern world, where industrialised farming and environmental degradation have intensified humanity’s impact on other forms of life, these ancient perspectives take on renewed relevance. The philosophical questions raised by Pythagoras and his intellectual descendants — concerning the moral status of animals, the nature of the soul, and humanity’s place within the natural order — continue to resonate today. While it would be anachronistic to impose contemporary ethical frameworks onto the ancient world, revisiting Pythagorean vegetarianism invites reflection on whether Western philosophy may have overlooked a more compassionate and sustainable path.

Ultimately, Pythagoras’ legacy extends far beyond geometry. His influence on ethical thought, particularly in relation to humanity’s treatment of animals, reveals an alternative philosophical tradition that challenges long-standing assumptions about dominance, consumption, and moral responsibility. In this sense, the vegetarian ideals associated with Pythagoreanism are not relics of an obscure ancient sect, but part of a wider and enduring conversation about how humans ought to live.

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