During the final decades of the sixteenth century, Giordano Bruno tossed an intellectual grenade into European thought. The renegade Dominican friar was already dismantling traditional cosmology with his boundless universe and infinite worlds, but in his satirical Italian dialogue, the Cabala del cavallo pegaseo, he took aim at something far more intimate. He challenged human exceptionalism itself, constructing a daring thought experiment about the physical machinery of the mind.
Bruno introduced readers to Onorio, a wanderer who retained vivid memories of his past lives. Before walking the earth as a scholar, Onorio had laboured as an overburdened donkey carrying vegetables through the gates of Thebes. He had grazed on dangerous cliffs, fallen to his death over a thistle, and slipped past the waters of forgetfulness in the underworld. Because his memory survived intact, Onorio brought back an unsettling truth from the other side of existence. Across all creation, from philosophers and donkeys to oysters and stones, one single spiritual substance flows through changing physical envelopes.
To prove his point to a nervous companion named Sebasto, Onorio proposed a striking physical transformation. Consider a serpent whose head reshapes into the visage of a man. Give that serpent broad shoulders, articulate vocal cords, walking legs, and dexterous hands with nimble fingers. Bruno argued that this creature would immediately walk upright, debate philosophy, build architecture, and govern communities just like any human.
The reverse held equally true. Strip a person of their limbs, compress their bones into a single sinuous spine, and force their spirit into the body of a reptile. That person would cease to write treatises or found cities. They would hiss instead of speaking, burrow into the damp earth instead of constructing palaces, and perceive the world through the immediate needs of a creature in the grass.
Human supremacy, in Bruno’s estimation, rests upon physical tools rather than an exclusive divine spark. The hand is the premier instrument of intellect. It creates libraries, tools, and social institutions. Without hands, human brilliance remains imprisoned and unable to execute its potential. Many non-human animals might possess sharper awareness, refined senses, and profound natural wisdom, yet their bodies limit their outward craft. Moses described the serpent as the wisest of beasts, while ants and bees organise societies with astonishing precision. Humans merely possess the physical limbs required to conquer and transform their environment.
As someone tracking the long historical arc of ethical vegetarianism, I find Bruno’s insight breathtakingly modern. For centuries, mainstream Western philosophy justified the slaughter and exploitation of animals by drawing a sharp metaphysical wall between rational humans and soulless beasts. Classical thinkers in the Pythagorean lineage had long rejected this divide, teaching that the soul migrates across the entire living spectrum. Bruno pushed this ancient insight into radical territory by rooting intelligence within bodily organisation.
When you accept that the vital spirit animating an ox or a fish is identical in essence to the spirit inside a prince or a priest, the moral ground shifts beneath your feet. The traditional excuse for culinary cruelty dissolves. Exploiting a creature simply because it lacks hands to defend itself or vocal cords to plead in Italian suddenly feels arbitrary and unjust. The donkey is kin to the scholar, bound by the same universal life.
Bruno understood the profound danger of these ideas in an era dominated by strict religious orthodoxies. In the dialogue, Sebasto begs Onorio to stop his demonstrations, confessing that the argument sounds alarmingly convincing and threatens the faith passed down by his ancestors. Sebasto asks Onorio to treat the conversation as a mere fable. Onorio smiles and agrees, remarking that if his friend will not listen for the sake of serious doctrine, he should listen simply for entertainment.
This playful dissimulation was Bruno’s chosen shield. He cloaked revolutionary philosophy in comedic farce, dramatic banter, and satirical poetry. In the concluding section of the work, an actual donkey steps forward to debate a rigid academic, boldly demanding entry into a Pythagorean school. The beast challenges the philosopher to explain whether it is stranger for a human to act like an ass or for an ass to achieve human wisdom.
Behind the laughter lies a vision of ecological and moral kinship that still speaks to us today. Bruno shattered the illusion that humans stand outside nature as undisputed rulers of creation. He showed us that every living body is a temporary vessel navigating an infinite cosmos, and that wisdom wears many different forms depending on whether it breathes through lungs, glides on scales, or works with hands.
Bibliographic Information
- Title: The Animal Soul and the Human Mind: Renaissance Debates
- Subtitle: Ricerche filosofiche e materiali storico-testuali
- Series: Bruniana & Campanelliana, Supplementi, xxxvi · Studi, 15
- Editor: Cecilia Muratori
- Publisher: Fabrizio Serra editore
- Publication Places: Pisa · Roma
- Publication Year: 2013 (MMXIII)
- Edition: First Edition (Monographic Essay Collection with Original Latin/Italian Source Appendices)
- ISBN: 978-88-6227-582-8
- e-ISBN: 978-88-6227-583-5
- ISSN: 1127-6045
- Institutional Support / Funding: Ludwig-Maximilians-Universität München (LMU Munich Institutional Strategy LMUexcellent – Research Fellowships & LMU Mentoring-Programm; Center for Advanced Studies / CAS LMU)
- Historical Period Covered: 15th to early 17th Century (Renaissance and Early Modern Period: c. 1400–1640), with deep contextual anchors in Classical Antiquity (Presocratics, Plato, Aristotle, Epicurus, Lucretius, Plutarch, Porphyry, Sextus Empiricus, Galen), Late Antiquity/Early Church Fathers (Lactantius, Augustine, Philo of Alexandria), Medieval Philosophy (Johannes Scotus Eriugena, Avicenna, Averroes, Albert the Great, Thomas Aquinas, Meister Eckhart, Biagio Pelacani da Parma), and Early Modern transitions (Descartes, Spinoza, Bacon, Gassendi, Willis).
- Main Subject Areas: Renaissance Philosophy, History of Philosophy of Mind, Philosophical Anthropology, Zoology and Astrobiology, Cognitive Faculties in Nonhuman Animals, Intellectual vs. Sensitive Soul, Theories of Spontaneous Generation (generatio aequivoca / ex putri), Comparative Epistemology, Renaissance Skepticism, Animal Language and Semiotics, Affective Psychology and Passions.
(Ch. 9; pp. 170, 187)