Giordano Bruno’s books and papers described an endless, eternal universe governed by intrinsic laws that produced innumerable worlds. This model, both in its infinitude and its implicit displacement of Earth from the center of the cosmos, challenged the Catholic view of the world and ultimately led to Bruno’s execution by the Inquisition.

Giordano Bruno entered a Dominican monastery in Naples, Italy, in 1565. He was ordained priest in 1572 and earned a doctor of theology degree in 1575. Despite his Catholic background, however, Bruno developed a cosmological model antithetical to the teachings of the Church. He posited an unprecedented, systematic explanation of universal nature, which he published from 1583 to 1591. The Inquisition, Inquisition;Italy Roman Catholic church courts in Europe designed to root out heresy, at that time under Clement VIII, declared Bruno a heretic and had him imprisoned in 1592. He refused to recant his position in prison and was finally burned at the stake on February 19, 1600. Bruno, Giordano
Clement VIII
Clement VIII
Copernicus, Nicolaus
Bruno, Giordano

From 1232, the Roman Catholic Church had used Inquisition courts to prosecute those who questioned its teachings, whether in matters of religion or science Science;religion and . The Church believed that religion and science, as forms or bodies of knowledge, worked together to reveal God’s ways. In Bruno’s lifetime, the Church feared challenges to its authority from the Protestant Reformation, an effort to return to the original teachings of Jesus Christ. The Reformation Reformation;Italy stressed the individual in matters of faith and revolted against medieval religious attitudes. The Reformation both compounded and was fueled by Renaissance cultural trends that emphasized human ability, potential, and versatility. These trends hastened the growth of science, in which direct observation of physical nature became more important than biblical testimony and the claims of ancient and medieval writers and philosophers. Bruno’s radical open-mindedness, knowledge of several fields, generalized curiosity, and soaring imagination typified both Reformation and Renaissance culture.

Already in 1575, the Dominican Order, whose members often served as judges on the Inquisition courts, had begun to suspect Bruno of censurable offenses. The order’s priests believed he contested the Catholic Church’s interpretative control over the Bible and enforcement of orthodoxy upon believers, as well as the full sufficiency of traditional knowledge, biblical or secular, to answer life’s vast and final questions. In 1576, Bruno was excommunicated from the Catholic Church. The order charged him with doctrinal errors. Further, it charged him with denying the Church’s view of the universe as a perfect spherical shape in which the planets and other celestial bodies, including the Sun, revolved around the Earth, thought to be the center of all things, a privileged place created by God solely for human beings.

Bruno rejected the closed, immutable model of the universe developed by the Church fathers and medieval theologians who had drawn upon the Bible, the Greek philosopher Aristotle (384-322 b.c.e.), and the Greco-Egyptian astronomer Ptolemy (c. 100-c. 178). He favored the views of several early Greek philosophers who described an open-ended, dynamic universe, including Anaximander (c. 610-547 b.c.e.), Anaxagoras (c. 500-c. 428 b.c.e.), and Heraclitus of Ephesus (c. 540-c. 480 b.c.e.). In addition, he was influenced by Lucretius (c. 98-55 b.c.e.), a Roman philosopher, whose poem De rerum natura (c. 60 b.c.e.; On The Nature of Things, 1682) had described a universe made up of atoms that had evolved out of a chaos of all possible laws and would forever remain in a state of change or flux governed by those natural laws. Bruno had also been influenced by Nicholas of Cusa (1401-1464), a Roman Catholic cardinal. In his book, De docta ignorantia (1440; Of Learned Ignorance, 1954), he depicted an eternal, limitless universe which represented a manifestation of God and in which the stars were other worlds.

Bruno, moreover, had access to new knowledge that his predecessors had not had. It provided him with new points of departure for philosophic and scientific speculation. In particular, Bruno had learned from Nicolaus Copernicus (1473-1543), the Polish astronomer who, in his treatise, De revolutionibus orbium coelestium (1543; On the Revolutions of the Celestial Spheres, 1939; better known as De revolutionibus
De revolutionibus (Copernicus) ), had described the Sun as the center of all things, with Earth revolving around it.

For nearly sixteen years after his excommunication in 1575, having escaped from the Church’s control, Bruno lived as an itinerant philosopher, teacher, and writer. He traveled throughout Europe in search of the freedom of thought and expression as well as the economic security necessary to develop, synthesize, and publish his ideas. He remained, however, a marked man, singled out as an object of suspicion.

In 1583, having arrived in England, Bruno started to write important cosmological works, including La cena de le cereni (1584; The Ash Wednesday Supper
Ash Wednesday Supper, The (Bruno) , 1975), De la causa, principio et uno
De la causa, principio et uno (Bruno) (1584; on cause, prime origin, and the one), De l’ infinito et mondi (1584; On the Infinite Universe and Worlds
On the Infinite Universe and Worlds (Bruno) , 1950). After returning to the continent, prior to his arrest by the Inquisition, he published De monade, numero et figura liber consequens quinque de minimo magno et mensura
De monade, numero et figura liber consequens quinque de minimo magno et mensura (Bruno) (1591; on the monad, number, and form in one book: being a sequel to the five books on the great minimum and on measurement) and De innumerabilibus immenso et infigurabili: sue de universo et mundis libri octo
De innumerabilibus immenso et infigurabili (Bruno) (1591; on the innumerable, the immense, the formless: on the universe and worlds in eight books).

In these works, Bruno formulated a theory of everything, which linked physical nature on the smallest scale, the minima, with physical nature on the largest scale, the maxima. He described a boundless, eternal, all-pervading, interacting unity of space, time, matter, and energy or inherent momentum within matter. God united diverse natural phenomena. Settling Copernicus’s work into what he regarded as the correct framework, Bruno argued that there was no margin, limit, center, surface, or absolute up or down in the universe; it extended infinitely in all directions. The universe contained numberless stars or suns around which revolve worlds or planets, likely inhabited by other intelligent beings shaped by physical conditions of their worlds. The universe contained finite bodies whose motion or rest could only be determined by comparing one body with another, and it would appear generally the same to an observer on any heavenly body.

Bruno thought the universe itself was immovable, but everything in it, its matter and energy, was in a state of continual motion and change that was irregular in rate and scale depending on local variables. Nevertheless, he believed that despite this incessant motion and change, physical nature—particles, bodies of matter, and energy—followed laws or rules that made change or complexity possible. Universally valid constants, the result of God’s universal intellect, underlay seen and unseen regularities of nature. Moreover, Bruno believed that after matter and energy formed bodies with particular shapes, living and non-living, there occurred a process of redistribution of matter and energy through decay or destruction which resulted in new or continuous creation or evolution. He apparently thought that after long periods of time the values of the universal constants changed and thus the outcomes changed, producing new patterns, systems, and differences without end.

Bruno’s cosmology—pioneering, comprehensive, and strikingly modern—might well place him among the founders of modern cosmology. In his time, however, it was the ultimate reason for his condemnation. He thought that a far greater diversity of life, of living forms and behavior of those forms, existed than any one expression of religion, including the Roman Catholic, or any one branch of science or knowledge could account for, explain, or describe. His cosmology, as well as his own life and death, indicated that all uniformity of thought, all censorship, must be rejected, that more and more wonderful questions and mysteries awaited discovery. The sheer scope of the universe was such that it must always remain imperfectly known, endlessly open.

Bruno influenced a number of important philosophers, scientists, and writers, including Baruch Spinoza (1632-1677), Gottfried Wilhelm Leibniz (1646-1716), Pierre Simon Laplace (1749-1827), Georg Wilhelm Friedrich Hegel (1770-1831), Samuel Taylor Coleridge (1772-1834), and Friedrich Wilhelm Joseph Schelling (1775-1854). Scholars continue to reveal Bruno’s influence, since he was one of the first to set human action against its true background: the infinite.

• Gatti, Hilary. Giordano Bruno and Renaissance Science. Ithaca, N.Y.: Cornell University Press, 1998. Traces Bruno’s contributions to the scientific thought and practice of the sixteenth and seventeenth century, including ways he used non-mathematical forms of inquiry and fostered changes in mental approach to problems.
• Mendoza, Ramon G. The Acentric Labyrinth: Giordano Bruno’s Prelude to Contemporary Cosmology. Rockport, Mass.: Element Books, 1995. An authoritative, comprehensive, and multifaceted study of Bruno’s cosmological thought in the context of his own time and in the context of the twentieth century.
• Singer, Dorothea Waley. Giordano Bruno—His Life and Thought: With Annotated Translation of His Work, “On the Infinite Universe and Worlds.” Reprint. New York: Greenwood Press, 1968. Essential translation of Bruno’s work combined with a superb introduction to it as well as to his diverse intellectual and literary abilities.
• White, Michael. The Pope and the Heretic. New York: William Morrow, 2002. A narrative, biographical account of Bruno’s confrontation of the Roman Catholic Inquisition, exploring his originality, insistent and enthusiastic personality, and courage in the face of execution.

1462: Regiomontanus Completes the Epitome of Ptolemy’s Almagest

c. 1478-1519: Leonardo da Vinci Compiles His Notebooks

1543: Copernicus Publishes De Revolutionibus

1572-1574: Tycho Brahe Observes a Supernova

1580’s-1590’s: Galileo Conducts His Early Experiments

1582: Gregory XIII Reforms the Calendar

1600: William Gilbert Publishes De Magnete