To what extent did the trial of Giordano Bruno set a precedent for that of Galileo?

“If one regards [The Ash Wednesday Supper] as an exposition of the Copernican system together with some other scientific topics”, one finds what “appears to be a compendium of nonsense -- a disorganized display of gross error connected by incomprehensible passages.”1 Many, due to the presence of some kind of Copernicanism, have tried to tease a tortured scientist out of Bruno’s principal work, to find in him a silenced Galileo. Such a reading suggests that the outcome of Galileo’s trial had its precedent in this misunderstood man with few sympathizers, burned at the stake for ideas before his time. The ultimate failure of this reading gave way to readings placing him exterior to logic, “exposition”, “science”, and faithful reproduction of Copernicus; and rather emphasising Bruno’s concern with his own philosophical system. Being far more exclusive to Bruno, they leave the question of precedent for Galileo’s trial unanswered. Here, I attempt to demonstrate that the fates, if not the philosophical systems, of these men were still connected. This, I argue, is precisely due to the contemporary mistaken connection between them both.

The relationships between the trials of Bruno and Galileo, and between the men themselves, have been much debated, with reference to the emergence of modern scientific method and their respective defences of the Copernican model. A pivotal point is Frances Yates’s classic study of Bruno and his relationship with Hermeticism. Prior to this, Bruno was predominantly treated as “the great rational champion of Copernicus”3, as a ‘martyr for science’, and was paralleled with Galileo. Yates, however, allies Bruno more closely with “the occult philosophy,” by which she means “Hermeticism as revived by Marsilio Ficino, to which Pico della Mirandola added a Christianised version of Jewish Cabala”.4 She contends that Bruno’s Copernicanism was adopted not on the empirical grounds attributed to Galileo, but because its heliocentrism was agreeable with the Hermetic writings and with the ancient Egyptian divinity of the sun. Indeed, it is evident that Bruno misunderstood the Copernican model, and scorned mathematical models in general.5

Many other kinds of comparative study are possible.6 However, our specific relation -- “precedent” -- has specific implications. It is primarily a legal term, which demands us first to ask: who we are taking as prosecutor? Most specifically, Cardinal Robert Bellarmine, who served in both trials? Or the Inquisition, specifically the Roman Inquisition, which conducted both trials? More generally, the Roman Catholic Church? Or even, as both trials “generated a subsequent cause célèbre7, as wide a body as ‘public opinion’? I choose to focus on the inquisition (with a small ‘i’8).

Nor is it clear how strict is the term “precedent.” Its strongest, legal, implication is that the trial of Galileo relied consciously upon, and judged with direct reference to, the trial of Bruno. The connection between the two men is not strong enough for us to look for this. Less strictly, though, we can ask: what is there about the aspects of the trial of Bruno which has a causal impact upon the aspects of that of Galileo?

Nor it is not clear what aspects of the trials we are considering. It is mundane to compile a list of arguable themes that have common elements in both trials.9 The conflict, however, must be in terms of which the historical actors were conscious. I wish to confine this essay to the attitude of the inquisition towards that body of ideas that came to be known as “Copernicanism,”10 present, if in different ways, in the men of both trials. Hence I ask: what attitudes towards Copernicanism crystallised in the trial of Bruno which had causal impact on the results of the trial of Galileo?

Prior to Yates’s work, the assumption that Bruno had a similar world-view to Galileo, or that he was some kind of ‘proto-Galileo’11, allowed an easy answer to this question with few qualifications. Sir George Clark, for example, only wrote that, in contrast to Galileo’s trial, “[s]cience had its martyrs in the sixteenth century, but most, if not all, of them meddled in theology.”12 With Yates, Bruno is no mere scientist with theology-meddling tendencies, and we must re-analyse whether there are any connections between the trials at all.

More, following Yates’s work, many have demonstrated that Bruno was not even executed primarily for Copernicanism. The first alternative candidate for this position is the Hermeticism that Yates demonstrates. For it directly challenged the authority of the Scriptures: first by assuming the equation of age and authority, and second by assuming Hermes as contemporaneous with or even as antedating Moses, traditional author of the Torah. “Egyptian wisdom was not only earlier than Moses, but actually superior to that of the Jews as codified in the Bible”; it was “the true faith, not just the ancient theology that foreshadows Christianity.”13 This opinion manifested itself in at least two accusations against Bruno.14 Finocchiaro disagrees with the analysis of Hermeticism having any serious play in the trial.15 He does not, though, revert this “root cause” to Copernicanism, but finds it in “religious and theological topics”.'16 It is easy to reel these off: that Bruno “spoke ill of the Catholic faith, Church, and officials”, “held erroneous opinions on the Trinity, the divinity of Christ, and incarnation”, and so on.17 I readily accept that specific religious heresies were the most immediate cause. However, I do not feel that these contradict a Hermetic presence. Rather they were largely made possible by it: the downgrading of Scriptural authority naturally brought with it these religious heresies.

On this analysis -- that Bruno and Galileo held different beliefs, that where similar beliefs were held it was for different reasons, and that their trials were concluded on different grounds -- it is tempting to conclude that there was no causal relationship between the two trials. However, let us continue with a superficial analysis of their connection. There are many curious superficial similarities between Galileo and Bruno, and between their works, which would have been apparent to contemporaries. Galileo’s Dialogue and Bruno’s Ash Wednesday Supper (where he gives his exposition of his Copernicanism) both stuck to ambiguous modes of writing, imbibing the text with multiple meanings (or the suspicion of such). Both men “maintained that the Bible often speaks according to the common understanding of the people, and in so doing it may actually say things that are not literally true.” Both texts are in the form of dialogues. Galileo’s Copernicanism is discussed in non-mathematical, popularist language, and is thus even more easily confused with Bruno’s. The beliefs of both men had political stances (Bruno “was convinced that a monarch inspired and enlightened by Hermetism could lead the world into a golden age”18; Galileo was politicised by unfortunate association with Tomasso Campanella).19

These superficial similarities are, of course, correspondences, mere correlation. However, by this very fact, they are causative: the above similarities were recognised as such by contemporaries, and these were enough to bring Galileo into suspicion. This was for two reasons. First, they associate the words of Galileo with those of a condemned man. Second, and more particularly, the ideas of Bruno were greatly feared at this time, as they were associated with real or imagined Rosicrucian subversion, and thus there was a heightened level of alertness to them.20

The most important correlation, however, is that old fact: both men self-identify, explicitly or implicitly, as Copernican. This has causative effects in the same way as above: their self-identification transfers readily to the minds of the inquisitors, in which the Copernicanism of Galileo and Bruno, while different in origin, become recognised as the same body of ideas. However, in this specific case, we may assert a more specific causal connection. Here, we can find a connection of Galileo not just to Bruno the man, or to Brunonian ideas -- but to Bruno’s very condemnation and execution. Did Galilean Copernicanism have a precedent for condemnation in the condemnation of Bruno? There is every reason to believe that this question was being asked at the time. The Roman Catholic Church, and the Inquisition itself, were precedent-based systems,21 and poorly suited to empirical modes of evidence and non-scholastic modes of demonstration (Bellarmine’s numbered lists smack of scholasticism).

The immediate response to this is that Bruno was not executed for his Copernicanism: this can be interpreted to mean that Bruno was not associated with Copernicanism, or that it can be completely delineated from, and thus eliminated from, his body of heretical ideas. This is an over-simplification. Copernicanism, while in a minority position, occupies a significant place in the charges against Bruno.22 He was also publicly known as one of few outspoken supporters of Copernicus. I wish to show that Copernicanism cannot be clearly delineated from his other ideas: that his body of ideas was a web which, to a certain extent, stood or fell together. In so doing, I wish to show that Copernicanism at the time of Galileo’s trial did not simply by association link him to a condemned man, but implied that he held the very ideas for which a condemned man was executed.

As previously shown, Bruno’s Hermeticism was a chief reason for his condemnation. It was also closely associated with his Copernicanism, both in the eyes of Bruno and those of the inquisition. Bruno’s Hermetic universe was infinite -- for the infinite power and knowledge of God could not create something finite. Heliocentrism suited this infinite universe, primarily because it necessitated huge distances to account for the lack of observed stellar parallax. Bruno’s universe was fully animistic. Heliocentrism suited this too, for it asserted that even hulking celestial bodies could move at their own will. His universe was also one of unity and of infinite worlds -- incompatible with the idea of sub- and super-lunary spheres, which were also removed by heliocentrism. More, Bruno’s Copernican Hermeticism reflected badly on Hermeticist Copernicanism. It called attention to Copernicus’s rhetorical usage of it: “For, the sun is not inappropriately called by some people the lantern of the universe, its mind by others, and its ruler by still others. [Hermes] the Thrice Greatest labels it a visible god ...”23

I have already demonstrated the link between Hermeticism and Bruno’s religious heresies. It was through this that Copernicanism could also be associated with Bruno’s religious heresies; the immediate cause of his demise. An analysis of Bruno showed that Copernicanism could be put to this heretical use, and while not dangerous per se, was so in potentiality. There was a common awareness of this. Tomasso Campanella for example, in his 1622 Apologia, is very careful to state that his heliocentrism must be dissociated from Bruno’s heresies, which he took pains to condemn.24

We can thus claim that the condemnation of Galileo’s Copernicanism had significant precedent in the proceedings of Bruno’s trial. I have restricted myself to a demonstration only of this. I do not, however, claim it to be a sole or majority cause of the trial of Galileo, and many other causes have been discussed at length elsewhere.25 Nor by isolating these two trials do I claim any exclusivity for them; the Inquisition conducts investigations of many, before and during this period, in which similar patterns can be drawn.26

The view of Bruno and Galileo as ‘martyrs for science’ will not stand. Nor, however, will a complete separation of the two men. It may seem that, by reconnecting the trials of Bruno and Galileo after their disconnection by scholars such as Yates, I am reviving the old view that in Bruno’s trial there was a precedent for the “martyrdom of science”. Almost the reverse: I suggest that in Bruno’s trial there was a precedent for the damnation of various theological and decidedly un-scientific philosophical beliefs, a precedent which was mistakenly applied in the case of Galileo. They are causally linked via their respective trials under the Roman inquisition. Many superficial similarities, plus a particular political climate, aroused suspicion towards Galileo’s thought. The most important similarity was Copernicanism: here, Galileo was not just linked to a condemned man via casual association, but to condemned ideas via the precedent of Bruno’s theological heresies and the indissoluble unity of Bruno’s body of thought. Bruno, in order to support its ideas of spatial and temporal infinity, animism, and pluralism, welded Copernicanism to his condemned Hermeticism, and consequently also to his theological heresies. By general affirmation of the consequent, Copernicanism could afterwards not be seen independently of these condemned ideas. Thus, when Galileo “[takes] the Copernican side in the discourse,”27 he simultaneously can be seen to take the side of Hermeticism, magic, Rosicrucianism, and precedented theological heresy.


  1. Lawrence S. Lerner and Edward A. Gosselin, “Galileo and the Specter of Bruno”, Scientific American, vol. 255, no. 5, November, pp. 116–123. p. 116.
  2. Frances Yates. Giordano Bruno and the Hermetic Tradition. Routledge Classics (2007) (1st ed., Routledge & Kegan Paul, 1964).
  3. David S. Katz. The Occult Tradition: From the Renaissance to the Present Day. Jonathan Cape (2005), p. 29.
  4. Frances Yates. The Occult Philosophy in the Elizabethan Age. Routledge & Kegan Paul (1979).
  5. In particular, Bruno appears to place the Earth and Moon on the same epicycle-deferent combination, at diametrically opposite points on the epicycle. He does the same with Mercury and Venus. This model is neither physically nor observationally equivalent to that proposed in Copernicus’s De Revolutionibus. (Ernan McMullin. “Bruno and Copernicus”, Isis, Vol. 78, No. 1. (Mar., 1987), pp. 55-74.)
  6. Maurice A. Finocchiaro. “Philosophy versus Religion and Science versus Religion: the Trials of Bruno and Galileo”. Giordano Bruno: Philosopher of the Renaissance (ed. Hilary Gatti), Ashgate Publishing (2002); pp. 51–96. Finocchiaro suggests many different aspects of this relationship in pp. 51-52.
  7. Ibid., p. 52.
  8. That is, in contrast to ‘The Inquisition’, a term “often either personified and endowed with a diabolical omniscience or made to stand for a central intelligence agency with headquarters at the papal curia.” I use ‘inquisition’ to refer to the arm of the Roman Catholic church that dealt with heresy and punished contradiction of official doctrines, a term inclusive of the period before the sixteenth century in which there was never a permanently constituted congregation and tribunal of inquisition against heresy". This is as I do not wish to confine myself (Henry Ansgar Kelly. “Inquisition and the Prosecution of Heresy: Misconceptions and Abuses”, Church History, Vol. 58, No. 4. (Dec., 1989), pp. 439-451. p. 439–440.)
  9. For example, opposition to new ‘physicalist’ astronomy; questioning of the Scriptures, on matters sacred and profane; perhaps “the transition from the medieval and humanist experience of madness to our own experience, which confines insanity within mental illness” (Michel Foucault, Madness and Civilization: A History of Insanity in the Age of Reason, Routledge Classics (2001) (1st ed., Librairie Plon, 1961), p. xiii). The Inquisition’s attitude to madness has been explored with respect to the trial of Tommaso Campanella, “the last of the line of Italian Renaissance philosophers, of whom Giordano Bruno was the last but one” (Yates, Giordano Bruno, p. 394). See Joseph Scalzo, “Campanella, Foucault, and Madness in Late-Sixteenth Century Italy”, Sixteenth Century Journal, Vol. 21, No. 3. (Autumn, 1990), pp. 359-372.
  10. I am not using “Copernicanism” as synonymous with “heliocentrism” (which I would take as a component of Copernicanism). For my purposes here, I use it to describe any system which seems to identify itself as “Copernican” -- thus I describe Bruno’s and Galileo’s models, despite their differences, as Copernican.
  11. A term used in Lerner and Gosselin, op. cit., p. 116.
  12. Sir George Clark. Early Modern Europe: from about 1450 to about 1720. Oxford University Press (1975; 1st ed. published in The European Inheritance, 1954). p. 112.
  13. Katz, op. cit. p. 30.
  14. Finocchiaro, op. cit., p. 58. Implicit downgrading of Moses’s authority is consistent with accusation 14, “that he had spoken ill of Moses”, and more generally accusation 15, “that he had spoken ill of the prophets”. For numbering of Bruno’s accusations, Finocchiaro follows: “Firpo, Luigi (1993), Il processo di Giordano Bruno. Ed. Diego Quaglioni. Rome: Salerno Editrice.”
  15. He states that “Hermeticism and magic cannot be plausibly said to have been a main reason for his condemnation, let alone a root cause.” (Finocchiaro op. cit., p. 79.) I believe Finocchiaro to be mistaken. His analysis is based on a purely quantitative approach: counting the numbered accusations, thus reducing Hermeticism to a one-tenth importance of the proceedings. He rightly states that “there was not much talk of Hermeticism and magic in the proceedings of Bruno’s trial” (Ibid.) If one was to ask the inquisition for Bruno’s ultimate crime, Hermeticism would not be the answer given: Finocchiaro’s approach is useful in revealing the immediate state of mind of the inquisitor. It cannot, however, say anything of “root causes.”
  16. Ibid., p. 79.
  17. Ibid., p. 56. He also apparently held erroneous views on “the facts of Jesus’ life and death”, “on transubstantiation and on the holy mass”, and he “denied the virginity of Mary”.
  18. Lerner and Gosselin, op. cit., p. 119.
  19. Ibid., p. 119-21.
  20. Ibid., p. 119.
  21. All the more so following the Council of Trent (1545-63), which “confirmed [...] that religious truth derived from Catholic tradition as well as from the Bible.” (Norman Davies, Europe: A History, Pimlico (1997), p. 497.)
  22. Again taking the numerical list compiled by Firpo and used by Finocchiaro, Copernicanism can be obviously linked to: “(5) the existence of a plurality of worlds and their eternity”, “(31) The universe in spatially infinite”, “(32) there exist an infinite plurality of worlds” (again), “(35) the earth moves with the several Copernican motions”, “(36) the stars are animate, that is, possess rational souls”, and “(37) the earth is animate, that is, possesses a rational soul”. (Finocchiaro op. cit., pp. 56, 61.)
  23. Nicholas Copernicus. De Revolutionibus Orbium Coelestium. English tr. Edward Rosen, accessed 4th February 2008.
  24. Yates, Giordano Bruno, 418. “In 1622 Campanella published an apology for Galileo in which, when speaking of others who have defended Copernican heliocentricity and the movement of the earth, Campanella mentions Bruno as one of these other defenders, adding that he was heretical [...] Campanella is being careful to dissociate himself from the full implications of Bruno’s Copernicanism [...] It had to be [...] made clear that heliocentricity as a portent of a new age, and as integrated into a new theology did not mean for Campanella at this stage in his career, acceptance of all Bruno’s heresies.”
  25. Lerner and Gosselin op. cit., for example, are detailed on the political causes of Galileo’s trial.
  26. Scalzo op. cit., and Yates, Giordano Bruno, ch. 20, are instructive on the trial of Campanella.
  27. Galileo Galilei. Dialogue Concerning the Two Chief World Systems. English tr. Stillman Drake; annotation and condensation, S. E. Sciortino., accessed 4th February 2008.


Originally written as an essay in my History undergraduate for the Telescopes and Microscopes module at the University of York.

Tagged #giordano-bruno, #galileo, #copernican-revolution, #hermeticism, #early-modern-period, #renaissance, #science, #philosophy, #history, #essay.
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