I recently finished reading Galileo Galilei’s (1564 – 1642) Dialogue Concerning the Two Chief World Systems, a treatise on geocentric and heliocentric astronomy. Published in Italy during the February of 1632, the Dialogue was both revolutionary and controversial for its time – earning Galileo a condemnation at the hands of the Italian Inquisition, and a life-long house-arrest that lasted until his death. But yet, despite it’s contemporaneous infamy – it’s valid to ask ourselves:
“Why are the Dialogues relevant today? What can we gain from reading it?” As a purely scientific work of observational astronomy, the Dialogues would only be relevant as a matter of historical interest. It may be a milestone or a landmark in the studies of the history of science, but heliocentrism as a doctrine is neither new nor controversial today. For a book to be considered perennial, it generally has to touch upon some truth or thesis that is universal to the human experience – to transcend the material (and ephemeral) circumstances of it’s historicity. That’s why the Iliad, with its themes of rage and justice – is just as valid and relevant today, as it was during the days of Homer. But as a work of scientific non-fiction, it is not readily apparent how Galileo’s Dialogue has appeal to universal validity – when the subject-matter of the treatise itself is a field which has advanced in the 400 years since. Why do we read Galileo’s Dialogues? To what extent can it teach us, as students of a culture nearly four centuries antecedent to Galileo’s death? These were the questions that puzzled me, as I engaged in a month-long preceptorial of the Dialogue with my colleagues.
The Dialogue Concerning the Two Chief World Systems is an unusual work for a scientific monograph. The Dialogue is first and foremost, a dialogue. Set as a conversation between Salviati, Sagredo, and Simplicio, the three characters meet over the course of four days, and converse amongst themselves like characters in a play. The book is organised not by subject or theme, but chronologically – literally divided into four days: Sagredo and Simplicio arrive Salviati’s house in the morning – and refreshments are served at the afternoon, when the hot Venetian summers conclude the conversation. Yet, despite its casual form, Galileo’s work is a serious, empirical presentation of the merits of Heliocentric astronomy, complete with geometrical proofs and demonstrations – accoutrements of the highest rigour by the standards of Renaissance science. Why did Galileo choose the form of a dialogue for his presentation? Was the structure of the dialogue essential to Galileo’s demonstration, or only an incidental trapping of fancy and style? Modern authors have flirted with different forms of presentation for scientific inquiry, after all. Shalev Ben-David’s 2017 paper on quantum cryptography featured an abstract in the form of an Aesopian fable, and Rovelli’s Dialogue on Quantum Gravity even re-imagines the familiar characters of Salviati, Sagredo, and Simplicio in the cafetaria of an American university. The key difference, which I realised as I immersed myself in Galileo’s treatise – is that its formal nature as a dialogue is not incidental to its presentation, but rather essential to the very philosophy of scientific inquiry that Galileo’s Dialogues embody.
What do I mean by philosophy of scientific inquiry? Does a work of academic literature necessarily embody an underlying philosophy at all? I think it is fairly uncontroversial to claim that all forms of inquiry must assume some wider set of principles or axioms which serve as a foundation for its study – even if such a philosophy is unstated, and as omnipresent as the water to which a fish calls home. To quote Sartre, “If any metaphysics presupposes a theory of knowledge, it is equally true that any theory of knowledge presupposes a metaphysics.” And as a philosophy of scientific inquiry, these underlying assumptions define the ways we gather knowledge, the ways we reach valid truths. The claim of my essay is that in our study of Galileo’s Dialogue, we come to a better understanding about the philosophy of scientific inquiry. Not just a method of scientific inquiry in the Renaissance, or the particular scientific inquiry as it was conducted by Galileo – but scientific inquiry as we know it. I cannot apodictically assert whether Galileo’s Dialogue Concerning the Two Chief World Systems was the first presentation of the scientific method, but it is decidedly the most influential example – and it’s publication, controversy, and subsequent condemnation set the stage for the development of science as a distinct field from Philosophy and Theology.
What is this philosophy of scientific inquiry which Galileo’s Dialogue embody? In order to answer this question, we must start by taking a look at the text itself. Galileo’s dialogue is the gathering of three close friends at Sagredo’s house, in the midst of a hot Venetian summer. The book prefaces the beginning of the first Day with the following:
It has happened that several discussions had taken casually at various times among these gentlemen, and had rather whetted than satisfied their thirst for learning. Hence very wisely they resolved to meet together on certain days during which, setting aside all other business, they might apply themselves more methodically to the contemplations of the wonders of God in the heavens and upon the earth. They met in the palace of the illustrious Sagredo; and, after the customary but brief exchange of compliments, Salviati commenced as follows.
Following that introduction, we meet the three characters. The worldly and successful Salviati, listens actively and with admiration, as his friends Sagredo and Simplicio take on the roles of advocates for the titular “two chief world systems.” Sagredo is presented to us as a keen and sophisticated advocate for heliocentrism, substantiating his claims with both experiments and geometrical demonstrations. Simplicio takes on the mantle of the Ptolemaic geocentric model, quoting learnedly from Latin as he supports his claims with Aristotelian doctrine.
I admit, for the longest time I could not understand the character of Simplicio. At first, knowing his role as the speaker for geocentricism – my perceptions of him were coloured by the fact that he was the proverbial Devil’s advocate – the very absurdum in the reductio ad absurdum that the work seemed to be. Biased by my modern sensibilities of universal gravitation, Simplicio’s quaint, spirited quotations from Aristotle seemed like hidebound dogmatisms. In brief, my perception of him was summed up by his very name: a Simpleton. How could his interlocutors not feel the my same feelings of frustration, as they argued with him over the course of several days? His dogged following of Aristotelian physics, and the way he reluctantly and begrudgingly conceded points only after rigorous argumentation, made him appear foolish and asinine. Was Simplicio’s very inclusion in the text, merely a rhetorical strawman, a personified concession to the Church?
It was only much later, did I realise my misjudgement of Simplicio’s character – and his place in the dialogue. Simplicio’s no simpleton – but rather, he is a young man trained and educated by the finest standards of Classical education in the Italian Renaissance. Named after Simplicius of Cilicia, a noted Neoplatonic commentator and scholar; Simplicio quotes and refers to Aristotle with a scholastic fluency worthy of his namesake. The arguments that Simplicio makes in refutation of Heliocentricism may appear unusual to our modern-day empiricism – but they are entirely consisted with an Aristotelian system of physics and substance. Simplicio is not a simpleton. If anything, his comprehensive and intimate knowledge of Aristotle would earn him a professorship in the Classics department of any University in the world today. I had misjudged Simplicio’s character out of no advantage other than the benefit of hindsight.
So what is the role of Simplicio in Galileo’s Dialogue? How does he fit in the rhetorical narrative of the work as a whole? I think it is perhaps my own initial misunderstanding of Simplicio’s character, which may best shed light on Galileo’s underlying method. We are all products of our environment, our path a trajectory of the sum of the forces acting upon us. And it is my own bias, as a member of a face-paced, results-oriented society – to be interested only in the answers, and not the process that leads us to them. Simplicio is wrong, empirically speaking – the Earth is not the center of the universe, nor the Sun a satellite of our globe. But Galileo’s Dialogue is not a mere presentation of facts as they stand – but rather, a work that presents the scientific method, as a process of discursive inquiry.
Science is fundamentally dialectical in nature, where findings are not totems of authority to be appealed to – but components of a longer, overarching conversation – a dialogue between scholars and scientists as the field progresses. It would be unthinkable for a modern Physicist to base their findings on naught but the authority of Einstein – but such a underlying conception of science as an empirical pursuit was not always the case in our past. A Natural Philosopher of the 15th century can publish a paper explicating the aetiology of a novel phenomena based solely upon the authority and dogma of Aristotle, and such a work would be considered a valid method of inquiry. Its merits would be analysed on the validity of the interpretation alone.
Galileo’s Dialogue is a proposal and demonstration, of an alternative system. Where the validity of any unit of scientific truth is not assessed based on its consistency with established authorities – but on empirical experiments and demonstration. More importantly, Simplicio’s role in the dialogue is to illustrate the discursive role of scientific inquiry in action. Sagredo presents his arguments to Salviati, and Simplicio in turn – and Salviati plays his own role in the resulting synthesis of thesis and antithesis. As key players in this dance of scientific inquiry, the characters embody qualities required for the very process to work.
What are these qualities? Sagredo, Salviati, and Simplicio are many things – they are educated, leisurely, perhaps even aristocratic. But the theme that was most present on my mind, as I worked through the Dialogue, as the fact that all three characters – despite their differences – are friends. Friendship: or at the very least, a good-natured benevolence and goodwill – seem to be amongst the essential qualities necessary for the discursive process of inquiry to work. Throughout the dialogue, no matter how much the characters disagree with each other – an atmosphere of good faith and understanding prevails. Simplicio may misunderstand the reasoning of Sagredo, but his friends are quick to correct him. And despite his own dogged nature and faith in Aristotle, Simplicio does accept the counterarguments of his friends, and profess the need for further study and contemplation, with every concession that he makes. This genuine friendship between the three characters – is more than just a narrative scene-setting or facade. They are truly friends. Salviati and Sagredo fret and worry over their companion, when he shows up late to their meeting due to the tides. And likewise, Sagredo, who leans towards the side of Salviati’s arguments throughout the work – is quick to spring to Simplicio’s defense, when Salviati misunderstands or critiques Simplicio on unfair grounds.
In conclusion, as I read Galileo’s Dialogue Concerning the Two Chief World Systems, I realised that there are many lessons to be learnt from it – that are valid not just in it’s own historical context, but universally valid today. The Dialogues are a great presentation of the scientific system – a process and method of inquiry based on neither Gods nor Man, but evidence alone. And it is a heartening and sincere rendition on the necessity of goodwill and friendship, in the process of any intellectual inquiry. There are many things that I had wished to address in this essay which I ultimately left unspoken, due to a lack of time of my own. But I would like to conclude with the following passage from the latter half of the Dialogue:
Salviati: “Sagredo, please let us weary ourselves no longer with these particulars, especially since you know that our goal is not to judge rashly or accept as true either one opinion or the other, but merely to set forth for our own pleasure those arguments and counter-arguments which can be adduced for one side and for the other.”
Let us remind ourselves that Sagredo, Salviati, and Simplicio – busy individuals with personal and professional lives full of happenings of their own – agreed to take a break from their worldly affairs, and set aside four days amongst themselves for a philosophical discussion. During which, the friends argued not for profit, or even to necessarily change each other’s opinions. But rather gathered in the company of each other’s friendship, to set forth opinions and arguments for the sake of the pleasure of inquiry alone.