Thread by @Helenreflects

I'm going to do a thread on Bernard De Fontenelle's Plurality of Worlds (1686), a series of dialogues between a Marquise and a philosopher that offers a startling and disorienting vision of a myriad of inhabited worlds 1/

I recommend listening to this subtle performance of Marin Marais' Voix Humaines while you read this thread, performed by Brandon Acker and Craig Trompeter 2/

We have dialogues over five evenings between a philosopher and a Marquise. At the time that de Fontenelle wrote, it was unusual to have a woman feature in a philosophical dialogue. Women were commonly thought to be inferior to men (in virtue, physical ability, intelligence) 3/

In 17th century France, a lot of discourse had turned openly misogynistic, deriding learned women as somehow silly or ridiculous. This was because men did not like the competition of women, esp wealthy female patrons of salons. Several of these were patrons to de Fontenelle 4/

The Marquise is clever, witty, a worthy conversation partner to the philosopher (the dialogue is written in first-person from the philosopher's perspective), but also has not had any astronomy lessons before, so a completely blank slate about this 5/

Not 100 years before, Giordano Bruno was burned at the stake for suggesting that there were multiple inhabited worlds. And Galileo also had an unpleasant brush with the inquisition only 50 years ago. So De Fontenelle was popularising for a wide audience something controversial 6/

Nina Gelbart's introduction to the 1990 translation of the book is very useful--see here. She sees the work as a popularization of early science, offering unique insights into science finding its voice, and De Fontenelle's optimism shines through. 7/

ucpress.edu/book/978052007…

De Fontenelle believed science would emancipate us from being slaves of our passions, would free us from ignorance and prejudice, would help us realize how nature is marvelous and interconnected (all major themes in the Enlightenment, the Encyclopedistes later on) 8/

De Fontenelle succeeded in his popularizing aims. The Entretiens sur la pluralité des mondes enjoyed enormous success. For instance, it was translated by the first female professional writer in England, Aphra Behn, just a couple of years after its publication in French 9/

Ok on to the Plurality of worlds itself. So it's five dialogues (later new editions and there were many, as I said this work was hugely popular, have a sixth dialogue added with some replies to objections but I am going to disregard that) 10/

In the Preface to the work, De Fontenelle explicitly makes the case for why a woman as interlocutor to the astronomy-knowledgeable philosopher (note that astronomy in the 17th century was still a part of natural philosophy). The aims are emancipatory and pedagogical 11/

He also very interestingly makes explicit that his work has to have literary qualities and refers to La Princesse Des Clèves, the earliest modern psychological novel and hugely influential. 12/
en.wikipedia.org/wiki/La_Prince…

Since Plurality of Worlds (spoiler) raises the possibility of alien life on myriad planets in myriad solar systems, De Fontenelle must address some theological thorny issues. Did these creatures fall? They're not children of Adam. De Fontenelle brushes these worries aside 13/

First evening starts with the Marquise and the Philosopher (the viewpoint character) strolling in her garden in a pleasant evening breeze. As they watch the moon and stars, he raises the possibility that "every star could well be a world". 14/

He thinks that because it is pleasing, and pleasure is part of truth. The Marquise then asks him to share this truth. He first declines, saying it's not enjoyment like comedy, she replies "Do you think I'm incapable of enjoying intellectual pleasures?" So he proceeds 15/

First, he offers an idea of what philosophy is. "All philosophy is based on two things only. Curiosity and poor eyesight".
Better eyesight = we would be able to discern what these solar systems look like
Lack of curiosity = we would not care about these solar systems 16/

He then likens nature to the back of an opera-house where you can see the mechanisms at work. She objects that this is very mechanical, but later says "Now that I know it's like a watch, it's superb that...the whole of nature is based upon such simple things" 17/

Then comes a discussion of why astronomy is such a great science to dabble in, as well as an exposition of the Ptolemaic old geocentric view. To arrive at his vision of myriad inhabited worlds, De Fontenelle eases the reader very gradually. 18/

He sings the praises of Copernicus, painting him as an iconoclast, as someone who put us in our place, away from the center of the universe 19/

He then explains how the Ptolemaic picture is all wrong and too complicated and explains Ptolemy's picture of sun, planets, the Earth just one of the planets and then comes a really charming, witty piece of dialogue that I include below to give a flavor of the work 20/

The Philosopher explains that people clung on to Ptolemy because they want to put themselves at the center (of the universe). The Marquise then objects, if that's right, how could we ever have accepted Copernicus (I imagine her as the brilliant, slightly terrifying student) 21/

Rest of dialogue taken up with questions about the atmosphere, the speed of the Earth revolving around the Sun, that's the end of the first Evening 22/

Second dialogue, as I said De Fontenelle eases the reader very gradually, warms them up to the idea of alien life. This one discusses chiefly the prospect of life on the Moon. A lot of cool stuff about what can be seen from telescopes (e.g., are there seas on the Moon)? 23/

De Fontenelle is not sure that there is life on the Moon because we don't know enough about it. But it's certainly possible. He then forwards the idea that lunar creatures would resemble Earth life, because nature creates both unity and diversity 24/

He compares this to the human face. There is a lot of diversity in faces but also a unified plan (individually, and across racial lines, there is quite some discussion of early race science in this book and it has aged OK esp compared to explicit racists like Hume and Kant) 25/

The Marquise expresses sadness that Europeans will once be able to meet the Australians, but we will never be able to meet the inhabitants of the Moon because travel to it is impossible. Heartbreaking 26/

3rd evening continues with the Moon. The philosopher reiterates he cannot be sure there is life on the Moon, and the Marquise finds this uncertainty hard to bear (another charming, witty piece of dialogue I reproduce below) 27/

Then we go on to Venus. Here the philosopher introduces a principle "Why not?" Why could there not be life on Venus? The Marquise objects: "Always by saying "Why not" are you going to put people on all the planets for me?"
The Philosopher: Yes, we can populate all the planets 28/

Marquise objects that it's hard to imagine all these alien life forms "My imagination is overwhelmed by the infinite multitude of inhabitants on all these planets, and perplexed by the diversity one must establish among them".
Philosopher says there is unity in diversity 29/

Fourth evening. The Marquise and the Philosopher speculate on whether the "why not" principle could give life on Mercury or on the Sun. They find that Mercury is possible (though very hot) but the Sun is impossible to hold life 30/

Fifth evening (sorry thread broken, now repaired). We've left the solar system and the Marquise and the Philosopher speculate on the possibility of life in other solar systems. When realization dawns, the Marquise expresses a sentiment very similar to Pascal: 31/

"here is a universe so large that I'm lost, I no longer know where I am, I'm nothing. Each star will be the center of a vortex, perhaps as large as ours? ... As many spaces as there are fixed stars? This confounds me--troubles me--terrifies me" (see also Pascal, Pensées) 32/

The philosopher's response to this is remarkable "This puts me at my ease. When the sky was only this blue vault, with the stars nailet to it, the universe seemed small and narrow to me; I felt oppressed by it. Now... it seems to me I breathe more freely, I'm in larger air" 33/

He then acquaints her to the idea o the Milky Way and the realization that it consists of thousands, millions of stars. Just like the Moon resembles Earth (see earlier Evenings), the Milky Way's stars each resemble our sun 34/

Next, they discuss the intriguing idea of stars coming into being and dying. Not long before, astronomers believed stars were eternal and unchanging, but the Philosopher argues that the "universe could have been made in such a way that it will form new suns from time to time" 35/

He offers this analogy: Imagine a gardener walking among the roses. Since roses live so briefly, each rose would say "Our gardener is eternal and unchanging", and they'd feel justified because no rose would've . In the same way, the ancients believed the stars eternal 36/

Anyway, then it ends. With love-talk (there is flirting throughout this story). It is such a delightful read I was happy to share this with you all /end

(addendum: if you enjoyed this and are into early modern astronomy--and who would not be, as it early modern astronomy simply delightful--you might also enjoy my earlier thread on Kepler's somnium, a very early SF story.

https://twitter.com/Helenreflects/status/1390875750203539456

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