The following is a small piece into how Bruno viewed the universe, how he believed planets and stars acted, and what he thought was out there, beyond Earth and our Solar System.
Europe in the 1500’s was a time of rich scientific development. In the field of astronomy, Copernicus came forward with his ideas of heliocentrism. Later in the century and towards the beginning of the next, philosophers like Tycho Brahe, Galileo, and Kepler would all make contributions towards the field, sometimes building on past ideas, other times creating different models all together. It is in this latter category that we find many of Bruno’s thoughts: a large part of his model of the universe was built from the ground up. Bruno’s model of the universe was “infinitely large,…in which every visible star was sun or planet like our own, each of which was populated with its own plants, animals, and people.” (Gosnell 2014). When looked at through the scientific lens of the 21st century, there are quite a few things that Bruno’s model gets right, and others it gets wrong. However, regardless of what he got “right”, it is certain that much of what he said went against the Aristotelian model of the universe and the cosmos; not only were the ideas contrary, but Bruno also wrote about his specific gripes.
The core of Bruno’s model is that of the infinite universe. While this is contrary to the Aristotelian model, it also would have been impossible. One problem lies in the idea of heliocentrism, which Copernicus and Bruno both subscribe to. If the Earth is moving around the sun, then it obviously cannot be stationary, like in the Aristotelian model. Additionally, Bruno does not agree with the “prime mover” idea, either. In essence, while the universe is infinitely large and contains infinitely many planets and stars, it is immobile. And, all of those celestial bodies within the universe move due to a force within them. “The earth moves and so do the other stars, according to their proper local differences, in virtue of an intrinsic principle which is their proper soul.” (La cena de la Ceneri). However, while he describes planets as having souls, he clarifies that they are not quite analogous to people. “If it has members, it has them not similar to ours; if it has flesh, blood, nerves, bones, veins, they are not similar to ours; if it has a heart, it is not like ours.” (La cena de la Ceneri). It is in this idea of planets being “alive” where Bruno finds an explanation for the movement of the planets. Bruno separates celestial bodies into two categories, fiery suns and watery planets. Suns produce light and heat, which is necessary for sustaining life; however, while life needs this light, Bruno also pushes the idea that the planets themselves have the desire for said light. Meanwhile, the suns absorb “vaporous exhalations” (Knox 2019) from the watery planets. Also, the water on planets is how we are able to see them; what we see is the light reflecting off the planets. In this regard, Bruno counts the moon as a planet, but acknowledges that it is a satellite of the Earth. He also hints at the idea that there may be other planets in our solar system that we cannot see, as some planets may have “water that does not face us, and the sun, which would act as a crystal mirror, which would receive luminous rays, rendering it visible.” (De I’Infinito, Universe, E Mondi, 102). So then, the lights in the skies, are we observing planets reflecting light or suns creating it? Bruno says it is the suns, as “they are far larger, the largest of bodies”.
Bruno argues that an infinite universe and finite one are not inherently more logical than the other, in that either one should and must be justified. Bruno mainly argues against the “prime container” idea of Aristotle. A key point that Bruno makes repeatedly is that of relative position. For example, when we look into the night sky and see a small speck of light, while it may appear to be small to us, that is because that body is relatively far. According to Bruno “location is no other thing than the surface and extent of the contained body.” (De I’Infinito, Universe, E Mondi, 36). In essence, there is no absolute position; an object’s position is defined as its position relative to other bodies in space. Therefore, if the prime container contains everything, including itself, and there is nothing outside the prime container, then where is it? Bruno’s answer is that it has no position, and that it is nowhere. By extension, everything in it has no position, whether that be me, you, the Earth, or the stars.
The Earth that we inhabit to Bruno was not exactly super special. The reason for this was twofold: 1) there are many other earths (watery planets) out there and 2) they are all capable of having life and 3) a lot of them do have life (some of it intelligent). Therefore, there were all sorts of aliens out there, from nymphs, to demons, to troglodytes. In addition to this, Bruno does not rule out the idea that the suns are inhabited. When one character from a dialogue poses the question “What animals could live in fire?”, the response is that even though the suns are quite fiery, they are not all fire, in the same way that the Earth is not solely comprised of water. To build on the last point, remember that Bruno believes the only reason why the Earth would be visible to someone on the Moon for example would be because of the oceans; so, perhaps our Sun had fiery parts and less-fiery parts. In the same way that humans would not exist in the same way we do know if the Earth was totally flooded, there could be beings that could live on a fiery planet, just not in the fire itself.
While Bruno had many ideas that do not hold up to modern science, the fact that he was able to come to some of the conclusions he did is still extraordinarily impressive. Namely, the vast size of the universe (which we still do not fully comprehend), the concept of subjective vs objective position, and the possibility of life outside of Earth.
References
Primary Sources:
Bruno, Giordano. The Ash Wednesday Supper: (La Cena De Le Ceneri). The Hague: Mouton, 1975.
Bruno, Giordano, and Scott Gosnell. On the Infinite, the Universe, & the Worlds = De L’infinito Universo e Mondi. United States: Huginn, Munnin & Co., 2014.
Secondary Sources:
Knox, Dilwyn. “Giordano Bruno.” Stanford Encyclopedia of Philosophy. Stanford University, May 28, 2019. https://plato.stanford.edu/entries/bruno/.