Were there science fiction stories written during the Middle Ages (i.e., before circa 1500 AD)?
Joannes Kepler wrote a science fiction work called Somnium in 1609, an "interview with a knowledgeable 'daemon' who explained how a man could be transported to the moon" (source). However, 1609 was not the Middle Ages.
Medievals did ponder the possibility of intelligent extraterrestrial life, but did they write what we'd call science fiction?
I would say a good case can be made to answer 'yes' on this.
Per Wikipedia, "During the Middle Ages in the Middle East, foundations for the scientific method were laid by Alhazen in his Book of Optics." The site goes on to say, "Medieval science carried on the views of the Hellenist civilization of Socrates, Plato, and Aristotle, as shown by Alhazen's lost work "A Book in which I have Summarized the Science of Optics from the Two Books of Euclid and Ptolemy, to which I have added the Notions of the First Discourse which is Missing from Ptolemy's Book from Ibn Abi Usaibia's catalog".
Given optics was included as a branch of "science" during this time, I think it would be reasonable to consider a story which leverages the fantastical and advanced use of optics in a fictional setting as early 'science fiction'.
One such story was by Geoffrey Chaucer who included in the 14th century “The Canterbury Tales”, the story "The Squire's Tale". In the story Chaucer describes a mirror in which characters could see what was happening in faraway places and communicate with another such mirror in Rome. What distinguishes this mirror from other 'magical' items is that the device does not rely on a magical or religious operation. Instead, there is speculation by one character that the mirror was not "magic" but "an arrangement of angles and cunningly carefully constructed reflections". I.e. a "scientific" solution rather than magical.
And some of them marveled about the mirror, which had been carried up into the main tower, how one could see such things in it. One answered and said that it might well work in a natural way, through arrangements of angles and of cunning carefully constructed reflections, and said there was such a one in Rome.
Or as it appears in the original text:
They demen gladly to the badder ende. And somme of hem wondred on the mirour That born was up into the maister-tour, How men myghte in it swiche thynges se. Another answerde, and seyde, it myghte wel be Naturelly by composiciouns Of anglis and of slye reflexiouns; And seyden, that in Rome was swich oon.
The characters go on to relate the mirror to ancient philosopher/scientists as opposed to magicians and/or religious figures. Given that, I would argue that the characters are approaching the device in a way that speaks more to advanced technology (a.k.a. science fiction) than magic.
They spoke of Alhazen and Vitello and Aristotle, who wrote of curious mirrors and of perspective glasses, as they know who have heard their books.
Or again as written in Middle English
They speken of Alocen and Vitulon, And Aristotle, that writen in hir lyves Of queynte mirours and of perspectives, As knowen they that han hir bookes herd.
The Wikipedia site on science fiction also includes Ibn al-Nafis's Theologus Autodidactus in the 13th century as an early science fiction story.
The final two chapters of the story resemble a science fiction plot, where the end of the world, doomsday, resurrection and afterlife are predicted and scientifically explained using his own empirical knowledge of biology, astronomy, cosmology and geology.
Based on that and the example from Chaucer, I think we can reasonably say 'yes' to this question. That the intent of the authors in these stories would be to write in a manner consistent with what we could consider 'science fiction'. Namely again per Wikipedia:
"Science fiction is a genre of speculative fiction typically dealing with imaginative concepts such as futuristic science and technology, space travel, time travel, faster than light travel, parallel universes, and extraterrestrial life....It usually eschews the supernatural, and unlike the related genre of fantasy, historically science fiction stories were intended to have at least a faint grounding in science-based fact or theory at the time the story was created,
The question has a fundamental problem, which is an artificial separation of "science", "magic" and "religious miracle". Pre-Enlightenment, this separation simply did not exist. You'll recall that Newton spent much of his life trying to make alchemy work, and numerous other things which we today would consider "magic". Indeed it was the work of Newton, Hooke and all the numerous other "natural philosophers" which first defined the division between science and magic, and first started the Catholic church's problem with identifying miracles when cause, effect and evidence are better understood.
Productions of Macbeth typically have the witches as some kind of supernatural special effects, and modern audiences see them as such. For Shakespeare's audience though, this was as realistic as The Wire is for us. Most of us have never met a drug dealer or lived in those areas of Baltimore, but we know it exists and we've probably seen pictures. Shakespeare's audience knew witches existed, and most of them had probably seen a witch arrested, tried and executed.
In this context, separating "science fiction" and "magical fiction" becomes basically impossible. The Tempest could easily be considered science fiction, for example, because Prospero's magic is merely something that's a bit further ahead than the alchemists of the day could manage. Of course Shakespeare wasn't medieval, but he shows the limits of knowledge that still existed several hundred years earlier.
To demonstrate this further, consider the story of Jesus as a science fiction novel. A man is born by parthogenesis, is visited by aliens whilst a baby, is supernaturally intelligent as a child, replicates enough food for thousands of people, has a universal translator with direct stimulation of ears so that everyone hears in their own language, controls the density of matter to make water become solid, heals people, regenerates after a mortal injury, then finally teleports away from his friends after a last goodbye. If you want to fictionalise the story of Jesus or saints (and medieval people certainly did!), then whether all this comes from the Holy Spirit, magic or science is completely up for grabs from a modern viewpoint. (Clarification requested by KutuluMike - I'm not saying that the story of Jesus is fiction, just that key elements could be construed that way. In fact this forms the plot of Michael Moorcock's novel Behold the Man.)
My point is that separating science, magic and religion simply isn't possible with a pre-Enlightenment view of the world. Without any recognised differences between those categories when it was written, pre-Enlightenment fiction can't be nailed into any of those categories.
From the second century there is what is considered the first science fiction story:
"True History", Wikipedia
It contains robots, space ship fights, aliens, a trip to the moon and to the sun.
It's not medieval but it was stated that it should be pre 1500.
Not sure you want to count that as sci-fi, but there is Utopia (Thomas Moore, 1516)
It is a description of an imaginary place to illustrate what the author considers the best possible society. It deals a lot with how the human interactions are different and how that solves the problem the author's actual society struggles with, so it might be considered social science fiction.
Depending on how you define sci-fi, I would propose the Divine Comedy as medieval science fiction.
I define science fiction as a fictional story based on the most accurate view of reality of the time. In our day, with the domination of physical science, the most accurate view of reality is a purely physical system. However, in Dante's day, such a view included physical science, but also much more in the realms of philosophy and theology.
Another important part of science fiction is traveling out of our normal world into some fantastic realm. Dante also does this. He travels into the center of the earth, as in Jules Verne's sci-fi classic "Journey to the Center of the Earth", and Dante also travels into space, visiting all the known planets in our solar system.
Finally, sci-fi tends to make use of new technology. This is a bit lacking in Dante, but I wouldn't say completely absent. Once Dante goes into outer space, he gains the ability to teleport from one planet to another as he gains epiphanies. A little bit like the witches tessering in Madeleine L'Engle's sci-fi story "A Wrinkle in Time".
