What is the Physical Structure of the Mythic Earth System?
Flat: Jerusalem likely center of the world (may have Aristotalean spheres)
Round (Eratosthenes); Geocentric with crystal spheres (Aristotle, Ptolemy)
Round; Heliocentric (Aristarchus), but with crystal spheres (Aristotle)
Round, Heliocentric, planetary system (Democritus, Aristarcus; Aryabhata)
Other (Specify)
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I'm curious what everyone thinks the physical structure of the Mythic Earth world and system might be.
I've tried to outline the three or four major options available in the time period. Option #4 (Round, Heliocentric, planetary system) is essentially what exists in the real world. It was posited since at least the time of Democritus and Aristarchus, and contributions from Aryabhata in India at the turn of the 6th Century B.C.E. (his work was known to the Arabs and translated into Latin in the 13th Century as the "Aryabhatiya"), who described elliptical orbits and the Earth's axial tilt more than a thousand years before Kepler. For an anachronistic reference, it is also what Galileo observed. Note that Option #3 could include some of the same features, but definitely incorporates Aristotalean spheres as physical entities.
Due to the observed existence of entities associated with the "spheres", Option #4 allows for the coexistence of them as metaphysical objects, though not as physical components of the system.
Other is a catch-all category for everything from astrocheloneons to flat and bounded by the World Serpent to just about anything else one might choose to reasonably describe.
All of the options I described were based on models which existed by the 13th Century. Ergo, there would be observational data to suggest those based on empirical study instead of just pure philosophical "reason".
As Isaac Asimov once wrote, "Any interpretation of reality is correct if you choose the right postulates" (that's his approximate phrasing).
Aw man...those polls close too soon! I rarely have time to spot them and vote.
Anyway, the results concur with my own oppinion, so I'm satisfied on the grander level. And happy to see, that my missing vote would not have flipped the result.
Hilly, covenant at the centre ... twilight around the edges.
what else matters?
Seriously, though, mages will have access to classical texts (Eratosthenes, et al) and so will know all the scientific evidence that exists for the Earth being the shape it is (as in A&A or whatever shape the storyguide wishes to inflict on his players) ... they will believe that or -- being mages -- not.
Whatever the truth of your gameworld, the Church will, as is their custom, preach something different and say that anything else is heresy. Mages with no axes to grind will probably say "Yeah, whatever" to that, and go back to their studies rather get caught up in a pointless conflict in which they have no real interest.
I would like to add that the question of whether the Sun revolves around the Earth or vice versa does not mean anything in any absolute sense.
It is easier to do astronomical calculations if we assume that the Sun is at the centre for calculation purposes. But the calculations can still be done with other assumptions, its just more work.
The formal position of the Church in 1220 is that the world is a sphere. Indeed, one of the popes, Sylverster II, built a globe of the earth and kept it in his offices.
The world is flat thing is an Americanism. Not to bag Americans -at all-, but it is tracable to a particular book that was widely circulated in America as part of their development of their narrative of statehood.
The Church are not, in this instance, the regressive force you suggest.
I have recently read that it was an English invention from the time of the Enlightenment, a part of a counter-Enlightenment (fundamentalist-like) movement. Can't find the quote, though.
At any rate I think having the world be flat with Jerusalem at the center is just cooler, so that's how things are in my ME in any game I run
You mean in the real world? No, I don't think so. The situation is topologically different, and earth is accelerating while the sun is not; my General Relativity is rusty, but if I remember correctly these things are real, they (or something corresponding to them) will be true in any coordinate system.
I do not understand what you mean by "earth is accelerating".
Nor am I sure why relativity would make a difference - surely from that perspective any point can be selected as "central", some are just more convinient (for us) than others.
A historical note - just as the Church condemned Galileo, they also switched to using his math for astronomical calculations. They just insisted that in "reality" the Earth is in the centre. There is no scientific way to show that this is wrong - I mean, what kind of experiment could be possible here. My point being that the claim about which is in the centre is a claim about human perception, not about "reality".
(Didn't Bertrand Russell write something about this?)
Disclaimer - I am a engineer with some decent physics background. In other words, a complete geek.
Physics. Anything but a constant velocity, constant direction motion implies there is an acceleration somewhere. In the case of orbital mechanics, it is an acceleration towards the center of mass of the system. The mass ratio between the Sun and the Earth means that the center of mass is within the Sun (which barely wobbles), so the Earth is constantly accelerating towards the Sun, which is why it revolves around it rather than flying out into space at its current tangential speed, like a stone from a slingshot .
Not all frames of reference are equivalent, particularly when acceleration is involved. Once you bring in General Relativity, things get even messier with effects like frame dragging (simply put, massive objects don't just "deform" the canvas of space-time as it is often depicted, they actually drag it along when they move).
Of course, nothing of this has any impact on Ars Magica.
However, whether the Sun or the Earth is at the center of the universe is philosophically and cosmologically important. "As above, so below" and all that stuff.
Without the Earth at the center of the universe, I think Astrology would lose its power. And we do know for a fact that it does work - witness the sympathetic bonuses from horoscopes (not to mention the stuff in Art & Academe or The Mysteries).
Theoretically speaking, it should be possible to determine an absolute frame of reference with respect to the whole of the universe based on the red-shifting of the cosmic background radiation. I'm pretty sure that, in such a frame, you would see the Earth, the Sun and the entire galaxy just fly by.
As to whether the universe has a geometric center... who knows. We'd first have to be sure of its actual topology (including the number of dimensions), which is already a lot of fun considering we can't even see the whole of it.
M.A. philosophy student here, so I am looking at this from a different perspective.
Yes. But we know, on theological grounds, that Earth is not moving.
But this assumes that the Earth moves - which is an assumption that one can reject. There are, I maintain, no empirical facts to contradict this assumption.
This assumption can make the math more difficult, but unless I am badly mistaken, it does not make the math impossible.
Granted, it would be silly to use the difficult math - but doing so would not go contrary to any empirical observations.
No, no. They stay in place. The rest of the universe moves past them, and bits of space-time get held back!
Well, the setting predates positivism, Kantian phenomenology, and whatnot. So trying to explain that the statement that the Earth does not revolve around the sun is not an empirical statement would just get you blank looks - even from people with a high Philosophiae score.
I thought the latest word was that the red-shifting appears the same from any perspective.
But in any case, there may be a point in the universe such, that treating it as the centre makes math easier. But I am not sure what would even be meant by a statement that it is "really" in the centre - above and beyond "it makes the math easier".
The movement of the Earth does have some very measurable effects (e.g. Coriolis forces) which need to be accounted for somehow. It's not just a question of using more complex math, but of justifying the existence of those forces. There's even a term in there for the Earth's revolution around the Sun, but it's usually negligible.
There arevariations in the CMBR, which can have other origins than the proper motion of the observer. But I'm no cosmologist (I just worked with some in the past), so I am not really competent to go into detail.
But yeah, the relative uniformity of the background radiation does certainly put an upper bound on the velocity of the observer...
Although there could be a large-scale cosmic phenomenon that just happen to exactly counterbalance that red-shifting -- we don't really have any way of disproving its existence (in the very same way that you say we can't reject the model of an unmoving Earth).
Actually, Relativity says that you don't have to find such a point, all inertial (i.e. non-accelerating) frames of reference are equivalent. Acceleration breaks the symmetry.
A physics graduate myself, working on my PhD. BA in philosophy too, BTW. But not in related fields, so that doesn't mean squat. At any rate, IIRC...
The current wisdom is definitely that there is no center to the universe: the galaxies are moving apart, not moving from a center; the background cosmic radiation will look about the same from every viewpoint in the universe, and so on. While conjecturing that this is wrong is philosophically possible, it isn't really founded on anything.
The point Gustaf raises is about the relation between reality and our best physical descriptions thereof. The common view is Realism, i.e. that the descriptions are very close to what reality is, and specifically referring to the simple and mathematically beautiful descriptions. In this interpretation, it is enough that general relativity makes the description that earth doesn't move more complex and mathematically ugly and uncomfortable, this implies that this isn't a correct description (and likewise we deduce heliocentrism, no center for the universe, and so on).
This is a philosophical, not scientific, position. It is entirely true that there is no empirical way to examine what is the "truth". But then one has to consider how to seperate a description of something from the thing-itself. I believe that there is ultimately no difference, that we can only speak of things to the extent that they follow descriptions. This means that the question of what is "real" is ultimately meaningless; all that is true is the relations between observations and so on, not any underlying mental model we use to describe them. Physics cannot say whether the earth is "really" circling the sun since "really" has no consequences, it is an empty term.
So my position is that to the extent that anything can be said to be real, the earth circles the sun. To the extent that it can't, it can't - so saying that it doesn't circle the sun is just as meaningless as saying it does, and there is no point in saying "whether the Sun revolves around the Earth or vice versa" in this sense, it is meanignless.
No need to do that at all. The Earth stays still. The rest of the universe revolves around it, and it is the movement of the universe that causes the Coriolis forces.
Yes, I am being silly, but not in any way that contradicts anything that we know scientifically.
Well, some of the more avant-garde thinkers should be able to understand Kantian objections to making the leap from dogmatic reasoning to conclusions about reality (as much as anyone understands Kant anyway). But a real 21st century philosopher transported to AM's Mythic Europe would have to do quite a bit of work to get this across.
Object A is accelerating in relation to object B. How can you know which one is really accelerating?
I think a good point to make canonically in 1220, is yes, the church believed that the earth was spherical, BUT: They believed the earth was still whilst everything else moved around it.
And, canonically in Ars Magica, they are correct on both points.
Philosophically, you can't prove that we're not all in the Matrix. (Philosophy Ph.D. here.) Mythic Europe is a fictional construct in an roleplaying game, so we do know what the reality is there, because in the absence of a causal link reference can only be determined by the words we use, so anything that does not match up to the world as described in canon is not Mythic Europe. This does mean that classical logic is invalid in the Mythic Europe, but then there are reasons to believe that it is invalid in the real world as well, so maybe that's not a big difference.
Voted #4.
Probably noone actually believed in a flat earth (except in a philosophical way, in the same way you might claim that wherever you stand is the center of the world), because as Mr Ferguson said, that is a modern myth, so that obviously rules out #1 completely.
Meanwhile, geo vs helio-centric was an actual issue of debate again and again, so what people believed may be very nonmonolithic, so i chose the most realistic even if it perhaps wasnt the single most common belief.
Might be added that the church was indeed actually a common sponsor for differing views. It seems to have been fine as long as the discussions were between the "pious"...
