Comment by nicebyte
2 hours ago
sorry, saying that "it's a matter of taste" whether the earth revolves around the sun is completely ridiculous. making useful predictions is one thing, but actual truth is not a "matter of taste".
2 hours ago
sorry, saying that "it's a matter of taste" whether the earth revolves around the sun is completely ridiculous. making useful predictions is one thing, but actual truth is not a "matter of taste".
They both revolve around their barycenter. So neither one revolving around the other is ground truth. In practice either one can be the right choice (earth at center for video game, sun at center for astronomy predictions).
My point is that the laws of physics work just fine in a wide variety of mathematical framings. It's sensible to pick a framing that keeps the complexity of the equations as low as possible, but you're not incorrect if you pick a frame that puts the moon in the center or any other point. The accuracy of the theory's predictions are completely separate from where it applies labels like "center".
I mean to be completely accurate the Earth doesn't strictly orbit the Sun. Both the Sun and Earth orbit each other around a point at their "combined" center of mass, the barycenter - https://en.wikipedia.org/wiki/Barycenter_(astronomy). This is something you need to take into account for all the planets in the solar system and as a result, the "center" of the whole system is constantly moving. The solar system's barycenter is often not even inside the Sun.
I think that sort of proves the point that the OP was making, which is that you can create a functional model around any arbitrary location and it can be valid (as long as valid means: it can make useful predictions). When you put the center of the Sun at the center of the model, you still need your models to account for the "orbital wobble" happening as a result of the Sun doing a little dance with Jupiter (and all the other masses that orbit it) in the equations for the determining the relative positions of the Sun and Earth.
Using the Sun as the center versus the solar systems barycenter are both somewhat "arbitrary" in that way, and depend on what you're trying to do with the information - how accurate you need it to be, and how complicated you're willing to make the calculations to hit higher accuracies.
If I just add a few more parameters to my model I can make it fit anything!
Sure, it depends on what you're trying to do. Fit an equation or understand it. Yes, you can use a reduced mass to simplify the equations and make it more accurate, which usually isn't necessary when the new center is at less than 1% of the radius of the Sun (note ellipses have 2 foci from Kepler/Newton). Even Jupiter's center of rotation is at the surface of the Sun, and both have eccentricities <1%.
Of course, if you're using epicycles, you're never going to get Einstein's elliptical precession correction to the orbit of Mercury. Simpler, is usually better for models, even when you need greater and greater accuracy, overfitting is the enemy of explanation (to coin a phrase).
All models are wrong, some are useful. - Box
Epicycles weren't untrue, they're just an unnecessarily complex model that can be used to describe what picking a different point of reference can yield as a much simpler model. Not all heliocentric models got everything right just because they picked a simpler reference point for producing a model. Judge a model based on its accuracy, not its point of reference.
I think we disagree pretty fundamentally on what something "being true" means.
It's possible to come up with an "unnecessarily complex model" for why someone accused of a crime did the crime, but that has completely no bearing on whether the defendant is actually guilty. If the defendant is, in fact, innocent, then the prosecution's model is, in fact, untrue - no matter how well it fits the evidence.
> no matter how well it fits the evidence
Are you proposing that an explanation can be true even though there's a different explanation which better fits the evidence?
Or are we talking about cases where both candidate explanations fit the evidence equally, and you have access to some kind of intuition which tells you which of the two are true?
> Epicycles weren't untrue, they're just an unnecessarily complex model that can be used to describe what picking a different point of reference can yield as a much simpler model.
That’s another way of saying it’s untrue.
> Judge a model based on its accuracy, not its point of reference.
Something can be both accurate and wrong, in the manner of a model that pinpoints the cause of death from cancer as admission to a cancer ward.
That's an interesting stance to take. So if you have multiple theories all of which make the same predictions, are you saying that the simplest one is the true one?
Are you sure there will always be just one simplest theory? Or are you using some other criteria to pick it?
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> but actual truth
there is no "actual truth" - there is only what you can measure reliably
https://en.wikipedia.org/wiki/Epistemology
unless you subscribe to an entirely solipsistic worldview, "actual truth" obviously exists regardless of your ability to measure or perceive it.
Is it useful to invoke it though? Once two people claim to know the actual truth, yet they disagree, you're at an impasse. There's no method for resolving which allegedly obvious claim is in fact the truth.
Predictive power on the other hand, gives you a framework to decide which story is more useful.
Brother you're wrong and there's ample scholarship you can consult to correct your misunderstanding. The Wikipedia with sufficient citations is right there. Feel free to educate yourself.
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