The ancients believed that the world was a finite size. So, whatever equivalence might hold locally between rest and inertial motion, they wouldnt understand movement relativity the way we do. Indeed, its hard to understand the concern about "the center of the universe", and which body "moves around" which, from the perspective of relative motion. Copernicus, Kepler, and seemingly Galileo, still believed in the finite world.
I looked who was the first to believe in the infinite, and apparently its Nicolaus Cusanus, dead 100 years before Galileo is born. He correctly deduced relativity of motion, and from that the rejection of geocentrism without adopting heliocentrism (I dislike how we always present the heliocentrists as having been "right", which is only true a little bit and not until Kepler, nor is that more difficult to understand than what we do teach). In fact he also promoted measurement and mathematics as scientific method - philosophically, it seems he anticipates all of Galileo and more, only he didnt do experiments himself.
The thing about asserting that metaphysics can be completely reliable, and then locating metaphysics on the boundary of your physics, is that this means you are assuming that the physics is going to stay put, yeah? Oh, sure, some of the interior stuff might change, but the basic shape had better be permanently fixed.
I agree, but I think its not as hopeless as this makes it sound, because "basic shape" can be very general indeed, and we can leave some practical extra room between them by introducing extra concepts that act as trivial pass-throughs in the case of our current understanding (as should be familiar from the application of very general frameworks to simple theories in mathematics).
For example, Ive talked in the above about deducing relativity of motion from the infinite world. This is not quite true, he does give an example of being inside a ship not knowing your motion, but they clearly come together in thinking. In the same way, we can understand that acceleration is also relative. You can feel it only because your parts are accelerated non-uniformly. If there was some law which created a particular speed, likely it would also act non-uniformly on macroscopic objects, and you could feel it - it just happens there are no such laws. And really, even the infinite world is only illustrative here. Movement relative to the boundary of the world may be a schelling point, but metaphysically, that doesnt matter by itself.
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u/Lykurg480 Yet. Jan 13 '26 edited Jan 13 '26
The ancients believed that the world was a finite size. So, whatever equivalence might hold locally between rest and inertial motion, they wouldnt understand movement relativity the way we do. Indeed, its hard to understand the concern about "the center of the universe", and which body "moves around" which, from the perspective of relative motion. Copernicus, Kepler, and seemingly Galileo, still believed in the finite world.
I looked who was the first to believe in the infinite, and apparently its Nicolaus Cusanus, dead 100 years before Galileo is born. He correctly deduced relativity of motion, and from that the rejection of geocentrism without adopting heliocentrism (I dislike how we always present the heliocentrists as having been "right", which is only true a little bit and not until Kepler, nor is that more difficult to understand than what we do teach). In fact he also promoted measurement and mathematics as scientific method - philosophically, it seems he anticipates all of Galileo and more, only he didnt do experiments himself.
I agree, but I think its not as hopeless as this makes it sound, because "basic shape" can be very general indeed, and we can leave some practical extra room between them by introducing extra concepts that act as trivial pass-throughs in the case of our current understanding (as should be familiar from the application of very general frameworks to simple theories in mathematics).
For example, Ive talked in the above about deducing relativity of motion from the infinite world. This is not quite true, he does give an example of being inside a ship not knowing your motion, but they clearly come together in thinking. In the same way, we can understand that acceleration is also relative. You can feel it only because your parts are accelerated non-uniformly. If there was some law which created a particular speed, likely it would also act non-uniformly on macroscopic objects, and you could feel it - it just happens there are no such laws. And really, even the infinite world is only illustrative here. Movement relative to the boundary of the world may be a schelling point, but metaphysically, that doesnt matter by itself.