It is quite clear that, in Eternalism, the 3D part existing at t1 is not the same as the 3D part existing at t2. You wouldn't say that the 3D part at t1 moves to t2; clearly not: a different part exists at t2. — Luke
You may wish to argue that it is the same object in Eternalism: the 4D object. But this would imply that it is the 4D object which moves or changes temporal location, and that makes little sense. — Luke
It is quite clear that, in Eternalism, the 3D part existing at t1 is not the same as the 3D part existing at t2. You wouldn't say that the 3D part at t1 moves to t2; clearly not: a different part exists at t2. — Luke
Yes, iirc I did ask for clarity on "3D part", I wasn't sure if you meant the body or its spatial coordinates. Continuity is what makes it the same object. Although, the ship Theseus and all that. — Kenosha Kid
To compare Presentism and Eternalism we need to talk about 3D objects, which is what motion typically deals with anyway. Eternalism doesn't have 3D objects so we need to use 3D parts of a 4D object instead. — Luke
Yes, iirc I did ask for clarity on "3D part", I wasn't sure if you meant the body or its spatial coordinates. Continuity is what makes it the same object. Although, the ship Theseus and all that. — Kenosha Kid
You may wish to argue that it is the same object in Eternalism: the 4D object. But this would imply that it is the 4D object which moves or changes temporal location, and that makes little sense. — Luke
The mountain at the summit is the same mountain as the one at the foot. What is it then that changes spatial position? — Kenosha Kid
It's not my definition, blame Galileo! — Kenosha Kid
An effect of the motion of the teacup is that it is now on the floor. — Kenosha Kid
my everyday experience of motion: the thing is not where it once was. — Kenosha Kid
If that's your level of argumentation, we cannot trust that each other are trying their best to explain what seems true to them. Further discussion would be pointless. I'm not having a go; you've described exactly how I feel about everything you have said. I just would have persevered and tried to reconcile our different experiences of motion, or perhaps got a consensus on another thread. — Kenosha Kid
What is it then that changes spatial position? — Kenosha Kid
What's required is continuity: the geometry of the mountain. — Kenosha Kid
Same goes for 4D objects. The Moon at some future event is the same as the Moon at some past event: both events are points on the Moon. What makes it the same Moon is continuity. — Kenosha Kid
What is it then that changes spatial position?
— Kenosha Kid
In Eternalism? Nothing. That's what I'm arguing. Nothing moves; nothing changes. — Luke
Forget eternalism. Just a mountain at a given moment in time, an aerial photograph of you will. The summit is in one place. The foot is far away from it. It exists in more than one position. — Kenosha Kid
The summit is in one place. The foot is far away from it. It exists in more than one position. By your argument, radius is impossible because what changes spatial position? — Kenosha Kid
Irrelevant. For which object are you measuring the motion? The mountain. So you need to measure the change in its temporal position. This will require that the same mountain (edit: object) is "defined for more than one time". And then see my argument. — Luke
I can calculate the gradient of the mountain at any point by measuring the "change" in altitude with "change" in radius. These are not changes over time, these are merely lengths. Not does that gradient depend on me measuring it. — Kenosha Kid
The same goes in 4D, where I can measure motion as "change" in spatial position with "change" in temporal position: these are lengths. And the motion is there whether I measure it or not. — Kenosha Kid
The gradient of the mountainside is not a change in the spatial position of the mountain, as you implied earlier. The mountain hasn't moved. — Luke
Precisely, and yet it has spatially-dependent altitude (a gradient). — Kenosha Kid
What object has changed its spatial location? Please tell me. — Luke
Nor does that gradient depend on me measuring it. — Kenosha Kid
You do not need to "change" spatial location — Kenosha Kid
Are you trying to "change" the subject? I thought the subject of our disagreement was whether there is motion in Eternalism. I've given my argument for why there isn't. You may need to clarify how this response addresses that argument. — Luke
In short, your counter-argument is equivalent to saying that, at a given moment, a mountain must be flat because there is nothing "changing" position to allow its altitude to vary with position. — Kenosha Kid
I'm not going to argue with you by analogy. There is no long-standing debate about whether altitude of a mountain can change with position. This is about time and motion. — Luke
This seems to be par for the course: every opportunity I've suggested to consider how motion is possible in eternalism, you have given some excuse to look away. It all comes down to dx/dt being well-defined in eternalism as d(altitude)/d(radius) is defined for a mountain at any given time, and that the geometry of a 4D object is not dependent on how we calculate it, just as the geometry of a mountain is not dependent on how we calculate it. — Kenosha Kid
Oh my god. Your argument is little more than motion is possible in Eternalism by definition. The least you could do is address my argument if I'm so obviously wrong. — Luke
Show me where I've used a different definition of motion. — Luke
Your argument is little more than motion is possible in Eternalism by definition. — Luke
Therefore your argument is nothing more than: "motion is impossible in Eternalism by definition". — Kenosha Kid
My argument is based on these definitions. — Luke
I've actually presented an argument. Where's yours? — Luke
Then motion is possible by definition, since the time-dependence of an object's position is retained in the eternalist picture. — Kenosha Kid
Your responses have amounted to circular arguments, contradicting yourself, and refusing to ever consider any point that would resolve the argument when offered — Kenosha Kid
What does "the time-dependence of an object's position" have to do with either of the definitions that we previously agreed to? — Luke
a 4D object's position depends on time — Kenosha Kid
This is an example of taking the time to explain oneself. — Kenosha Kid
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