Spacetime is not conceptual, not under any model in physics. You'd have to be seriously in denial to think models saying space is curved and correctly predict gravitational lensing and predicts that simulateneity is relative to reference frames is also saying that thing is not part of the world — MindForged

Space-time is part of the model in physics. What is modeled is the way things behave, the way events occur. There's nothing about the model which says that space-time is something real. In fact, to describe space as curved, is to separate space from time, which is not an aspect of the model. So saying "space is curved" is just speaking metaphorically.

That's because "space-time" is purely conceptual. — Metaphysician Undercover

No, space-time is real--it is as it is regardless of what any individual mind or finite group of minds thinks about it.

What is modeled is the way things behave, the way events occur. There's nothing about the model which says that space-time is something real. — Metaphysician Undercover

On the contrary, space-time is the continuous medium (reality) within which discrete things react and discrete events occur (existence).

Spacetime is literally part of the relevant models in physics. Spacetime has it's own behavior which is correctly predicted by current models, namely how it is deformed by massive objects. And I didn't separate space and time. Space is warped as is time, that's really the entire point of Relativity.

No, space-time is real--it is as it is regardless of what any individual mind or finite group of minds thinks about it. — aletheist

That's your opinion. Got any support for that opinion?

On the contrary, space-time is the continuous medium (reality) within which discrete things react and discrete events occur (existence). — aletheist

Where does this idea of a continuous medium come from? Things themselves are the medium of separation between you and I. The medium consists only of discrete things. The continuum is purely conceptual, it's our tool for measuring the discrete things which form the medium.

Spacetime is literally part of the relevant models in physics. — MindForged

Right, it's part of the model, not what is modeled, that was my point. It's theoretical like a perfect circle is theoretical. So we could take a model of a perfect circle, and map real things against it like the orbits of the planets, and see how they vary from the perfect circle. The circle is conceptual, the orbits are real

Spacetime has it's own behavior which is correctly predicted by current models, namely how it is deformed by massive objects. — MindForged

Actually, the model is deficient in its capacity to account for things like gravity and acceleration, so principles are added to allow for the model to be flexible. This gives the appearance that an aspect of the model, space-time is fluid, behaving. In reality the model just changes itself in an attempt to account for the things which it can't properly model. So if you happen to believe that space-time is a real entity, you'll believe that it changes according to those principles which have been added to allow for flexibility of the model.

Take my analogy of the circle for example. Suppose that when it was found out that the orbits of the planets were not real circles, we adjusted the concept of "circle" such that each planet would have a circle for its orbit, and we just dropped the idea of a perfect circle. Then we could claim that a circle is a real thing. That's what you're doing with space-time. The concept has been adjusted to allow for things like gravity, dark matter, dark energy, spatial expansion, etc., and instead of recognizing that this indicates that reality is other than the concept, you claim that this is an indication that the concept is of something real.

↪prothero That's not true. For example, in QM the position and momentum of particles are continuous. Spacetime is also taken to be continuous, time is always taken to be a continuous parameter everywhere in physics. For all the effort out into making space or time discrete, such theories always turn out to be inconsistent somewhere. All (or nearly so) quantum mechanical theories treat spacetime as a continuous parameter, you'd have to go to something much more speculstive like loop quantum gravity to get a discrete structure. — MindForged

The issue is more contentious than that as perusing the physics stack exchange on the subject would show.
https://physics.stackexchange.com/questions/33273/is-spacetime-discrete-or-continuous

That's your opinion. Got any support for that opinion? — Metaphysician Undercover

Can you (or anyone else) establish or change the properties of space-time just by thinking differently about them? Or is space-time something that we must investigate in order to ascertain what its properties are, regardless of what we think about it?

Things themselves are the medium of separation between you and I. — Metaphysician Undercover

Sorry, that is not what it means to be a medium.

The continuum is purely conceptual, it's our tool for measuring the discrete things which form the medium. — Metaphysician Undercover

That's your opinion. Got any support for that opinion?

I'm not really sure what you're pointing at. All the top answers say more or less what I do. It's always taken to be continuous and positing a discrete structure to these things would require adopting a lot of speculative ideas and even ditching assumptions like Lorentz Invariance which by all accounts appears to hold. Not saying it's indisputable but it's so heavily favoring a continuous view that it's way more reasonable to hold that view currently.

Can you (or anyone else) establish or change the properties of space-time just by thinking differently about them? — aletheist

Yes, it's an evolving concept. It came into existence and changed when necessary. Einstein realized the concept of special relativity by thinking differently about space and time. And he realized general relativity by thinking differently about special relativity and gravity.

Sorry, that is not what it means to be a medium. — aletheist

A medium is what exists in the middle, between two places. What exists between you and I, as the medium, is discrete things.

What did you have in mind as a "medium"?

That's your opinion. Got any support for that opinion? — aletheist

Empirical evidence demonstrates to us that all which exists in the world is discrete things. These are the things we sense. We conceive of continuities and continuums, but we never ever encounter such in the empirical world. So the evidence indicates that continuities and continuums are conceptual whereas the physical world consists of discrete things.

Yes, it's an evolving concept. — Metaphysician Undercover

Of course it is a concept, but the issue is whether it is "purely conceptual," as you claim. Why did it have to evolve? Because our understanding changed. Einstein had to think differently in order to resolve observed anomalies that were inconsistent with the thinking of his predecessors. Space-time always was and always will be as it is, regardless of how we think about it; our ultimate goal in studying it is to think about it correctly.

What did you have in mind as a "medium"? — Metaphysician Undercover

A medium cannot consist of discrete things or discrete events, because it is the environment in which those things react and events occur.

Empirical evidence demonstrates to us that all which exists in the world is discrete things. — Metaphysician Undercover

I agree--but continuous space-time is the real environment in which those discrete things exist.

We conceive of continuities and continuums, but we never ever encounter such in the empirical world. So the evidence indicates that continuities and continuums are conceptual whereas the physical world consists of discrete things. — Metaphysician Undercover

What is the warrant for holding that whatever does not exist is necessarily conceptual, rather than real but in a different mode of being? If the discrete things and events that we can and do observe behave in ways that are consistent with continuity, why would we rule out its reality?

Whats logical about ∞ + 1 = ∞ (implies 1 = 0)? — Devans99

But isn't this the mistaken belief that infinity is like other numbers, which it isn't.

If that's the way you approach the problem then zero is also nonsense because we can do 4÷2 but not 4÷0.

When we're faced with the situation 4÷0 we don't say 0 is nonsense or illogical. Rather we tell ourselves that 0 is a ''special'' number that needs, well, ''special'' treatment. We then say 4÷0 is undefined.

Similarly, when we see ∞ + 1 = ∞, it doesn't mean 0=1. Infinity is a special number and normal arithmetic doesn't apply to it.

So in that sense, time is as real as space.
11h — Devans99

I'm still not convinced. There was a theory once called the aether theory, the aether being a medium in which light travels. Given a region of space, say that in a 3cm × 3cm × 3cm box, we could ''measure'' the volume of aether as 27 cubic cm.

Only after Michelson-Morley did their experiment the aether theory was cast into the wastebasket. See? We can ''messure'' things that don't exist.

Could time be like that? Measurable but not real.

A medium cannot consist of discrete things or discrete events, because it is the environment in which those things react and events occur. — aletheist

OK, let's assume that a "medium" is the environment that things exist in. Where do you get the idea that this environment does not consist of discrete things? It seems quite evident that all there is around discrete things is other discrete things. That's what "react" means, one discrete thing is interacting with another. And discrete things overlap each other in their spatial existence, one molecule overlaps another for example, and they interact in this way. There is no need to assume that there is a medium between, or around the discrete things, that's just imaginary, conceptual.

I agree--but continuous space-time is the real environment in which those discrete things exist. — aletheist

But this is false. Relativity theory depends on the assumption that there is no such medium in which things exist. If there was such a medium, it would exist as an absolute, against which all the motions of things could be mapped, in an absolute way. But this contradicts the very premise of relativity, that there is no such absolute, that all motions are relative. So it is clearly impossible that space-time is "the real environment", or "medium", within which discrete things exist, because that assumption would blatantly contradict the premise upon which the concept of "space-time" is constructed.

If the discrete things and events that we can and do observe behave in ways that are consistent with continuity, why would we rule out its reality? — aletheist

They do not though, that is the point. No discrete things, or events, behave in a way which is consistent with continuity, that's a big problem. We map those things with a conceptual structure which assumes continuity. But the models, which allow for infinity, as a feature of continuity, are unable to account for the beginnings and endings of discrete existence. That's a fundamental problem.

When we're faced with the situation 4÷0 we don't say 0 is nonsense or illogical. Rather we tell ourselves that 0 is a ''special'' number that needs, well, ''special'' treatment. We then say 4÷0 is undefined.

Similarly, when we see ∞ + 1 = ∞, it doesn't mean 0=1. Infinity is a special number and normal arithmetic doesn't apply to it. — TheMadFool

4÷0 does not make sense. How can you split 4 loafs into 0 parts? So we have to exclude it from arithmetic for logical reasons. Apart from that, zero behaves fine under the arithmetic operators. Zero has a small quirk but infinity not working with any arithmetic operators is in a completely different league - there is no valid logical reason to exclude infinity from arithmetic and it gives nonsense results with all of them. All other 'numbers' in maths work with the arithmetic operators or analogies of them. Infinity is unlike any other number so we can deduce it is not a number.

If you look at how infinity defined: the cardinality of the set of natural numbers, it must be a positive integer. But there is no integer X wit the property is is greater than all other integers because X+1>X.

Could time be like that? Measurable but not real. — TheMadFool

Space seems real though; its has vacuum/dark energy associated with it and fields so I'd argue they were measuring something real.

If we take a spacial dimension way, maybe we can see what it would be like without time: A 3D cube would become a 2D square. A square is a 2D object with no depth so it does not exist in 3D space (depth=0 so no volume so does not exist).

Imagine then a 3D+time object being changed to 3D-only object by taking time away. A hypercube becomes a cube. By analogy it would cease to exist in 3D+time as it has length zero in time. The object would exist for zero seconds thus not exist in our reality.

So I think time is required for things to exist. We are not living in a pure 3D world, it is a 3D world plus something that enables motion (time).

Could time be like that? Measurable but not real. — TheMadFool

Time is like that. Clock-like objects exist, and we can measure the passing of time using them, but time itself is not an observable - there is no time operator in quantum mechanics. Time may not be real, and may be no more than a correlation phenomenon. There are certainly ideas that future quantum theories will not contain c-number parameters on which observables depend.

In some quantum gravity models, time is absent, notably in the Wheeler-DeWitt model. If such models are on the right track, the arguments for discrete and continuous time seems moot.

It seems quite evident that all there is around discrete things is other discrete things. — Metaphysician Undercover

It seems quite evident to me that there must be a real context within which discrete things exist and react. For example, we say that they have extension in space-time.

If there was such a medium, it would exist as an absolute, against which all the motions of things could be mapped, in an absolute way. — Metaphysician Undercover

First, I am arguing for the reality of space-time, not its existence; as I have stated repeatedly, these terms are not synonymous. Second, there is no necessity for something real to be absolute--the whole point of relativity is that space-time is really relative; as I have also stated repeatedly, continuous motion through space-time is a more fundamental reality than discrete positions in space or discrete moments in time.

No discrete things, or events, behave in a way which is consistent with continuity, that's a big problem. — Metaphysician Undercover

All discrete things and events behave in a way which is consistent with the continuity of space-time. Since you deny this, further discussion would likely be a waste of time.

:ok: :up: :smile:

It seems quite evident to me that there must be a real context within which discrete things exist and react. For example, we say that they have extension in space-time. — aletheist

The "context" is our own measurement of them. We measure their existence, and say that they have "extension" but extension is just how they are represented in the model which provides the basis for measurement. How could they have a measurement without being measured? What is measured is the thing itself, and so it is said to have "extension" as extension is assigned to it through measurement.

First, I am arguing for the reality of space-time, not its existence; as I have stated repeatedly, these terms are not synonymous. Second, there is no necessity for something real to be absolute--the whole point of relativity is that space-time is really relative; as I have also stated repeatedly, continuous motion through space-time is a more fundamental reality than discrete positions in space or discrete moments in time. — aletheist

You said, "continuous space-time is the real environment in which those discrete things exist." I simply pointed out that this is contradictory because "space-time" is a concept that is derived from relativity theory, which has a premise that denies the possibility that discrete thing exist in such a medium.

Therefore, if you want to assign "real" or "reality" to space-time, you need to describe this reality in a way other than as the medium or environment, within which discrete things exist. I suggest we describe "space-time" as real, in the sense of being conceptual, so we provide the necessary separation between the things measured and the means of measurement. This way we avoid the contradiction involved in saying that it is the real environment, or medium in which discrete things exist. Discrete things do not exist in any medium. There is nothing to warrant that assumption.

All discrete things and events behave in a way which is consistent with the continuity of space-time. — aletheist

That's clearly false, and disproven by quantum mechanics. Fundamental particles do not behave in a way consistent with the continuity of space-time.

What is measured is the thing itself, and so it is said to have "extension" as extension is assigned to it through measurement. — Metaphysician Undercover

I see it the other way around--measurement is arbitrary; we impose it by comparing something to a discrete unit, but the underlying reality itself is continuous.

... relativity theory, which has a premise that denies the possibility that discrete thing exist in such a medium. — Metaphysician Undercover

I am not aware of any such premise. Relativity theory is the basis for the current scientific understanding of the space-time continuum.

Discrete things do not exist in any medium. There is nothing to warrant that assumption. — Metaphysician Undercover

There is nothing to warrant the assumption that discrete things can exist and interact without a continuous medium within which to do so.

Fundamental particles do not behave in a way consistent with the continuity of space-time. — Metaphysician Undercover

I am not aware of any such evidence. I view the Planck length and Planck time as limitations on observation and measurement, not real discrete units of space-time.

I see it the other way around--measurement is arbitrary; we impose it by comparing something to a discrete unit, but the underlying reality itself is continuous. — aletheist

I think I see what you're saying, but I believe the situation is more complex than you make it out to be. I agree that we measure in discrete units, numbers, and that there is arbitrariness in the measurement.. But I think that the idea that the thing measured is continuous is an assumption that we make which is made to support arbitrary the measurement. It is not based in evidence. The evidence, such as Zeno's paradoxes indicates that the underlying reality is discrete. Nevertheless, if the thing measured is continuous, then the discrete units of measurement may be arbitrary without any negative effect to the validity of the measurement. So we assume continuity of the underlying reality because this validates arbitrary units of measure. However, the assumption of continuity creates problems like Zeno's paradoxes which demonstrate that the underlying reality is likely not continuous. So I conclude that in reality things are discrete, but since our units of measurement are arbitrary, based on the assumption that the underlying reality of things is continuous, our arbitrary units are incommensurable with the underlying real units. Therefore we have problems with some measurements which need to be precise.

I am not aware of any such premise. Relativity theory is the basis for the current scientific understanding of the space-time continuum. — aletheist

Right, but the space-time continuum is understood by physicists as conceptual. It is not understood as a medium within which things exist. This would contradict the fundamental principle of relativity, that things do not exist within such a medium. The "space-time continuum" is the fundamental principles upon which a coordinate system can be constructed, just like "Euclidean space" is. They are each, "space-time continuum", and "Euclidean space", fundamental concepts upon which models are build. We don't say that things exist in the medium of Euclidean space, because we recognize that Euclidean space is completely conceptual. Likewise with "space-time continuum". Physicists don't say that things exist in the medium of the space-time continuum, because they recognize that this is just a conceptual structure.

There is nothing to warrant the assumption that discrete things can exist and interact without a continuous medium within which to do so. — aletheist

I already explained this to you. Discrete things overlap in their existence, just like molecules as discrete things, overlap one another. There is no place in the physical realm for a continuous medium, or a need to assume one. The only reason for assuming a continuous medium is to justify the easy choice of arbitrary units of measurement. If we recognized that the underlying reality consists of discrete units rather than assuming a continuity, then we could not justify the use of arbitrary units of measurement because our units would have to be commensurate with the real units. Instead, we take the easy way, assume continuity and make arbitrary units of measurement. And this produces measurement problems.

I am not aware of any such evidence. — aletheist

Are you unaware of the uncertainty principle, the measurement problem, and quantum entanglement? These are evidence that fundamental particles do not behave in a way which is consistent with the continuity of space-time.

However, the assumption of continuity creates problems like Zeno's paradoxes which demonstrate that the underlying reality is likely not continuous. — Metaphysician Undercover

Huh? The assumption of discreteness is what creates problems like Zeno's paradoxes. As I have said before, recognizing that continuous motion through space-time is a more fundamental reality than discrete positions in space or discrete moments in time dissolves Zeno's paradoxes.

Right, but the space-time continuum is understood by physicists as conceptual. — Metaphysician Undercover

I suspect that would be news to many physicists.

There is no place in the physical realm for a continuous medium, or a need to assume one. — Metaphysician Undercover

Who said anything about the physical realm? This is conflating reality and existence again.

Are you unaware of the uncertainty principle, the measurement problem, and quantum entanglement? — Metaphysician Undercover

I am not aware of any reason to interpret them as inconsistent with the continuity of space-time.

Heidegger critiqued the notion of time that modern physics inherited from the Greeks.
" Einstein's theory of relativity established the opinion
that traditional philosophical doctrine concerning time has been shaken
to the core through the theory of physics. However, this widely held
opinion is fundamentally wrong. The theory of relativity in physics does
not deal with what time is but deals only with how time, in the sense of
a now-sequence, can be measured. [It asks] whether there is an absolute
measurement of time, or whether all measurement is necessarily relative,
that is, conditioned.* The question of the theory of relativity could not
be discussed at all unless the supposition of time as the succession of
a sequence of nows were presupposed beforehand. If the doctrine of
time, held since Aristotle, were to become untenable, then the very
possibility of physics would be ruled out. [The fact that] physics, with
its horizon of measuring time, deals not only with irreversible events,
but also with reversible ones and that the direction of time is reversible
attests specifically to the fact that in physics time is nothing else than the
succession of a sequence of nows. "

Heidegger's point is that whether one posits a continuum or discrete units, time as a counting of nows misses the irreversible, creative basis of temporaity. From biology we know that you cannot un-fry and egg, but in physics temporal phenomena are presumed to work just as well in reverse as forward.

Huh? The assumption of discreteness is what creates problems like Zeno's paradoxes. As I have said before, recognizing that continuous motion through space-time is a more fundamental reality than discrete positions in space or discrete moments in time dissolves Zeno's paradoxes. — aletheist

The discreteness in Zeno's paradoxes is not an assumption, it's a fact of the measurement system, the numbers represent discrete units. The moving items must cover the discrete units of distance, in the discrete units of time, provided by the measurement system. The measurement system gives us discrete units. However, continuity in the actual distance and time is assumed under the claim of infinite divisibility. The paradoxes are created by that assumption of continuity.

I am not aware of any reason to interpret them as inconsistent with the continuity of space-time. — aletheist

Are you telling me that the observed behaviour of quantum particles which cannot be explained by the laws of physics, does not indicate to you that the behaviour of these discrete units is inconsistent with the continuity of space-time?

The theory of relativity in physics does
not deal with what time is but deals only with how time, in the sense of
a now-sequence, can be measured. — Joshs

Heidegger was quite advanced in his understanding of time. Do you see the fact revealed in this quote? How the physicists tend to deal with this problem, Einstein included, is to deny that time is anything other than a tool for measuring. By denying that time is even something which is measured, the question of "what time is", is left as inapplicable.

4÷0 does not make sense. How can you split 4 loafs into 0 parts? — Devans99

But 4-4=0. 0 isn't nonsense. Likewise the infinity of natural numbers isn't nonsense.

Infinity + 1 = Infinity but just as you're not allowed to divide by zero, you're not allowed to do ''normal'' arithmetic with infinity.

Do you know that our forefathers didn't know how to count beyond 2. There was 1, 2, and many (meaning an indefinite amount or infinity). I hear that some Amazonian and African tribes still count so.

In a group there were either 1 or 2 or many (infinite) people.

In their case 2+1= 3 was infinity.

So, 3+1=4 for us at present but for our ancestors it was infinity/many(3)+1=infinity/many(4)

Do you suppose we're in that stage, like our ancestors, as regards the notion of infinity?

In this context, Georg Cantor made a huge contribution by showing, through the simple logic of 1 to 1 correspondence, that some infinities were bigger than others. In fact he showed there are infinite infinities.

Cantor's achievement could be likened to us, at present, discovering that 2+1= 3 and 3+1=4 which to our forefathers was 2+1=infinity or infinity+1=infinity.

As for time, I'm still in doubt whether it's real or not.

How do we invent a theory that doesn't inclide time?

Can you explain? Thanks.

Right, it's part of the model, not what is modeled, that was my point. It's theoretical like a perfect circle is theoretical. So we could take a model of a perfect circle, and map real things against it like the orbits of the planets, and see how they vary from the perfect circle. The circle is conceptual, the orbits are real — Metaphysician Undercover

Spacetime is modelled. Like what are you talking about? When I say it's part of the model I mean we have a set of propositions in a theory based on observable evidence which is closed under logical consequence. It's not just this background thing that is immaterial to the meat and potatoes, Spacetime is a real thing.

Actually, the model is deficient in its capacity to account for things like gravity and acceleration, so principles are added to allow for the model to be flexible. This gives the appearance that an aspect of the model, space-time is fluid, behaving. In reality the model just changes itself in an attempt to account for the things which it can't properly model. So if you happen to believe that space-time is a real entity, you'll believe that it changes according to those principles which have been added to allow for flexibility of the model. — Metaphysician Undercover

What? General relativity gives us an incredibly accurate understanding of gravity and acceleration. Spacetime is deformed by massive objects, the model isn't changing. That's a prediction of the model and one which is true. We have to account for the deformation of space by the planet Earth in order for our satellites to orbit properly. We literally observe this warping in distance pictures of galaxies because dark matter causes gravitational lensing, the distortion of Spacetime. Distortion is behavior, spacetime isn't somehow unaffected in the way you are insisting, no argument is given, nor evidence presented. Like come on, you're not giving anything serious to overturn the overwhelmingly minority position you hold as compared to physicists on the issue.

Absolutely. Heidegger also understood how the way physicists accept uncritically their results, without recognizing the way their truths are conditioned by their presuppositions, leads to statements like the following from MindForged: "General relativity gives us an incredibly accurate understanding of gravity and acceleration."

The issue of the arrow of time is well known in physics. The idea that it's not something that's ever been critically looked at or thought about by physicists is absurd. That sort of statement can only be made in ignorance. It's not a novel insight to say truths are conditioned by presuppositions. That's a trivial observation that holds everywhere, an actual point would be to show those presuppositions are false or questionable. I'll let you be the one to argue that physics has the wrong view about time and never critically examines it's assumptions.

Its not a question of having a right or wrong view, but that all views , as perspectives, dictate the limits of what can be seen, what counts as evidence. I follow Thomas Kuhn rather than karl Popper in this regard. Truth is relative to perspective and the way in which scientific perspective shifts over cultural history cannot itself be subsumed with an overarching theory of truth as correspondence with the 'way things really are'. This does not mean that we cant talk about development of science in a pragmatic sense in terms of its usefulness relative to our evolving needs, But if you want to think of accuracy as our representing of some supposed independent objective outside you will run into the problem that truth is a useful way of interacting with a world, but in interacting with it, we alter that world, which then alters our perspective. So empirical accuracy is always with respect to a scientific perspective within which that empirical description has meaning . The shift to a new paradigm brings with it a qualitatively different account within which empirical accuracy can function.
Whats most powerful about scientific development isnt its accuracy so much as its capacity, along with the development of philosophy, to enact qualitative shifts in its perspective over time.
Lee Smolen is one of those natural scientists (Ilya Prigogine is another) who would argue that a revolution of philosophical worldview within physics is necessary to keep pace with where philosophy has already gone after Darwin . with respect to temporality. This shift in thinking would not necessitate the invalidation of any of the prior empirical results , but rather a re-envisioning of the significance of those results within a metatheoretical framework that would open up new horizons of discovery.

How do we invent a theory that doesn't inclide time?

Can you explain? Thanks. — TheMadFool

No, I can't explain how models like the Wheeler-DeWitt equation are come by, but I can point our a rather beautiful feature of such models.

In the Wheeler-DeWitt model (for example) time is absent, because the universe as a whole is at rest. This is because the universal wavefunction is in an eigenstate of its Hamiltonian. This in turn is necessitated because otherwise physical quantities would depend on the unphysical c-number parameter t.

Now, because the universe is in an eigenstate of its hamiltonian, it is NOT in an eigenstate of the position of the hands on the face of a clock, or the state of any clock-like object. Rather it is in a superposition of those states. Time is thus a correlation phenomenon.

Now for the bad news. It seems to me, that this model is irresistibly yields a Many-Worlds interpretation of Reality, in which different times are just special cases of different worlds, that are connected by the laws of physics.

Spacetime is a real thing. — MindForged

Right, spacetime a real concept, just like unicorn is. The fact that it's extremely useful separates it from the concept of a unicorn, which is not so useful. However, this just places it more like the concept of Santa Clause, or the perfect circle, a very useful concept.

General relativity gives us an incredibly accurate understanding of gravity and acceleration. — MindForged

No it doesn't it just gives us the means for modelling the effects of gravity. General relativity gives us no understanding of gravity itself, none at all. If it did, it could point us to the graviton.

Like come on, you're not giving anything serious to overturn the overwhelmingly minority position you hold as compared to physicists on the issue. — MindForged

I've talked to many physicists, and your claims, that space-time is more than just a conceptual tool, is just not consistent with what these physicists tell me. You're just taking an extremely speculative metaphysical proposition, and claiming that physicists believe this proposition. Maybe some do.


Acceleration is something which physics has never been able to properly model. The basic problem is that a thing at rest, must go from zero velocity to a positive velocity at some particular time, so its acceleration would be infinite at that particular time. Relativity, in a way, sidesteps this problem by denying absolute rest, and different frames of reference can be employed. However, this just creates a convoluted relationship between potential energy and kinetic energy, and so, the fact that acceleration is not actually being properly modeled is hidden under this complexity.

However, continuity in the actual distance and time is assumed under the claim of infinite divisibility. The paradoxes are created by that assumption of continuity. — Metaphysician Undercover

We have been over all of this before. Infinite divisibility is a red herring. Continuous motion through space-time is the fundamental reality. An interval of space does not consist of infinitely many discrete positions, and an interval of time does not consist of infinitely many discrete instants.

Are you telling me that the observed behaviour of quantum particles which cannot be explained by the laws of physics, does not indicate to you that the behaviour of these discrete units is inconsistent with the continuity of space-time? — Metaphysician Undercover

I am telling you that I am not aware of any reason to interpret them as inconsistent with the continuity of space-time.