So your perspective is more psychological and related to our conscious experiences. Is this a Berkeley or Kantian strategy you are gleaning from in treating spacetime as a fundamental psychological process but nothing more? — substantivalism

I said it is a psychological choice when I decide what components comprise a system or not. The physics of the relationalism has zero to do with this choice.

I get that this philosophical viewpoint is not emprically well-founded and never could be (it would be consistent with any personal experience) but it always felt relatively possible. — substantivalism

I find the acquisition of new information to be a contradiction in the solipsistic idealist view. Say you find a tomb full of Egyptian writing and spend years trying to decipher it. You've memorized every character and could reproduce it at will from memory, yet you cannot read it. After years of study, you finally break the code and learn the language, and suddenly there is information that was always there, but suddenly is meaningful to you. That implies there is something out there that didn't come from you. I cannot dream of a coherent language that I don't yet understand. Something else has to have produced that tomb, which contradicts your experience being more fundamental than the noumena. That contradiction sinks the view in my opinion.

Two quick questions:

1. Does black hole time travel increase or decrease Time ( I can't remember)?
2. Do black holes contribute to Multiverse theories at all? — 3017amen

Time slows (is more dilated) when deep in a gravity well, So clocks on Earth for instance run objectively slower than say GPS clocks (which are very high up and not moving fast). Those GPS clocks are slowed due to their orbital motion, but the gravity effect is greater at that altitude. Clocks on the ISS run slower than the ones on the ground due to minimal gravitational potential difference in low orbit, coupled with significant dilation from the higher orbital velocity. So at an altitude of 1.5 R (R being Earth's radius), the two effects cancel out and orbiting clocks can be synced indefinitely with those on the ground.

Similarly, from the PoV of the distant observer, a clock falling into a black hole freezes on the event horizon. It doesn't just appear to freeze. Coordinate time slows and actually stops there.
From the PoV of the observer falling in, he sails right in without a hitch, and the universe behind him appears to speed up, but not infinitely so. There's definitely a time outside the black hole beyond which is not part of his past light cone, and thus is not observable.

About the multiverse thing, I think there are theories that a black hole in one universe is a white hole from the perspective of the interior spacetime. I think we're possibly supposed to be in such a white hole in some of these theories, except I don't see how we could be expanding then. There's no singularity (big crunch) at the end of time like one would expect from a geometry with an abrupt cessation of time like that.

Thanks for your initial responses.

I've been in discussion about this on physics sites, but they don't care so much there about the metaphysical implications to absolute time interpretations.

As you can see, any event can be located in an inertial frame, but only those events within our past light cone can be detected by us now. Events outside that cone are still in the reference frame but cannot influence us. — Kenosha Kid

You've drawn flat Minkowski spacetime (with arbitrary inertial frame) in which light from any spatial location will reach any other location. That makes it an inappropriate model of the large scale universe where light that is currently say 17 GLY away will never get here, not in 17 billion years or ever.
Earth has an event horizon, and Minkowski spacetime does not. The universe cannot be foliated with such a coordinate system.

Gravitation can't be accurately described by inertial frames but require curvilinear coordinate systems. — Kenosha Kid

You can still foliate reasonable gravitation in 'bent' Minkowski spacetime, but not black holes. So for instance, a device measuring absolute time here on Earth would run apparently faster than one on the surface of Saturn due to the lower gravitational potential here on Earth. The same device on a ship with relativistic absolute speed would similarly appear to run faster (than the clock next to it) than it would if the ship had low peculiar velocity.

I don't get this. Why would they have to reach us? — Mr Bee

There's no requirement for light to reach any location from any other since there are very much cases where that does not occur. My point was that in an inertial frame, light can reach location X from Y given enough time, and thus such a model is not a model of our universe.

The light will never reach us because of cosmic expansion, so the fact that we don't see them doesn't mean they don't exist.

If there is a boundary to an inertial frame, then event outside that boundary do not exist in that frame. An inertial frame does support cosmic expansion, but it does not support acceleration of that expansion. So given no such acceleration, there would be no event horizon and light will eventually get from location X to Y given time. And even locally, an inertial frame cannot foliate the interior of black holes, so it fails twice.

I'm not sure about that. As far as I know, any spacetime that doesn't allow for closed timelike curves is open to being sliced into global hypersurfaces.

There are indeed ways to do it with a single black hole, but you must assume the black hole is at some kind of privileged location. So consider 3 events: A clock is dropped into a black hole. Event A is that clock 1 second (measured on that clock) after passing the event horizon. The black hole is big enough that it survives at least one second. The rock is dropped from a hovering location outside, which shines light down on the dropped clock. At some point the last light is emitted from this location that will catch up to the dropped clock before it hits the singularity. Event B is that hovering location 1 second after that last light goes out.
Event C is at the location of the former black hole after it has evaporated.
Yes, you can come up with various schemes to order these three events, but do any of those schemes order all of spacetime? OK, C occurs after B since it is in the future light cone of B. That's easy. Not so easy with event A.


I'm not suggesting retrocausality anywhere. Event A is not causally connected with either B or C, so no objective ordering scheme is going to produce a contradiction unless B is in A's future but C is in A's past.

I mean no disrespect — substantivalism

None perceived. I agree with your comment that there is a general aversion to solipsism among philosophers, and I was just pointing out that the aversion itself is a poor reason to reject any view. I personally find the view self contradictory, and reject it for that reason.

We see eye to eye on the geocentrism and anthropocentrism of view points as I also find metaphysics which make us highly centered in the grander scheme of things likewise also highly suspect.

Yes, but again, I identify that as a personal bias, and therefore not good grounds for rejection. Who knows, maybe the universe is made for us. That possibility must be considered, but positing such doesn't seem to explain anything better than more plausible views.

It's like a sorites problem of sorts to attempt to specify where you end and the greater worldly environment begins.

Where I end (spatially, not temporally) is an interesting problem. It seems to be a purely abstract thing. The guy in the sci-fi show straps a time travel device to his wrist and it takes him and his clothes and briefcase to some other time, but doesn't take the nearby shrubbery. How does the device know what's you and what's not? It's intuitive to us, but in trying to tell a device how to do it, it turns out it isn't obvious at all.
Where does a mountain stop? Most of them don't sit nicely on an otherwise flat surface that gives an obvious boundary delimiting mountain from the surface on which it rests.
All these things are part of exploration of identity, but not particularly important to relationalism, which cares not so much what one defines as a 'system' or not.

Yeah, solipsism really makes a philosopher run for the hills doesn't it. — substantivalism

Just because it's distasteful doesn't mean it's wrong. But I think there are serious logical problems with the solipsistic view, coupled with a personal bias against any sort of geocentrism, anthropocentrism, or any other view asserting us having a privileged status.

It was just the words being used by you such as 'me' that made me think you were taking a sort of idealist direction for you metaphysics but I was wrong there.

If I want to be formal, I had to find a definition of 'me' that didn't violate the law of identity, and it pretty much makes a hash of the way 'me' is used in everyday language. Language is littered with unstated premises, all of which I question (hence my user name), and most of which I cannot justify.

Under RQM, experiencing something has nothing to do with it being real. There simply needs to be a relation, especially a measurement. So the apple exists relative to the rock iff the rock measures the apple in some way. The rock having conscious experience of the apple has nothing to do with it. That kind of thinking leads to solipsism. Think Wigner interpretation, which many people hold without knowing it, but even Wigner himself abandoned it due to the solipsism thing.

I don't do polls, but I'm a relationist is probably far more ways than the one you describe.

Yes, time has no meaning without regular change to define it. Space has no meaning without at least three locations so that it can be meaningfully expressed that A is closer to B than is C. Without physical objects to anchor those locations, they're just abstract geometry to us. I consider our reality to be 'real' only because it relates directly to me, however I might care to define 'me'.

As for relational interpretations of special relativity, yes, I tend to favor RQM (Rovelli).

I think I read your post wrong, because upon re-reading it, I agree.

OK, then it works the same way that my thermostat turns on the heat in the winter despite the fact that it's warm in mid-May.

I'm very sorry that you seem totally incapable of understanding an alternate point of view. I cannot help you with that. Not asking you to change your beliefs, but you have no argument for or against one side or the other of any philosophical issue if you don't have even a rudimentary understanding of both points of view.

How does that work if your consciousness is not crawling up a worldline? — Luke

The same way my thermostat turns on the heat in the winter despite the fact that it's warm in mid-May. No need for a 'measurment' spotlight to crawl up the thermostat's worldline in order to allow it to function.

All that is left to account for is the motion of one's consciousness crawling upward along the worldline. — Luke

If that's how it works, it is still a form of presentism, with the consciousness (not part of the block) acting as the spotlight and defining a present. Dualism doesn't fit well at all with eternalism under which the entire worldline of a person is conscious. It would be rather absurd to say that the 1997 portion
of me is not conscious of the events of 1997.

Or alternatively we are stages which are located at a single instant and experience only that one instant of time while other counterparts experience the others. You know, cause experiencing every moment has the whole obviously wrong thing going on with us experiencing only one moment. — Mr Bee

Eternalism does not suggest that every state of a person along his worldline experiences every time in the worldline. That would be empirically quite different, wouldn't it?

If B-theorist eternalist are right, and we are beings that only experience one moment in time — ChatteringMonkey

we are only privy to one moment and so experience it as passage of time. — ChatteringMonkey

Ouch. Under eternalism, we beings are worldlines, and experience every moment along that worldline. So iff I define 'me' to be my worldline, then I am present at some event in 1995 and also 2021, and I experience those events and all others. There is none of this 'privy to one moment', which again smacks of a preferred moment.

The eternalist says that every point in time is equally real — ChatteringMonkey

I'd say 'has equal ontological status'. There's a difference to us non-realists.

Hate to butt in, however, these are all unproven theories? — Outlander

They're interpretations actually, despite all the literature referring to them as theories. No, neither interpretation can be falsified since they do not make distinct empirical predictions. All attempts to discredit one or the other proceed along logical grounds, not scientific ones.

If you perhaps fancy and have the time, could you explain in layman's terms. What differentiates eternalism from the moving spotlight theory?

The spotlight defines a present (preferred) moment, which makes it presentism, just like all the other variants described in the OP. Eternalism asserts the lack of a present,and doesn't seem to have so many variants.

Both have past, present, future.

Under eternalism, such words are only relations, like Earth, 1927 is in the future of Earth, 1925.

Please enlighten me as to the difference between Eternalism and the Moving Spotlight theory. — Luke

Moving spotlight (and pretty much the rest of your list) has a preferred moment. Eternalism does not.

You seem to be implying that temporal passage is possible under Eternalism? How so?

I implied no such thing. I said there is movement. I made no reference to temporal passage, which again is a term only meaningful to views that posit a preferred moment.

The mug moves probably by me carrying it there. That's probably not the answer for which you're looking, but I don't know what else you might be asking with that question.

I wanted to lay out my view of why Eternalism logically precludes motion. — Luke

I smell a begging argument coming on. You did this fairly large post, but then never actually get around to this point until the last couple sentences.

Some members of this site, including SophistiCat and @Douglas Alan have previously claimed that Eternalism does not preclude motion.

You can add me to that list. At noon, the mug has coffee in it. At 1pm the mug is in the dishwasher. How is that not motion of the mug?

In that case, my question is: when does motion occur according to Eternalism?

Somewhere between noon and 1 obviously (in my example). Every moment of it in fact, since at no time is any object actually stationary, what with Earth spinning and accelearting and all.

It cannot be at the present moment, because motion or temporal passage at the present moment implies the A-Theory, making it not Eternalism, but the Moving Spotlight theory instead. So, does Eternalist motion occur in the past or the future somehow?

There's the begging I smelled. Everything here are A-series references which assumes the conclusion you're trying to demonstrate.

Firstly, I don't know if communication per se is an indication of consciousness meant here as the existence of an inner life - what is it like to be something. — TheMadFool

I don't think there's anything 'being' me, so does that mean I shouldn't consider myself conscious?

The great Albert Einstein postulated that the velocity of light is constant at approximately 300,000 km/h. This one postulate and maybe a few more is the allegedly the foundation of his theory of relativity, a theory that has withstood many attempts at disproof. So far so good. — TheMadFool

It's 300,000 km/sec. It's a speed, not a velocity.
The postulate of SR is that that speed will be measured regardless the reference frame used. It doesn't actually posit that the speed actually IS frame invariant, just that it will be measured that way.

Consider 2 cars, A and B, moving on the same practically straight freeway.

1. Situation 1: A is moving at 20 km/h north and B is moving 60 km/h north. The relative velocity of B with respect to A is 60 - 20 = 40 km/h.

Per Einstein, no. Close, but not exactly 40. For instance, scale up the speed to say 0.2c and 0.6c, and the relative velocity of B with respect to A becomes 4/9 c, not 0.4c.

What then of the postulate that the relative velocity of light with respect to an object is "constant"? If I'm travelling in a spaceship with a given velocity, the relative velocity of light with respect to my spaceship will be 300,000 km/h. If I were then to alter my velocity, doesn't the velocity of light have to change accordingly so as to ensure that the relative velocity stays at a constant 300,000 km/h?

Unintuitive, but no. Light speed (not velocity) remains at c relative to anything. This works out if you use the velocity addition formula instead of straight addition like you're doing all through the OP.

Several of the questions presuppose the idea that minds can exist separated from the body. — Harry Hindu

Well yea, since the OP opens with: "If the mind is immaterial:"
The post asks to explore the viability of the alternate POV where there are two separate things, or where matter supervenes on mind. Given the wording of the post, I'd say more the former of those two.

I ask, "What is the point of a mind separated from a body?"

Or the point of a mind not consisting of a body?

All the above post seems to be about the mind being a function/process of the brain (or larger self), and sure, I am on that side of the fence, but I think the OP was asking about the opposite, where the body is a byproduct/purposeful-extension of the mind. The body seems to poorly implement such a purpose.

I've stayed out, and I find the arguments by unenlightened to be on point.
Nevertheless, the discussion seems to have turned to how materialism explains itself, and the original purpose of the OP seems to have been lost.

I think most of the relevant replies came from Wayfarer, but much of that was dropped. The Lusthaus quote was interesting but does not seem to address the question at hand. OK, it seems that it is a mistake to model the relationship as 'mind as an object'. We instead work with ideas and purpose, and the physical world is derivative from it. But then suppose it was my idea to take my purpose of needing an vehicle to animate my need for getting around and experiencing the world. Given that purpose, why would I imagine a vehicle with zero controls, that goes where it wants, when it wants. That's pretty useless for my purposes. I'd give it pedals and a steering wheel so that I could exert my will upon it. A physical being seems to have no pedals and such. It doesn't seem to be the product of the sort of purposeful ideas posited by this non-primary-material model.

What I'd like to say about that, is that both mind and matter are idealisations or abstractions. There is neither mind as a 'substance' (in the philosophical sense), nor matter per se because all matter has particular attributes and characteristics which define its type.

So whilst I agree that there is no 'immaterial object', I'm also inclined to believe that there are no 'purely material' objects either. — Wayfarer

I actually agree with this. On that point:

And then you've still got three ducks but now you've got a row as well. Assume the ducks are material. — unenlightened

If the row isn't 'new stuff', then neither are the ducks, being themselves just more arrangement of stuff that was already there. At what point is there actually stuff? It seems the scientists have never found it, and hence the unstable foundation of what is typically exemplified as 'materialism'.

Anyway, I was hoping to see more discussion on this original intent of this thread.

Near as I can tell, you mean something like 'coordinate time' when using the phrase 'relativistic time'. Coordinate time and physical (proper) time is the same thing for an inertial worldline with the time axis of the coordinate system aligned with said worldline.

Sure. But as you note later, proper time can be well-defined even in the absence of anything to mark its passage, and that is where I see a problem. You could have a relativistic spacetime with nothing else, and formally it would still have time of every description. But would it be physically meaningful? — SophistiCat

No, time without change is meaningless, as is say motion of an object in the absence of other objects. The words might as well be invisible pink unicorns.

Of course, here we run into the more general question of the nature of the physical law. Are laws ontologically prior to things and events that are subject to them? Do they describe potentialities (like what would happen if that empty spacetime did have something in it to demonstrate its relativistic properties)? Or do laws serve only to connect the dots, describe the regularities in our observations? In the latter case - and only in the latter case - it would be unjustified to talk about time in the absence of anything that is time-like. I think I lean towards the Humean regularity view.

I seem to be in the latter camp. Spacetime with nothing in it doesn't have relativistic properties.

The reason we came up with the theory of relativity in the first place was to give a better account of clock-based time (among other things). Without clocks what is the point of relativity?

Can there be time without clocks? Surely there are primitive people and animals with an awareness of time, but they also arguably have clocks, however inaccurate. If the speed of light was a lot slower, its properties could be more apparent and intuitive to primitive beings who may not have developed accurate measurements for it yet. Similarly, our intuitive perception of time as flowing is only there because that perception makes us more fit, not because time necessarily flows.

An empty, flat spacetime with a positive cosmological constant is an interesting case.

Meaningless. If it has stuff, I don't think it can be flat. If it were, an inertial frame could foliate the space, and it cannot.

relativistic time is not identical to physical time (the time that physical clocks measure) — SophistiCat

Actually, you never really defined what you mean by 'relativistic time'. You say physical time is that which clocks measure. I think physics would say that a clock measures proper time, a frame independent property of any timelike worldline. Clocks, not being confined to a single point, cannot be perfect, just like the exact length of a curving road is ambiguous because the road has nonzero width.
I digress. What do you mean by relativistic time? You said the two are usually the same except after heat death, but that doesn't tell me what you mean by the term, especially since a clock cannot exist in heat death conditions. It seems that time in general (both duration and direction) fade to meaninglessness along with most other physical concepts.

If I take a cube, and divide it in half, and then again, ect to infinity and then line them all up biggest to smallest, what is the smallest? ...
You might say "there is a limit". — Gregory

I might not. You're the one making the suggestion and then driving your own assertions to obvious nonsense conclusions.

So we have a huge paradox here.

Exactly so. So maybe try it without positing a last term in the infinite series.

Does the series go off into the physical horizon forever?

Physical now? A physical cube-shaped object has a finite number of particles in it and can only be divided so many times. There is a smallest part at the end of the sorted line and it has a color if you're going to abstractly assign colors to the even and odd ones.

Except that there is actually no motion according to Eternalism. I would imagine that it's much easier to explain why we perceive motion if there actually is motion than if there actually isn't. My point, again, is better expressed by Kristie Miller:

For the eternalist, the key challenge lies in explaining temporal phenomenology and in explaining the apparent directionality of time. There has been significant work in this area, but questions still remain: why do we have such a different relationship with the future than with the past: why is it that effects typically precede their causes when the laws of nature are symmetric: why do we remember the past, but not the future: why does the present seem to us to have a particularly salient quality that other moments lack; what are the cognitive apparatuses that underlie our experience of
temporality and how do they function to create temporal phenomenology; what is the evolutionary significance of the phenomenology of temporal flow and to what extent is the phenomenology of temporal flow essential for agency.
— Kristie Miller — Luke

I think I'm up to that explanation, which, from a physicalist point of view, can be explained through entropy and evolution, but almost nobody actually accepts physical monism deep down. I think I have but it was a multi-year struggle to shake off the biases put there by a very proficient liar.

So the story from the dualist POV (there is an (physical or spiritual, doesn't matter) identity 'I' that consistently experiences the life of physical body X. The analogy here is that physics is like a first person Harry Potter movie and the experiencer is the guy in the cinema. Eternalism is the same thing, except no cinema, no entity watching the show, and especially no projector.

Under presentism, the present is whatever frame is currently being projected. Normally the film runs front to back, but if it were run back to front, the experiencer in the cinema would notice the difference but Harry would not. The movie would end with the guy in the cinema knowing Harry's life story (the future) but Harry wouldn't even know that he's a wizard at the end. Harry obviously has different memories than the guy in the cinema. So the movie always runs forward because we'd be able to tell if it didn't.

Hence it being totally unintuitive to such a dualist to conceive of eternalism, which requires the lack of the experiencer (the definer of the present), and he interprets the description (the word 'static') as the experience of a stuck projector. The view is anything but that.

The eternalist view has no experiencer. It doesn't even have Harry (as an identity). It only has the individual frames in the film and one can talk about the experience of that frame, and yes, the experience of any given frame is one of motion of the passing car. One is forced to use B-series language to express what each frame experiences because there is no preferred frame defined by a projector, and A-series requires that preferred reference. By 'frame' here, I'm talking a frame of film (the local state of things at a particular time), and not relativity's reference frame.

The subjective flow of time is an illusion, illustrated empirically with the twins scenario in relativity. If people could detect the actual flow of time, then they'd be able to detect movement due to the subjective slowing of clocks when they're moving fast, whereas if it were an illusion, any traveler would notice no difference.
— noAxioms

It's unclear to me what the illusion is that you are referring to. What 'movement' is going undetected? What 'movement' would be detectable if "people could detect the actual flow of time"? — Luke

Not movement. I refer to the rate at which the present moment progresses into say a moment one second hence. No device measures this, and the subjective experience of a human is no exception to this. If there was, one could design an objective clock that would stay in sync with any other objective clock regardless of where it was or how much it has been accelerated around.

How to interpret data is subjective. The sole thing Einstein noticed was the observation that external motion changes the size and some of the rate of change within the object. That's it. — Gregory

This is totally wrong. The sole observation from which Einstein did his SR work was the apparent constant speed of light. From that, all the things above were predicted, not measured ahead of time.

Since he didn't do the experiments, he probably didn't even come up with that.

Indeed, he didn't do them himself.

Do you deny that it is unintuitive to be able to divide something finite a literal infinite amount of times? — Gregory

For one, 'infinite' is not an amount, and 'literal infinite' is no different than 'infinite'.

I would instead find it unintuitive to suggest that there would be a limit to it, a pair of non-identical points for which there is not a location between them. To assert otherwise is to assert that two non-equal numbers A and B can be found such that (A+B)/2 is equal to either A or B or both. You have weird intuition.

So I would say that a finite segment can be divided without limit, and yes, this is intuitive to me.

This is not true of any discreet system. For instance, in the domain of integers, the finite segment from 20 to 6051 can be divided, but only so many times. There is no integer between 21 and 22, and (21+22)/2 does not define a new integer, nor is the answer necessarily equal to either 21 or 22. It might be, depending on how the divide operator is defined for the discreet set in question.

According to the Kristie Miller article cited in the OP, the difference between Presentism and Etetnalism is not only their differing views on existence, but also their staticity/dynamism. — Luke

Miller writes this:

Thus eternalists endorse the following pair of theses:

Eternalist Ontological Thesis (EOT): Past, present, and future times and events exist.

Static Thesis (ST): The present does not move: which moment is the present moment does
not change. — Miller

Now either Miller has no understanding of the position, or she's talking about something completely different. The view denies the existence of a preferred moment called 'the present' and hence the ST part is nonsense. I've actually heard of such a view, which is presentism without the movement, but Miller doesn't seem to be talking about that since she correctly states that all events at all times exist equally, which is not true of a model with a present that stays put like that.

Anyway, I'd never accept these points as worded. The first isn't totally wrong, but past/present/future are all relations like < = >, and not objective states like negative, zero, and positive, and the wording makes it sound like the latter.

Then I take it you agree with all of the following:

Eternalists, then, hold that the world as a whole is static in two senses: which events
exist does not change, and there is no sense in which the present moves. — Luke

I'd say there is no 'the present' to do any moving. 'The present' would be just any event's self reference, and that, by definition, cannot move.

Eternalists accept what is known as the B-theory of time. This is the view that the
world is a static block of events ordered by the earlier than, later than, and simultaneous
with, relations. [1]

Also known in physics as 4-dimensional spacetime. 3D Space and time are separate under presentism.

Presentists endorse the A-theory, since they hold that it is a genuine feature of a
presentist world which moment is present, and that this fact changes over time so that
different moments are present at different times. To say that a view accepts the A-theory
is really to say that it endorses the dynamical thesis, and to say that it endorses the
B-theory is to say that it rejects the dynamical thesis.

I haven't seen the dynamical thesis, but this seems right.

Eternalism, on the other hand, is a static view that rejects temporal flow. Since it certainly
seems to many that there is temporal flow and change, this is a cost to eternalism.
At the least, the eternalist owes us an account of why it s

The subjective flow of time is an illusion, illustrated empirically with the twins scenario in relativity. If people could detect the actual flow of time, then they'd be able to detect movement due to the subjective slowing of clocks when they're moving fast, wheras if it were an illusion, any traveler would notice no difference. This of course isn't easy to test given the cost of the experiment, but it is there.
No, it isn't a proof of one view or the other, just a demonstration that the flow of time is a subjective illusion.

The odd numbers are eternally half the natural numbers, so there is no way at infinity they can be equal. — Gregory

I can think of at least 3 things very wrong with this statement. For one, what's the difference between X being half Y and X being eternally half Y? I mean, 5 is half of 10, and no matter how long I wait, 5 will remain half of 10, so I suppose it is eternally half of 10, but saying it that way doesn't make '5 is half 10' more true.

Let's see... There are 100 natural numbers with magnitude less than 100, and there are 100 odd numbers with magnitude less than 100, so that's not what you mean by this statement.

2nd try... Half of the natural number 36 is 18, which is not an odd number, so the odd numbers are not the halves of the natural numbers (whereas the integers would be half the even numbers, interpreted this way). So anyway, I don't think you meant this either, but I'm out of ideas.

And where is 'at infinity'? That's the treating it like a number that leads to such nonsense statements.
Surely Kant didn't make any such statements. Your intuitions lead to contradictions it seems.

If you can subdivide a segment endlessly, to eternity, it's finite and infinite.

What, exactly, is finite and infinite? Subdividing a finite segment doesn't affect its total length, so its finite length is unchanged. Also, what's the difference between 'endlessly' and 'endlessly, to eternity'? That's twice you've used that redundant modifier like it means something different than its absence.

It has to do with relativism because something can't be both finite and infinite at the same time with respect to the spatial, yet it is so. — Gregory

What is both finite and infinite? The length of AB is finite, and is never infinite. The number of points that can be described along AB is not finite, and is never finite, hence the existence of the bijuntion between that segment and any other. Neither is both finite and infinite.

Is this just another version of those threads that treat infinity like a number and then draw contradictions?

Anyway, I still don't know what this has to do with relativism, a view that seems to have nothing to say about the sort of mathematics you're discussing here.

As always, it's impossible to tell when someone claims to represent opponents' arguments made elsewhere, whether they are doing it accurately. — SophistiCat

Case in point:

it always amazes me that proponents of Eternalism so readily accept the static , motionless nature of their own temporal landscape. I'm no scientist, but much of science appears to be reliant on a dynamic world involving rates of change, momentum, spin, acceleration, velocity, etc. — Luke

I don't think the typical eternalist would assert a motionless landscape. An object is here at time zero, and over there at time 1, thus there is motion, spin, acceleration, velocity and all that.

Except that an arrow of time assumes a dynamic world? — Luke

The block view does not lack dynamics. The arrow of time kind of assumes that view since I don't see how you can draw an arrow in a direction that is posited not to exist.

Bijection has nothing to do with length. That just indicates that no line segment necessarily has more or less individual points than another. Length is not a count of points. Your fallacious thinking is in treating points in a line segment as a finite number.

1) Slant has no effect on the concept of bijection
2) Points are points, and don't have another shape.
3) whatever
4) Points don't have a size, so no.

I don't see how any of this is related to relativism

Are there other minds, or other bodies? — Harry Hindu

Only actual antirealist position I can think of is outright nihilism, and from what I understand of that, no, minds and bodies (not even ones own) exist.

I was referring to metaphysical antirealism which is the idea that "nothing exists outside the mind". — Michael McMahon

Since this topic was resurrected, I want to point out the contradiction of antirealism, defined in the OP as "denial of the existence of an objective reality" and the statement quoted here of "nothing exists except X" where X is the mind in this case. Those two definitions are mutually exclusive, the latter being a form of realism typically knows as idealism, which posits the reality of experiences.

I personally have found 'existence of an objective reality' to be a meaningless concept, and hence see no reason to assert it, which is a little different than actively denying it, so I'm not sure if I qualify as an antirealist.

I think the philosophical preference of a physicist, one who knows what he's talking about, typically has better grounding than a similar opinion from someone less familiar with the physics involved.

I for one know my physics enough to know that I've never seen an empirical falsification of either interpretation, and hence any logical argument must proceed from non-empirical assumptions. I've done that process and concluded what I conclude, but my stance keeps changing as I learn more, so the odds that my current favored view corresponding to 'the way that it actually is' (if there is such a thing) is pretty minimal.

But what's the relationship between the block universe (a physical model) and the metaphysical interpretation of time? — Echarmion

Sorry, but I consider them to be the same model, both metaphysical interpretations of space and time.

the answer to every philosophical question becomes "Because God Says". — Banno

Is it always 'because God says'? Take some moral rule X. Is X a rule because God says, or does God say because X is really wrong? The former denies objective morals. If God said one must light a live puppy on fire at least once a month, then that's the rule, but a rule relative to God, not objective.
The latter would be God forbidding lighting live puppies on fire because that's just wrong, implying there's a higher authority than God.
How is this resolved? I resolve this by denying both.

My stance on this topic is well known. While an eternalist, I've started an advocatus diaboli thread on the old PF defending presentism. There's no falsification test for it, and thus relativity theory doesn't demonstrate the topic one way or the other.

OK, you didn't say 'demonstrate', but it very much suggests it anyway. The vast majority of non-religious physicists that know their relativity (many (most?) probably don't) hold a block view. The view is semi-incompatible with the promises of major religions, and thus meets significant resistance without actually admitting the reason driving the resistance.

Sounds like the truth of any set of propositions being equated to the mutual validity of the propositions. I'm pretty open to that, although it seems to reduce the meaning of 'truth' to the meaning of other words like 'validity'.

Before we move further, I have a quick question about something you suggested relative to infinite regress and logic (my interpretation anyway). And that is, are you thinking the concept of a 'God' is an infinite consciousness/energy rather than some logical axiom? — 3017amen

Not really my place to define God, despite me being raised that way. What's that got to do with logic and infinite regress? My philosophy is currently a relational one, so that removes the need to solve any sort of something from nothing sort of scenario.

Which would, in theory of course, make it [consciousness/the Will] metaphysically necessary v. logically necessary.

I don't follow that at all.

Can you kindly explain what you mean by this? Why is the answer always "yes"? — TheMadFool

It only works with my definition, for the reason I explained in the part you quoted.

Gosh, there's so much information to unpack... If it's okay with you let's take one question at a time and then perhaps we can build something from there.

1. Whether it is logically necessary that there is something rather than nothing, or there's an infinite regression of turtle power, there will always be a question concerning an original or initial cause and/or origin of life, thus the Kantian judgement: all events must have a cause. — 3017amen

Kant is seemingly wrong then, because uncaused events have been demonstrated (well beyond Kant's time), although there are interpretations that posit hidden variables (that cannot be known) that are responsible for such things, so it isn't cast in stone I think. As for the structure that seems to be our universe, there's no particular reason why time should or should not be bounded at one end or the other. There's no entropy level to order it outside our own spacetime, so any cause that comes from there is arguably an effect since there's no particular relationship of cause->effect without an arrow of time. There's just potential bounds which can arbitrarily be labeled first and last.

I'm kind of quoting what little I know. I'm hardly an expert, but my takeaway on the subject is to not apply the laws of our spacetime outside of that spacetime, and positing the necessity of this 'original cause' is doing just that.

I don't see how any of this relates to free will. My view on the above topic is that the universe is not caused at all. It implies there was no universe, and later there was, which is absurd if time is part of the universe.

To further parse Will from Free Will though, I believe having a will implies consciousness or intelligence.

I know plants that seem to have a will, but by the same argument you can paint them as having consciousness as well then. Intelligence? That's a stretch...
I know of machines that have intelligence, but they're almost all slaves, so their will is not their own.
Anyway, consciousness (and probably intelligence as well) are about as poorly defined as free will, so your comment doesn't really help.

Should we try to redefine the meaning of Free Will?

You defined it quite precisely the last attempt. You want to abandon that? I just thought it a funny name to give to what seems to me to be the opposite effect.

First, can we agree on a few items:

1. Free will: a source totally detached from matter (detached from nature) which is the origin (cause) of
options, thoughts, feelings,... That is, the absence of (natural) laws, the existence of an "autonomous
mind", i.e. a principium individuationis. — 3017amen

What does 'original cause' mean? Most effects (I can think of no exceptions) are a combination of countless causes, the absence of which would likely have prevented the effect. Thus none of them is designated as being more original than any of the others.

Anyway, your definition sounds like something undesirable. Dewey possessed by his supernatural demon is the only guy who cannot do what he wills, and thus has free will. Read about Dewey 5 posts back if you don't know what I'm talking about.
Anyway, yes, I often hear free will defined something like that. I don't think I have that, and I certainly wouldn't want it. My definition doesn't work well either, because I cannot do everything I want to do.

Quantum mechanics is indeterministic but it is not a-causal. There is always a cause, an explanation or reason, for any phenomenon

Disagree. There are uncaused events, like radioactive decay, to name a simple one.

4. The opposite of free will is materialism rather than determinism (?).

Ah, there it is. Free will is not about freedom of will at all, but rather an assertion of a different mechanism (possession by a supernatural demon, as I phrase it) for said will. I'm not a materialist, but I also don't think I have the sort of free will you describe. Thus I'm not sure materialism is the necessary stance needed if one denies that sort of free will.

The dualism asserted implies free will only by definition, but does not demonstrate any greater freedom in what is willed since even if the will comes from non-matter, you still don't know if the process by which that supernatural will is implemented is any less a function of external causes other than ones self, than if the same process was implemented with matter. My street crossing example illustrates the sort of behavior resulting from will that is not a function of external causes beyond one's control. I cannot work that way since death would result in minutes.