Is time an illusion?

[helios]

Spacetime because they wouldn't happen without time. But space because that's where it takes place. Where it actually happens is space, and it affects time.

Sorry, but no. This interpretation is just incorrect. The universe and its contents are four-dimensional objects. They exist in spacetime, not solely in space or time. Grab any physics book from the twentieth century and this is how the universe is understood.

Not true, space would exist in that moment where it stopped. I'm not saying time has disappeared, I'm saying time has stopped progressing. The moment would be captured perfectly, an unchanging image of the universe. Argument still stands. Time can stop and space will continue to be there, but without space - time would have no place to exist.

I see what you're saying. You're interpreting the universe as a video. The image on the screen is space and playback is time, and once the video gets to the end you can view the last image as a still.
The issue with this is that for this analogy to be applicable, there needs to be another time dimension at least partly independent of our own universe's time. It doesn't make sense to talk about "changing" or "unchanging" when there's no time. If there's more than one time dimension (say, time1 and time2), an extra-temporal1 being could observe the end of space-time1, while occupying in space-time2, as indeed a still picture.
But we don't know if time2 exists and there's no way to test for it.

The issue is that it IS obvious. Very obvious, but it can't be proven without a doubt. The point is that any logical thought would lead to this conclusion and what evidence there is would also point to it. However, there's always the chance that it's wrong, and that's what you're arguing even though there's no reason to. The whole world could simply be a projection of our minds and not actually existent, but it's healthier to think the world is actually real - and a lot more probable.

I'm sorry, but what? The quote you're responding to relates to the question in semiotics of whether there exist some things that cannot be named. What does that have to do with sollipsism?

Am I mentally retarded? "We don't and we can't know." Did NASA fake the moon landing? "We don't and we can't know." Was Trump elected? "We don't and we can't know." -- By using the argument that we can't possibly know anything, suddenly you have answers to nothing.

You can know nothing with absolute certainty, but if you start from the assumption that at least your senses are more or less trustworthy, you can reason that when things happen they leave behind evidence and you can look for that evidence using your senses. If you can find enough evidence you can build a strong case that the event in question did indeed happen.
Hypothetically, nothing prevents you from building a rocket, putting a probe around the Moon, and taking photographs of the Apollo 11 landing site. I don't think anyone could dispute that evidence to themselves.

However, the question of sollipsism is different. You're trapped inside your own brain, and the only contact to the outside world is your senses. You have no means to obtain independent evidence that the world is indeed as your senses tell you.

If we IGNORE all this to simply say "we don't and we can't know," simply because we can't prove it beyond impossible to disprove doubt, then I don't know what to say.

I agree with you. It would be unreasonable to doubt time dilation given all the evidence we've gathered to support it.
Assuming the world is as we perceive it.
That we can measure time dilation gives you no information on the question of whether time is an illusion. The question pertains to the accuracy of your senses, which are the very thing you're using to read the measurements. If you don't trust your instruments then any measurements you take with them are unusable to reach any conclusion. You can't prove that your intruments are reliable by using them to take measurements.

It's much like "last thursdayism." Sure, we can't disprove it, but things like ockham's razor and such serve to disprove these undisprovable/unprovable theories.

You're confusing Occam's Razor ("given two explanations for the same phenomenon with equal predictive power, prefer the one that makes fewer assumptions") with Popper's answer to the demarcation problem ("an unfalsifiable claim is outside the scope of science").
Any metaphysical hypothesis is obviously unscientific, but I think it's difficult to say whether Last Thursdayism assumes more things than other hypotheses about the nature of time.

I feel like you hate me a bit more with each reply!

Nah, I love a good debate. Some people get emotionally invested in their positions, but that's just not me. Unfortunately I've gotten into fights with people who can't do the same and take simple rhetoric as a personal attack.

[zapshe]

Sorry, but no. This interpretation is just incorrect. The universe and its contents are four-dimensional objects. They exist in spacetime, not solely in space or time.

This doesn't conflict my view. Objects do exist within spacetime, but their physical properties are in space. What I'm saying is that when things happen, it happens in space over the span of time. But space is where it physically is and time exists within space.

The issue with this is that for this analogy to be applicable, there needs to be another time dimension at least partly independent of our own universe's time.

I see what you're getting at. But that would only be needed to prove this analogy. I think it would be safe to assume that space would still exist if time were to stop. After all, moving at the speed of light means time is almost at a standstill, and it doesn't seem to eliminate space.

I'm sorry, but what? The quote you're responding to relates to the question in semiotics of whether there exist some things that cannot be named. What does that have to do with sollipsism?

My bad, must have read something other than what I quoted or something. With the color analogy, you simply have to realize that color itself doesn't exist outside our minds. There are different frequencies of light, but nothing in physics says that they have to appear the way they do to us. Every brain could theoretically perceive a different color. There's no way to describe a color so thoroughly that you can actually have that color appear in another's mind. Unlike things with more physical attributes, such as shapes. You can describe a cube enough for someone to be able to imagine it. I'm pretty sure this language limitation is well known.

However, the question of sollipsism is different. You're trapped inside your own brain, and the only contact to the outside world is your senses. You have no means to obtain independent evidence that the world is indeed as your senses tell you.

Yes, the argument is not provable or disprovable. However, it's generally healthier to accept that the world is real. There's no reason to sway one way or the other in sollipsism.

You're confusing Occam's Razor ("given two explanations for the same phenomenon with equal predictive power, prefer the one that makes fewer assumptions") with Popper's answer to the demarcation problem ("an unfalsifiable claim is outside the scope of science").

Yea, I didn't know which "rule" in particular it was, I was just naming one in general. Overall, I'm pretty sure we agree on the case of sollipsism, but I'm assuming it's false and you're arguing that it's still possible.

Nah, I love a good debate.

Glad to hear it!

[helios]

I think it would be safe to assume that space would still exist if time were to stop.

I don't think so.

After all, moving at the speed of light means time is almost at a standstill, and it doesn't seem to eliminate space.

We're not talking about relativistic time dilation. If you were to travel at c, your time would pause for a finite amount of stationary time.
We're talking about time ending. Just like how there's no time before the Big Bang, there's no time after the End of Time. Was there space "prior" (whatever that means) to the Big Bang? Is there space "after" (WTM) the End of Time? I don't think so, not if the universe has only four dimensions.

nothing in physics says that they have to appear the way they do to us

On the contrary. Consciousness is an entirely physical process. Your color perception is direct consequence of physics and the physical layout of your brain. There's nothing not physical the way your perceive color. If you think there is, well I'm sorry, but I don't feel like arguing about dualism and materialism.

There's no way to describe a color so thoroughly that you can actually have that color appear in another's mind.

This is just because our knowledge of the brain is incomplete. What we do know is this:
1. Light can be objectively measured.
2. To measure color the eye works analogously to a digital camera, in that it uses three different types of sensors to measure the intensity of light in three partly overlapping wavelength ranges. (The eye also has rod cells which are more sensitive in low light and are also more sensitive to motion, but can't perceive color, but they're not relevant to the question of color perception.)
3. The brain is capable of remembering colors, and even distinguish changes in shade compared to memory, so it must encode color information in some physically objective way, so it can be processed by different areas of the brain. We don't know exactly how this happens or whether different people encode the same information differently (assuming they don't have brain damage or some other abnormality).

Given what we already know, I see no reason why knowing in full detail how the brain works would prevent us from communicating subjective experiences. Yes, we can't do it now, but that's hardly evidence for it being impossible. 200 years ago sending cat pictures across the globe at ~20% the speed of light would have been unthinkable.

EDIT: By the way, this might interest you: https://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time)
Basically it's the idea that the universe is not a process changing its state over time (so neither past nor future exist and only the present is real), but actually a sort of four-dimensional sculpture, where all instants in time are equally real. By this interpretation, our perception of time would be an illusion, but in a different way. Actually we assume that only the present is real because that's all we can perceive. Imagine if you could perceive one hour around your present location.
You might arrive somewhere and see a dead body, and glance back and see the murder happening half an hour ago (the murderer may also see you arriving half an hour from then). The only instance in fiction I can think of of this concept being used is Dr. Manhattan, and his power is a bit inconsistent, unfortunately.

[George P]

So much depends on whether the discussion of time is about absolute time or relativistic time.

[helios]

Relativity of simultaneity (there's no objective way to order causally unrelated events) implies that there's no such thing as absolute time.
However, we can still talk about time ending in all frames of reference. This would be the case if a Big Crunch happened.

[zapshe]

I don't think so. We're not talking about relativistic time dilation. If you were to travel at c, your time would pause for a finite amount of stationary time.

Yes, bad example, my bad. However, I think it would be logical to assume that the existence of space is not dependent on time. What reason would there be for space to not exist if time stopped or ceased to be?

On the contrary. Consciousness is an entirely physical process. Your color perception is direct consequence of physics and the physical layout of your brain.

There's no contradiction. Yes there is only the physical aspects of our brains which process this. The genes within us play the role of how these things will be implemented. People who are color blind have something physically wrong. However, there's no physical aspect in the universe saying that these light frequencies have to be the color label our brain gives it. Vsauce video on this - https://www.youtube.com/watch?v=evQsOFQju08

This is just because our knowledge of the brain is incomplete.

Yes. I don't remember what argument led us down this one but all I was saying is that language as it is now is too limited to go as far as to describe a color in a way to make it appear in one's mind. I'm sure there is some way that it's possible, but not through language as it is now. Language wouldn't be able to provide the brain enough knowledge for it to be able to actually envision a color never seen before.

By the way, this might interest you: https://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time)

I've never read about it and I don't think I fully understand it. It didn't peek my curiosity though. I've watched a lot of anime and played a lot of games that mess around with different ideas of time. Thanks though!

[367kGNh0]

games that mess around with different ideas of time

A game in which you can actually create a paradox would be quite entertaining. Just a first-person game where a few minutes before spawning you finished a time machine, go in, play for a while and after 30 minutes there are 40 "you"s in the present. Such an occurrence would be depressing if the time machine breaks. "You" would live to see eachother die

[helios]

What reason would there be for space to not exist if time stopped or ceased to be?

Let's go back to my canvas analogy. Imagine a canvas of 1 m x 1 m. If you're at the top left corner, you can say there's 1 m of height below and 1 m of width to your right.
If you move 50 cm to the right there's still 1 m of height, but now there's 50 cm of width on each side.
If you move another 50 cm again there's 1 m of height, but no width to the right. If you move 1 cm to the right you're no longer in the canvas; there's no height.

Yes there is only the physical aspects of our brains which process this. [...] However, there's no physical aspect in the universe saying that these light frequencies have to be the color label our brain gives it.

You're contradicting yourself. The reason you perceive red the way you perceive it rather than any other way is because of the way your brain is wired up. This is a physical phenomenon. If you disagree then please explain what you mean by "physical aspect in the universe".

Yes. I don't remember what argument led us down this one but all I was saying is that language as it is now is too limited to go as far as to describe a color in a way to make it appear in one's mind. I'm sure there is some way that it's possible, but not through language as it is now. Language wouldn't be able to provide the brain enough knowledge for it to be able to actually envision a color never seen before.

I made this clarification in my initial statement.

Whether it's possible for there to be real things that cannot be (not are are not) named is a debate in semiotics.

Obviously there are things for which we have no name; for starters, everything we don't know about and haven't even imagined yet.
The question in semiotics is whether there are things that cannot be named (or, equivalently, communicated).
It's about the power of language. It's similar to how the Church-Turing thesis talks about the programs that are computable by a Turing machine, not about the programs that currently exist.

[367kGNh0]

don't know about and haven't even imagined yet.

In other words the things we don't know that we don't know?

[zapshe]

Let's go back to my canvas analogy.

This seems to support my theory. Height and width only exist within the canvas (when speaking relative to the canvas) just as how time exists within space (have we come to terms on that?). So since they are aspects of the canvas, they don't cease to be when we're not on the canvas. If we "exited" space, then there is no time, at least not the time that we were just experiencing within space. However, I don't see how "exiting" time would mean that you no longer are within space. Supposedly, when you say that when you're no longer on the canvas so there's no height, its the same as if you're no longer in time so there's no space? If so, I don't find that to make much sense.

We are constantly moving through time, but not necessarily space (though we are we don't have to be). As you move closer to the speed of light, you will physically experience less time (Ex. age less). Thousands of years may pass by, but to you it would have been a mere moment. Time fluctuates in a way (lack of a better term), its very nature is affected by what happens in space (it passed differently for different people). People will end up in their destination as if little to no time has passed while generations of people have lived and died. However, even when time is affected in this way and such, the fabric of space doesn't seem to be affected by time.

You're contradicting yourself. The reason you perceive red the way you perceive it rather than any other way is because of the way your brain is wired up. This is a physical phenomenon. If you disagree then please explain what you mean by "physical aspect in the universe".

Let us separate colors from their respective light range frequencies for a moment. Lets say a light frequency hits your eye and you experience red. The same frequency hits another's eye and he sees blue. This would be because of how the brain is wired, each individual saw a color that their brain is wired to label with a certain light frequency. But that's your brain doing that, there's no law of the universe governing whether you should see certain light waves as certain colors or not. So because of this, you can't know whether two people are seeing the same color or not when shown the same light frequencies. We could both look at a color, call it red, then walk away never knowing how different our experiences really were.

I made this clarification in my initial statement.

Yea, I was agreeing with you xD, just restated.

The question in semiotics is whether there are things that cannot be named (or, equivalently, communicated).
It's about the power of language.

I have no doubt that with the right technology we could probably communicate anything which we know of to another person. Given the right electrical signals, one could be given an experience that didn't actually happen or information. This would be communicating in a way. Even differences in how our brains may process things differently (as with my red color example) may be taken into account and used to alter the signal as to give an experience almost exactly the same as the original. So the question of whether or not it's possible to communicate color wouldn't be a debate in semiotics for our case, since it's theoretically possible and this is more about how we can't communicate it through current language.

[helios]

Height and width only exist within the canvas (when speaking relative to the canvas) just as how time exists within space

In the analogy, the canvas is the universe (or spacetime), width is time, and height is space.

So since they are aspects of the canvas, they don't cease to be when we're not on the canvas.

You need to be careful when using words like "cease", which are time-relative. It sounds like you're assuming that your own time, as an observer of the canvas, is orthogonal to the canvas' time (width).

Supposedly, when you say that when you're no longer on the canvas so there's no height, its the same as if you're no longer in time so there's no space? If so, I don't find that to make much sense.

I honestly don't see how this is complicated. A canvas is a surface; a region of two dimensions. If you reach an edge (the extent of one of the dimensions) the canvas ends. The canvas exists only within its boundaries. Width and height are measurements of contents within the canvas. If you go outside the canvas there's nothing to measure.

Extend the canvas to three dimensions, and it's a cube. Again, the cube exists only within its boundaries. Width, height, and depth are measuments of regions within the cube, they're meaningless outside it.

Now extend the cube into four dimensions and call the last dimension time. The idea is the same, time is just another dimension for an four-dimensional object to occupy, along with the other three. If you move far enough along any dimension that you cross the boundary of the tesseract, it's not just that there's no space. You're outside the tesseract; outside of spacetime. Nothing can exist in this region, at least as far as humans understand "existence".

However, even when time is affected in this way and such, the fabric of space doesn't seem to be affected by time.

I've gone over this already. Gravity and motion are phenomena in spacetime.
Gravity affects both space and time: space bends causing gravitational attraction and time bends causing time dilation.
A macroscopic object moving a relativistic speeds not only finds its time dilated, also its space is compressed along the direction of travel.
https://en.wikipedia.org/wiki/Length_contraction
Neither space nor time affect each other. Spacetime as a whole is affected by the particles it contains.

I'm sorry, but you're just plain wrong. Understanding time as being "inside" space (or vice versa) is just incorrect. Time and space are dimensions (well, sets of dimensions) of spacetime, which is, in technical terms, a four-dimensional manifold.

But that's your brain doing that, there's no law of the universe governing whether you should see certain light waves as certain colors or not.

But the brain is doing what physics says it must do. What do you mean "there's no law"? If you build a camera that maps red to FF0000 and green to 00FF00, the thing that causes it to work is physics. Maybe you might say "no, it's your design that makes it work", but you didn't design it in a vacuum, you used your knowledge of physics to do it. The brain likewise evolved to take advantage of the laws of physics (namely electricity and chemistry).

PS: I'm not responding to the rest of your post because we're basically in agreement.

[zapshe]

In the analogy, the canvas is the universe (or spacetime), width is time, and height is space.

I see, that makes more sense. So if you leave the canvas either through width or height (time or space), you've also gotten rid of the other since you'd leave the canvas (the universe) entirely. But I don't feel like this is working analogy for this case since both width and height deal with space itself.

Here's another comparison. Suppose you have a room full of Earth air and you remove the oxygen. There's still air in that room, it wasn't dependent on the oxygen. The air is still made up of other things. However, take away the air and you've gotten rid of oxygen.

However, if I implement the analogy the way you did, it would be quite different. Imagine being in that room full of air. If you somehow found a way to escape the room (just as how you'd leave the canvas if you went "beyond" the allowed width), then by default you've also escaped all the air, which would also be space. If time exists within space, being separated from time doesn't mean you've separated from space. But in your analogy, the way to leave time is the exact same way to leave space, which I guess is the point.


I'm not in a great mindset at the moment and I'm not sure where I was going with the stuff written inside {}. Some of it seems a bit off and subject to the chicken and the egg argument.
Slightly Full of Shit:
{
But consider this. Instead of seeing the tesseract's 4th dimension as something you can "cross", consider if it disappeared all together. The other dimensions don't vanish! If I take away a dimension from 4th dimensional object, it collapses into a 3d one. But which dimension did I remove? Answer: It doesn't matter. It'll collapse into a 3d form anyway, which will consist of a cube. This shows that you need those other dimensions before you can move through time. Don't believe it would fall into a cube? Consider taking away, lets say, height from a cube. Now it's 2d, but what would it look like? It would only be a top or bottom. If you took away width, then it would only be the back or front. Take away length, and you'll only have the right or left of it. Either way, it'll become a 2d square. Meaning that the only way to build up to a 4 dimensional object is to have your previous 3 dimensions.

^Basically saying that an object needs to exist within space FIRST before it can move through time by order of dimensions.
}

Just because an object doesn't move through time, doesn't mean it doesn't exist within space (if time pauses, you wouldn't assume matter will disappear), whereas if we have an object that doesn't exist in space, we know it doesn't move through time (at least not as we know it in our universe).

I've gone over this already. Gravity and motion are phenomena in spacetime.

Gravity is caused by mass which exists within space and moves through time. Motion is mass moving through space over the span of time. Notice how in all of these, they exist within space and move through time. As we agree, without space there's no time as we know it now, but take away time and there's no real reason to think that space would also disappear.

Also, if space was as dependent on time as time was on space, would that mean the universe would disappear without time? If looking at the mass in the universe, without time they wouldn't exist. This would be because they need to exist at some point, you can't have mass that exists in no time. However, space itself doesn't have any limitation like that, it's empty space after all, it doesn't need to move through time to exist.

I suppose in the end nothing we're saying can really be proven though.

But the brain is doing what physics says it must do.

I think you're confusing colors as being physics. Colors have nothing to do with physics and don't exist outside of our minds. Different frequencies of light exist and our brain differentiates between them by giving them different hues. The reason we can't describe color in a way to make a blind man visualize it is because it has no physical attributes, which is what I mean by "there's no law". There is nothing in physics saying that those frequencies are that color, it's our brain differentiating. If we both look at FF0000 and call it red, we both may experience different colors while seeing the same frequency, because color is not guided by physics. If you watch the video I linked, it's explained pretty well. Color is an illusion and doesn't exist outside of our minds. Our brains convert certain ranges of light frequencies into the colors we experience. Those light frequencies themselves don't have a specific color "attached" to them.

EDIT: Slight corrections

[helios]

If you somehow found away to escape the oxygen, then by default you've also escaped all the air

What? But you just said, you can remove the oxygen without removing the air. Then if I escape the oxygen we can't conclude that I've therefore also escaped the air. I could be immersed a gaseous solution of nitrogen and trace gases that contains no oxygen.
I gotta say, though, I have no idea what you're getting at.

Instead of seeing the tesseract's 4th dimension as something you can "cross", consider if it disappeared all together. The other dimensions don't vanish! If I take away a dimension from 4th dimensional object, it collapses into a 3d one.

Yeah, but that's not what it means for time to end. If you take spacetime and remove time, the universe as we know it ceases to be, and to have ever been, completely and utterly. When I say that time ends I'm talking about reaching the end of file. You're talking about deleting the file. Those are two very different scenarios.

As we agree, without space there's no time as we know it, but take away time and there's no real reason to think that space would also disappear. Since like I said, take away that dimension of time and all you have is a physical object in space that is static in time.

Now you're contradicting yourself.
You say "take a tesseract, remove time, and you get a cube with width, height, and depth: space". Okay, let's continue this idea. Let's also remove depth and width, and we end up with a vertical segment. But you said it doesn't which dimensions we remove, so let's do something else now: let's take the tesseract and remove only width. We end up with a 2D universe plus a time dimension. Let's now remove height and depth. We end up with a time segment, do we not? Then, it seems we can start from an n-dimensional (for n > 1) shape, take away any one dimension, and end up with a valid n-1-dimensional shape. To me this seems like every dimension is equivalent to every other one, except in the name, and they're all independent from each other.

whereas is we have an object that doesn't exist in space, we know it doesn't move through time

Not true. Particles can be annihilated. Something that doesn't exist in space now might have existed in space previously. If something exists for any non-zero length of time then it does move through time, even if it doesn't currently exist in space.

Gravity is caused by mass which exists within space and moves through time.

No, mass exists and moves in spacetime. It has a trajectory in four dimensions.
https://en.wikipedia.org/wiki/World_line

Also, if space was as dependent on time as time was on space, would that mean the universe would disappear without time?

Yes. The word "universe" refers to spacetime: three spatial dimensions and a time dimension. If any of these is missing it's no longer the universe, but something different, because human beings can't live even in principle in such an environment.

However, space itself doesn't have any limitation like that, it's empty space after all, it doesn't need to move through time to exist.

Space doesn't move through time nor does time move through space. Those are meaningless sentences.

I think you're confusing colors as being physics. Colors have nothing to do with physics

The subjective experience of color is caused by electrochemical signals inside a living brain. How is that having nothing to do with physics?

If you watch the video I linked, it's explained pretty well. Color is an illusion and doesn't exist outside of our minds.

Look dude, I'm not stupid. I'm perfectly acquainted with the idea of qualia, and I'm saying it's bullshit. The [idea of color] inside your mind is as real as the electromagnetic radiation that was captured by your eyes. There's an electrochemical signal in your brain's circuitry that stores "red", analogously to how a computer uses electrical signals and the state of semiconductor circuits to store numbers to represent color intensities.
We can inspect the computer's memory, extract the numbers that represent color information, and interpret them to reconstruct an image.
Likewise, in principle we could inspect a person's brain, extract the visual information, and reconstruct whatever it is the person is seeing. Maybe you store "red" as 12 and I store it as 75 (I'm more inclined to believe most brains use basically the same method to represent and store visual information), but it doesn't matter. My point is that subjective experience is entirely caused by objective processes that can be measured.

[zapshe]

God's sakes. I've been copying and pasting all day my replies and ONLY this time I forget and it erased the whole thing.

What? But you just said, you can remove the oxygen without removing the air.

Hypothetically remove the oxygen from the air - like if we were to remove time from space. The point is that if you leave oxygen, you've left the room by default because the oxygen is fused with the air. Same with time and space, they're fused, so if you leave one you've by default left the other! I'm talking about somehow untangling them and removing one aspect, such as oxygen from the air, to show that one is not dependent on the other.

Yeah, but that's not what it means for time to end. If you take spacetime and remove time, the universe as we know it ceases to be, and to have ever been, completely and utterly. When I say that time ends I'm talking about reaching the end of file. You're talking about deleting the file.

If you mean when the universe ends and time and space cease to be, then who knows. If instead you mean time has reached the end somehow, then again, there's no reason to think space would also have to end also. It could be that the space will exist without time or will be at a standstill from the moment time stopped. Certainly the mass within space will not longer flow in time, any outsider not affected might think that the mass has disappeared because it has not followed them through time.

You say "take a tesseract, remove time, and you get a cube with width, height, and depth: space". Okay, let's continue this idea. Let's also remove depth and width, and we end up with a vertical segment. But you said it doesn't which dimensions we remove, so let's do something else now: let's take the tesseract and remove only width. We end up with a 2D universe plus a time dimension.

Within this universe, everything has to have 3 dimensions of space, height length width. Without them, you cannot exist in this universe as an object with mass, so you can't have 2d plus time. So if we have a 4d object, removing any dimension, including the time one, would result in a 3d object. If we have a 3d object and we remove height, length, or width, you'll end up with a 2d object with height and length regardless. Remove height and width or length will replace height. The object will always collapse into the dimensions its universe requires. So before you can have the time dimension, you need the preceding ones relating to space, since you simply cannot exist as a physical object in this universe without those dimensions.

Not true. Particles can be annihilated. Something that doesn't exist in space now might have existed in space previously. If something exists for any non-zero length of time then it does move through time, even if it doesn't currently exist in space.

If mass is annihilated then it is no longer in space or time after that. You can always look back and say it still exists within time since it use to exist, but at the same it also existed in space when it was existing in time. So what I meant by what I said was that when it no longer exists in space it no longer exists in time after that moment.

Yes. The word "universe" refers to spacetime: three spatial dimensions and a time dimension.

Definitely wouldn't be the universe as we know it, but would the universe and everything in it suddenly not exist at all?

Space doesn't move through time nor does time move through space.

Yes, it was just a side point, that space doesn't have to move through time to exist like mass does.

The subjective experience of color is caused by electrochemical signals inside a living brain. How is that having nothing to do with physics?

You know what I mean judging by your next paragraph. Inside the brain is physics, but there's no law of physics saying that all brains have to convert certain light frequencies to certain colors. Brains have genes which dictate that, and those can differ.

Look dude, I'm not stupid. I'm perfectly acquainted with the idea of qualia, and I'm saying it's bullshit.

Could have just said so, I thought you weren't understanding the concept. But I don't think we are disagreeing. Perhaps with the right technology and understanding, we could extract exactly what one's brain was perceiving and measure differences ourselves. But as of now, there's no way to know if our brains do perceive light the same because as you said, maybe i store red as 12 and another's brain stores it as 75. While I also think we probably experience colors similarly, there's no way to know in the present time with what we have. This is in part to do with the fact that, again, there's no law of physics dictating which color label our brains should assign to each light frequency, that's gene dictated and could be different between people. So again, I'm fairly certain we are agreeing here.

[keskiverto]

zapshe wrote:

Suppose you have a room full of Earth air and you remove the oxygen. There's still air in that room, it wasn't dependent on the oxygen. The air is still made up of other things. However, take away the air and you've gotten rid of oxygen.

https://en.wikipedia.org/wiki/Atmosphere_of_Earth

The atmosphere of Earth is the layer of gases, commonly known as air, ...

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases.

Ok, "air" is a common name for certain (varying) mixture of gases.

It is clear that removing all air removes all of its components, leaving vacuum.


"Air" on top of Mount Everest or in a submarine, whose carbon dioxide removal system has failed, has different mixture to the point that it is not suitable for breathing. The question is, can you refer to unbreathable mixture of gases with common name "air" or not?

[helios]

Without them, you cannot exist in this universe as an object with mass, so you can't have 2d plus time.

Elementary particles, such as electrons and photons, as far as we can tell have no dimensions. (To me it's maddening to think that ordinary objects are mostly empty. Things can touch only because of electric charge.)
Black holes may also have no dimensions; it seems they're singularities with infinite density, but we just don't know.
A two-dimensional space need not be empty.

But that aside, the reasoning "a 2D universe would be empty, there a 2D universe could not exist" is invalid. We have no idea have an empty universe would behave, because the only universe we know about is not empty.

So before you can have the time dimension, you need the preceding ones relating to space, since you simply cannot exist as a physical object in this universe without those dimensions.

Yeah, obviously a 2D universe would be unsuitable for humans. As would a universe without time. The question is about what a universe missing one of its dimensions would look like, and I see no reason why a universe with two spatial dimensions and time could not conceivably exist.

So what I meant by what I said was that when it no longer exists in space it no longer exists in time after that moment.

NO. It's no longer present in space, but if it ever existed then it exists in the time line. You can't use phrases like "no longer" when talking about the time line.
Like, suppose we're watching a movie, and a character dies at the 30 minute mark. The character will no longer appear in the 2D space of the movie (the picture), but he's still in the movie. We can go back to minute 20 and see him. The other characters at minute 40 might say "he's no longer here", but to us, as extra-temporal beings, the character's existence never changed. He exists in the time line of the movie, period.

there's no law of physics saying that all brains have to convert certain light frequencies to certain colors.

Ah, okay. Yes, that's certainly true.

"Air" on top of Mount Everest or in a submarine, whose carbon dioxide removal system has failed, has different mixture to the point that it is not suitable for breathing. The question is, can you refer to unbreathable mixture of gases with common name "air" or not?

Well, there's no hard definition for "air", so I suppose you can use the word to refer to anything you want, as long as you make it clear what you mean and use it consistently, without contradictions.

[zapshe]

Elementary particles, such as electrons and photons, as far as we can tell have no dimensions.

With things like electrons and photons are different. Photons are energy and have a different relationship. With Einstein's equation, E=mc^2, you could theoretically turn energy into mass and vice-versa. But energy isn't mass and so doesn't have to be a 3D object. Electrons, on the other hand, have mass according to many but then viewed as a mass-less point charge at times. There are a few calculated measurements out there for electrons, but who knows what's happening with volume. It would be logical to assume that if there's mass, then it has a volume, inconceivably small as it may be. I don't know enough about electrons and I keep finding contradictory information since electrons are really a mystery.

But that aside, the reasoning "a 2D universe would be empty, there a 2D universe could not exist" is invalid.

I wouldn't claim anything about a 2D universe. But the dimensions of the universe reflects the dimensions found for the objects within it.

NO. It's no longer present in space, but if it ever existed then it exists in the time line. You can't use phrases like "no longer" when talking about the time line.

Anytime mass exists in space it exists in time. Once it's not in space, it's no longer in time from that moment forward. If you go back on the timeline, then sure, it'll be there, but it'll also be in space. While I understand my language you quoted may not sit right, I'm sure you understand what I mean.

"Air" on top of Mount Everest or in a submarine, whose carbon dioxide removal system has failed, has different mixture to the point that it is not suitable for breathing. The question is, can you refer to unbreathable mixture of gases with common name "air" or not?

I don't think this is applicable to my analogy. But either way, if talking about Jupiter, you'd say, "The air in Jupiter can't sustain human life." Air is versatile I'd say.

[helios]

But the dimensions of the universe reflects the dimensions found for the objects within it.

But the universe is expanding without the objects within it (mainly galaxies) getting larger and without more matter being added in.

Anytime mass exists in space it exists in time. Once it's not in space, it's no longer in time

So what you're saying that if an object exists in space it exists in time, and if it doesn't exist in space it doesn't exist in time, correct? Then to you "X exists in space" and "X exists in time" are equivalent statements.
Why do you have two phrases that mean exactly the same thing?

[zapshe]

But the universe is expanding without the objects within it (mainly galaxies) getting larger and without more matter being added in.

Larger? If you're referring to volume, then that's because of expansion theorized to be happening from the start of the big bang. If you mean that it's gaining more mass, then that's definitely not true.

Also, I don't see what it has to do with the quote. If you're in a 3D universe, objects with mass will be 3 dimensional. That was my claim. In a 2D universe, I'd assume all objects to be 2 dimensional.

Why do you have two phrases that mean exactly the same thing?

Just to clarify. You were arguing my language, saying that I can't say "no longer" since it'll always exist somewhere in time. Was just saying that I mean "no longer" as in "from this point forward".

I barely remember what led us down these arguments xD

[N8MNAqkS]

No.

time is not an illusion. time is not physical, but it is a man made concept that allows us to differentiate between now, later, and before.

obviously there is a difference between past, present, and future. so there is your proof.

the concept of time is abstract but it is not an illusion. not unless you were taught that time was a physical thing.