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If it is true for matter, and the universe is the sum total of all existent matter, why wouldn't it be true for the universe? Put another way: "Expands into so

If it is true for matter, and the universe is the sum total of all existent matter, why wouldn't it be true for the universe? Put another way: "Expands into something else" is what "expands" means.

ThomPete 17y ago
Words don't dictate reality. And words sure don't represent reality. The expanding universe theory is an attempt to visualize what is going on, not to actually describe what is really going on. Language is a simplification of reality. They create linear narratives (expanding from something smaller to something bigger) But just as time probably isn't what we think it is, these narratives aren't anything but descriptors of experienced phenomena. Just as when Dawkins talks about the selfish gene. He isn't saying that they are really selfish (they don't have agency) he say they behave as if they are selfish. There is absolutely nothing that dictates that we need to be able to express in language what is going on, case in point quantum physics where we have non locality. The expanding universe theory makes sense because the metaphors used to describe it take our perspective into consideration. But in reality there isn't necessarily any expansion taking place. In physical reality yes, but that is not all of reality.
- samd 17y ago
  "Everything is vague to a degree you do not realize till you have tried to make it precise." - Bertrand Russell
stcredzero 17y ago
When the balloon expands, its two dimensional surface are increases because the balloon is expanding into the 3rd dimension. Why can't a universe of n dimensions simply expand into the n+1 dimension? Or, put in a better way - the universe humans can perceive is expanding, without expanding into anything else we can perceive.
- JoeAltmaier 17y ago
  Exactly
- retube 17y ago
  You're reading too much into the analogy. It's merely to help understand how a 3D space can expand without having a center, and nothing else.
  - stcredzero 17y ago
    I just explained the workings of the analogy. I think you're parroting those words without completely understanding my comment or the words themselves. (Note, if all matter is n-dimensional, then expansion of the n-dimension space into dimension n+1 wouldn't be expansion of the Universe into anything. It would be the expansion of an n-dimension subset into an n+1 dimension universe.)
- goodside 17y ago
  Because positing the existence of an n+1 dimension complicates the theoretical model without adding to its predictive power. Curvature and expansion can be defined perfectly well using intrinsic measures within n dimensions, without positing another. Further, the n-dimensional manifold might curve in ways that cannot be embedded into n+1 dimensions. For example, a Klein bottle is a logically possible shape of a 2D universe that cannot be embedded into a 3D universe without colliding with itself. Now, if this happens you might say, "Aha! But a Klein bottle can indeed exist embedded in 4D. So perhaps our universe is not in n+1 dimensions, but n+2." But how far does this continue? Adding dimensions every time you find something new out about the curvature of space is like adding epicycles to the geocentric model. You don't need an infinite supply of dimensions to embed the universe in, since everything you know about it can be described without reference to any of these unobservable dimensions that you might suppose exist.
Herring 17y ago
>If it is true for matter, and the universe is the sum total of all existent matter, why wouldn't it be true for the universe? http://en.wikipedia.org/wiki/Fallacy_of_composition http://en.wikipedia.org/wiki/Fallacy_of_composition http://www.logicalfallacies.info/relevance/composition/ http://www.logicalfallacies.info/relevance/composition/

If it is true for matter, and the universe is the sum total of all existent matter, why wouldn't it be true for the universe? Put another way: "Expands into something else" is what "expands" means.

ThomPete 17y ago

Words don't dictate reality. And words sure don't represent reality. The expanding universe theory is an attempt to visualize what is going on, not to actually describe what is really going on. Language is a simplification of reality. They create linear narratives (expanding from something smaller to something bigger) But just as time probably isn't what we think it is, these narratives aren't anything but descriptors of experienced phenomena. Just as when Dawkins talks about the selfish gene. He isn't saying that they are really selfish (they don't have agency) he say they behave as if they are selfish. There is absolutely nothing that dictates that we need to be able to express in language what is going on, case in point quantum physics where we have non locality. The expanding universe theory makes sense because the metaphors used to describe it take our perspective into consideration. But in reality there isn't necessarily any expansion taking place. In physical reality yes, but that is not all of reality.

samd 17y ago
"Everything is vague to a degree you do not realize till you have tried to make it precise." - Bertrand Russell

stcredzero 17y ago

When the balloon expands, its two dimensional surface are increases because the balloon is expanding into the 3rd dimension. Why can't a universe of n dimensions simply expand into the n+1 dimension? Or, put in a better way - the universe humans can perceive is expanding, without expanding into anything else we can perceive.

JoeAltmaier 17y ago
Exactly
retube 17y ago
You're reading too much into the analogy. It's merely to help understand how a 3D space can expand without having a center, and nothing else.
- stcredzero 17y ago
  I just explained the workings of the analogy. I think you're parroting those words without completely understanding my comment or the words themselves. (Note, if all matter is n-dimensional, then expansion of the n-dimension space into dimension n+1 wouldn't be expansion of the Universe into anything. It would be the expansion of an n-dimension subset into an n+1 dimension universe.)
goodside 17y ago
Because positing the existence of an n+1 dimension complicates the theoretical model without adding to its predictive power. Curvature and expansion can be defined perfectly well using intrinsic measures within n dimensions, without positing another. Further, the n-dimensional manifold might curve in ways that cannot be embedded into n+1 dimensions. For example, a Klein bottle is a logically possible shape of a 2D universe that cannot be embedded into a 3D universe without colliding with itself. Now, if this happens you might say, "Aha! But a Klein bottle can indeed exist embedded in 4D. So perhaps our universe is not in n+1 dimensions, but n+2." But how far does this continue? Adding dimensions every time you find something new out about the curvature of space is like adding epicycles to the geocentric model. You don't need an infinite supply of dimensions to embed the universe in, since everything you know about it can be described without reference to any of these unobservable dimensions that you might suppose exist.

Herring 17y ago

>If it is true for matter, and the universe is the sum total of all existent matter, why wouldn't it be true for the universe? http://en.wikipedia.org/wiki/Fallacy_of_composition http://en.wikipedia.org/wiki/Fallacy_of_composition http://www.logicalfallacies.info/relevance/composition/ http://www.logicalfallacies.info/relevance/composition/