Jul 27, 2016 02:25 AM
(This post was last modified: Jul 29, 2016 06:04 AM by C C.)
The Debate Over Time's Place in the Universe
http://www.theatlantic.com/science/archi...se/492464/
EXCERPT: Physicists can’t agree on whether the flow of future to past is real or a mental construct. [...] In the face of these competing models, many thinkers seem to have stopped worrying and learned to love (or at least tolerate) the block universe.
Perhaps the strongest statement made at the conference in favor of the block universe’s compatibility with everyday experience came from the philosopher Jenann Ismael of the University of Arizona. The way Ismael sees it, the block universe, properly understood, holds within it the explanation for our experience of time’s apparent passage. A careful look at conventional physics, supplemented by what we’ve learned in recent decades from cognitive science and psychology, can recover “the flow, the whoosh, of experience,” she said. In this view, time is not an illusion—in fact, we experience it directly. She cited studies that show that each moment we experience represents a finite interval of time. In other words, we don’t infer the flow of time; it’s part of the experience itself. The challenge, she said, is to frame this first-person experience within the static block offered by physics—to examine “how the world looks from the evolving frame of reference of an embedded perceiver” whose history is represented by a curve within the space-time of the block universe.
Ismael’s presentation drew a mixed response. Carroll said he agreed with everything she had said; Elitzur said he “wanted to scream” during her talk. (He later clarified: “If I bang my head against the wall, it’s because I hate the future.”) An objection voiced many times during the conference was that the block universe seems to imply, in some important way, that the future already exists, yet statements about, say, next Thursday’s weather are neither true nor false. For some, this seems like an insurmountable problem with the block-universe view. Ismael had heard these objections many times before. Future events exist, she said, they just don’t exist now. “The block universe is not a changing picture,” she said.“It’s a picture of change.” Things happen when they happen. “This is a moment—and I know everybody here is going to hate this—but physics could do with some philosophy,” she said. “There’s a long history of discussion about the truth-values of future contingent statements—and it really has nothing to do with the experience of time.” And for those who wanted to read more? “I recommend Aristotle,” she said....
Dimensional reduction: The key to physics greatest mystery?
http://www.forbes.com/sites/startswithab...t-mystery/
EXCERPT: What if the Universe – and fundamentally, space itself – were like a pile of laundry?
Have one.
See this laundry pile? Looks just like our universe.
No?
Here, have another.
See it now? It’s got three dimensions and all.
But look again.
The shirts and towels? They’re not truly three-dimensional. They’re really crinkled and interlocked two-dimensional surfaces.
Wait.
These surfaces aren’t real, after all. It’s really one-dimensional yarn, knotted up tightly.
You ok?
Have another.
I see it clearly now. It’s everything at once, one-two-three dimensional. It just depends on how closely you look at it.
Amazing, don’t you think? What if our universe was just like that?
It doesn’t sound like a sober thought, but it’s got math behind it, so physicists think there might be something to it. Indeed the math has piled up lately. They call it “dimensional reduction,” the idea that space on short distances has fewer than three dimensions – and it might help physicists to quantize gravity. We’ve gotten used to space with additional dimensions, rolled up so small (or compactified) that we can’t observe them. But how do you get rid of dimensions instead? To understand how it works we first have clarify what we mean by “dimension....”
http://www.theatlantic.com/science/archi...se/492464/
EXCERPT: Physicists can’t agree on whether the flow of future to past is real or a mental construct. [...] In the face of these competing models, many thinkers seem to have stopped worrying and learned to love (or at least tolerate) the block universe.
Perhaps the strongest statement made at the conference in favor of the block universe’s compatibility with everyday experience came from the philosopher Jenann Ismael of the University of Arizona. The way Ismael sees it, the block universe, properly understood, holds within it the explanation for our experience of time’s apparent passage. A careful look at conventional physics, supplemented by what we’ve learned in recent decades from cognitive science and psychology, can recover “the flow, the whoosh, of experience,” she said. In this view, time is not an illusion—in fact, we experience it directly. She cited studies that show that each moment we experience represents a finite interval of time. In other words, we don’t infer the flow of time; it’s part of the experience itself. The challenge, she said, is to frame this first-person experience within the static block offered by physics—to examine “how the world looks from the evolving frame of reference of an embedded perceiver” whose history is represented by a curve within the space-time of the block universe.
Ismael’s presentation drew a mixed response. Carroll said he agreed with everything she had said; Elitzur said he “wanted to scream” during her talk. (He later clarified: “If I bang my head against the wall, it’s because I hate the future.”) An objection voiced many times during the conference was that the block universe seems to imply, in some important way, that the future already exists, yet statements about, say, next Thursday’s weather are neither true nor false. For some, this seems like an insurmountable problem with the block-universe view. Ismael had heard these objections many times before. Future events exist, she said, they just don’t exist now. “The block universe is not a changing picture,” she said.“It’s a picture of change.” Things happen when they happen. “This is a moment—and I know everybody here is going to hate this—but physics could do with some philosophy,” she said. “There’s a long history of discussion about the truth-values of future contingent statements—and it really has nothing to do with the experience of time.” And for those who wanted to read more? “I recommend Aristotle,” she said....
Dimensional reduction: The key to physics greatest mystery?
http://www.forbes.com/sites/startswithab...t-mystery/
EXCERPT: What if the Universe – and fundamentally, space itself – were like a pile of laundry?
Have one.
See this laundry pile? Looks just like our universe.
No?
Here, have another.
See it now? It’s got three dimensions and all.
But look again.
The shirts and towels? They’re not truly three-dimensional. They’re really crinkled and interlocked two-dimensional surfaces.
Wait.
These surfaces aren’t real, after all. It’s really one-dimensional yarn, knotted up tightly.
You ok?
Have another.
I see it clearly now. It’s everything at once, one-two-three dimensional. It just depends on how closely you look at it.
Amazing, don’t you think? What if our universe was just like that?
It doesn’t sound like a sober thought, but it’s got math behind it, so physicists think there might be something to it. Indeed the math has piled up lately. They call it “dimensional reduction,” the idea that space on short distances has fewer than three dimensions – and it might help physicists to quantize gravity. We’ve gotten used to space with additional dimensions, rolled up so small (or compactified) that we can’t observe them. But how do you get rid of dimensions instead? To understand how it works we first have clarify what we mean by “dimension....”