Thoughts on Hawking's No-Boundary Proposal of Universe

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Discussion Overview

The discussion revolves around Stephen Hawking's no-boundary proposal of the universe, exploring its implications, particularly regarding the concepts of imaginary time and the relationship between mathematics and physics. Participants engage with theoretical aspects, mathematical interpretations, and philosophical implications of the proposal.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants describe the no-boundary proposal as a Wick's rotation of the universe, suggesting it makes sense in a certain context.
  • There is a discussion about the use of imaginary time, with one participant noting that imaginary time is represented by real numbers, while real time is represented by imaginary numbers.
  • One participant posits that the universe can be viewed as a 4D sphere and questions which spatial dimension undergoes Wick rotation, linking this to the nature of time.
  • Criticism is raised regarding the use of imaginary time, with some suggesting it may be a mathematical convenience rather than a physical reality.
  • Another participant argues that there is no distinction between physics and mathematics, asserting that Wick rotation has fundamental physical meaning beyond mere mathematical trickery.
  • Questions are posed about whether Hawking's proposal implies that imaginary time is a real aspect of the universe or if it serves only as a mathematical model for predictions.
  • One participant introduces Max Tegmark's Mathematical Universe Hypothesis (MUH), suggesting that the no-boundary proposal aligns with this hypothesis, which posits that mathematics is reality itself.
  • Another participant questions the scientific support for MUH, suggesting it may lean more towards metaphysical theory.
  • One participant claims that MUH is falsifiable, proposing that a theory of everything (TOE) could be expressed purely in mathematical terms without linguistic explanations.

Areas of Agreement / Disagreement

Participants express a variety of views on the implications of imaginary time and the relationship between mathematics and physics. There is no consensus on whether the no-boundary proposal describes reality or serves merely as a mathematical model. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants express uncertainty regarding the implications of imaginary time and the nature of Wick rotation. There are also unresolved questions about the relationship between mathematics and physical reality, particularly in the context of MUH.

MrQG
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What are everyone's thoughts on the (Hawking's) no-boundary proposal of the universe? Thank you in advance.
 
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As I understand, it is Wick's rotation of the whole Universe.
It makes sense to me.
 
And what about its use of imaginary time?
 
The funny thing is imaginary time is represented by real numbers while real time is represented by imaginary numbers.
Our world is 4D sphere with metric ++++, Wick rotation of one of the spatial dimensions (which one? I don't understand) makes it infinitely expanding and with metric +++-
So our 'real' time we observe is imaginary (because it has "i" multiplier, - metric). Our time is a reflection of what Hawking calls "imaginary" time, but mathematically that time is real one because it is a part of ++++ metric.
 
I've heard some people criticize the proposal claiming that the use of imaginary time is simply for mathematical convenience. What do you think? I appreciate your thoughts.
 
I don't think there is a difference between physics and mathematics.
Also, it explains for example why our metrics is +++-,
and why Schrödinger equation is Wick rotation of fundamental solution of heat equation.
so it explains why Wicks roation is not just mathematics trick but has deep and fundamental physical meaning.
 
So, would you say that Hawking is actually postulating that "imaginary" time is something real, as in, actually there? Is he saying that this proposal actually describes reality or is it merely a mathematical model meant to make accurate predictions? Does he somehow "refuse" to convert back "real" time? Thanks.
 
I don't know if Hawking accepts, implicitly or explictly, Max Tegmark's Mathematical Universe Hypotesis (MUH). But IMHO the way of thinking you need to come to the idea of No boundary proposal requires MUH. Based on MUH, your question

this proposal actually describes reality or is it merely a mathematical model meant to make accurate predictions?

does not make any sense, because MUH postulates that mathematics does not describe the reality, it is reality
 
That's an interesting hypothesis. Does it have much support? However, it sounds more like a metaphysical theory than a scientific one.
 
  • #10
The proof of MUH it simple: it predicts that one will be able to express TOE in a form of mathematical equations, without any "word baggage". You won't need words like "t stands for time" etc. Just pure formulas. So MUH is falsifiable.
 

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