Live data from Hacker News

What Is Spacetime, Really?

blog.stephenwolfram.com

11–20 of 122 posts

Re: What Is Spacetime, Really?

#11
post #9

Err... is Wolfram now taking credit for this idea, which began circulating back in 2009? http://www.nature.com/news/the-quantum-source-of-space-time-... Because I don't see his name in the citations...

I don't think that's the same idea, but he's got a chapter on the network universe idea in his book that was publshed in 2002.

Original credit for a discrete nature of the universe belongs to Democritus.

Re: What Is Spacetime, Really?

#12
post #11
post #9

Err... is Wolfram now taking credit for this idea, which began circulating back in 2009? http://www.nature.com/news/the-quantum-source-of-space-time-... Because I don't see his name in the citations...

I don't think that's the same idea, but he's got a chapter on the network universe idea in his book that was publshed in 2002. Original credit for a discrete nature of the universe belongs to Democritus.

I don't think that's the same idea

Hmm, upon a second read I think you're right.

One of the key distinguishing factors is the aforementioned Nature article actually cites hints of a real scientific theory based on established physics, while Wolfram's self-aggrandizing ramblings haven't actually led to any real discoveries... :)

Re: What Is Spacetime, Really?

#13
post #7

Maybe a physicist could help me out: the idea here of treating space as a simple discrete network, and particles just being emergent behavior sounds very interesting. But doesn't this violate Bell's Theorem, that no local hidden variables could completely explain quantum mechanics?

I am not a physicist, but Wolfram covers this. "Because there’s a theorem (Bell’s Theorem) that says that unless there’s instantaneous non-local propagation of information, no such “hidden variables” model can reproduce the quantum mechanical results that are observed experimentally." Wolfram's continues by saying he is allowing instantaneous non-local propogation because network nodes have no coordinates; coordinate…

Scott Aaronson argues that, based on what we know about quantum mechanics, Wolfram's "long-range thread" cannot reproduce special relativity and Bell inequality violations:

www.scottaaronson.com/papers/nks.ps

Re: What Is Spacetime, Really?

#15

Maybe a physicist could help me out: the idea here of treating space as a simple discrete network, and particles just being emergent behavior sounds very interesting. But doesn't this violate Bell's Theorem, that no local hidden variables could completely explain quantum mechanics?

IANAP either, but wasn't the hidden variable problem resolved by the pilot wave theory?

Re: What Is Spacetime, Really?

#17

I found this incredibly hard to read, due to Wolfram's constant need to self-aggrandize. The entire tone of the piece is, "I discovered this, then I discovered that". In reality, most of his "revelations" were discussed by others long before he arrived on set.

It's written in the first person, and he's describing the findings. How else should he have written it?

Wolfram is known for this. He's clearly a bright fellow but he is not even close to being the only or the first person to work on stuff like cellular automata, computational theories of physics, or complexity. He did not invent everything he claims to have invented and while he does footnote he's definitely not drawing attention to any of the others in the area.

It's tragic really. A New Kind of Science is full of brilliant ideas but the narcissism that drips from every page ruins it and probably prevents some of these ideas from getting the reception they deserve.

Re: What Is Spacetime, Really?

#18

In the beginning was a graph, more like diamond than graphite. Every node in this graph was tetravalent: connected by four edges to four other nodes. By a count of edges, the shortest path from any node back to itself was a loop six edges long. Every node belonged to twenty-four such loops, as well as forty-eight loops eight edges long, and four hundred eighty that were ten edges long. The edges had no length or shap…

Loved that book. Despite the cardboard characters :-)

Please tell me that last act made your think of Cellular Automata too!

Re: What Is Spacetime, Really?

#20
> OK, so one can derive Special Relativity from simple models based on networks. What about General Relativity—which, after all, is what we’re celebrating today? Here the news is very good too: subject to various assumptions, I managed in the late 1990s to derive Einstein’s Equations from the dynamics of networks.

What a crackpot. He links to his own book, which is a non-mathematical, non-technical book.

There is no mathematics in the linked material, so it's impossible to see whether he is correct, in fact it's impossible to see what he means at all!

Nobody has seen this mythical derivation he did in the 90s.

Amazing how someone brilliant who used to do real science fell into crackpottery like this.

Post reply on HN