Life is a braid in spacetime • Hacker News Board

Re: Life is a braid in spacetime

#31

Post by coldtea » Sat, Oct 03, 2015, 8:49 PM UTC

astrobe_ wrote: post #18

madaxe_again wrote: post #7

He does make the rather blithe assumption that mathematics is somehow real, and not an idiopathic artefact of our cognition, as much as the apparently respectively static and dynamic nature of space and time that he notes most posess. Perhaps mathematics is also a stubbornly persistent illusion. Me, I see the universe as information, and everything else flows from that. We are needles scratching out the tune from a h…

You can argue that Time is an illusion. You can argue that our intelligence allowed us to break free from the harsh laws of nature and evolution too soon, so we never acquired the necessary sensors and abilities. Maybe if we had to compete against multiple equally intelligent species, we would have acquired them. However, I think that using a "vision of Time as it really is" sensor correctly would require a far more…

>However Mathematics are different. It's not a perception. It even allowed us to discover things we could not perceive, and explore things we cannot perceive. It is independent from us and the universe.

You only say that as someone inside a universe with mathematics entangled with it. I don't think we can say anything about mathematics being "independent of the universe" just because we conceive them with our minds.

One could imagine another "universe" where even standard logic (A=A for starters) doesn't hold.

Re: Life is a braid in spacetime

#32

Post by Mz » Sat, Oct 03, 2015, 8:55 PM UTC

Of course, this begs the question of "How does this empower me to create a more glorious life?"

Perhaps the takeaway is that I am not a brain in a body moving through the world to do things. Instead, I am a mind and these patterns swirl around me and come and go and my awareness drives decision-making as to how to interact with these swirling, complex braids. Then, being the architect of the future is more like knowing where to put your finger.

Done right, this looks like magic.

Re: Life is a braid in spacetime

#33

Post by Ono-Sendai » Sat, Oct 03, 2015, 9:28 PM UTC

RivieraKid wrote: post #25

Ono-Sendai wrote: post #14

Earlier quoted context omitted.

My take on it is that special relativity provides no evidence that time is an extra dimension (like the spatial dimensions) in anything but a mathematical sense. General relativity however has quite a lot of effects that mingle together space and time in various ways, so I'm still thinking about that one.

> no evidence that time is an extra dimension (like the spatial dimensions) in anything but a mathematical sense What do you mean by time being an extra dimension in non-mathematical sense? Dimensions and space are mathematical concepts.

Some people think that time is physically similar to space, e.g. that their is something 'out there', physically existing, which we call space-time.

Re: Life is a braid in spacetime

#34

Post by api » Sat, Oct 03, 2015, 10:31 PM UTC

dweinus wrote: post #23

api wrote: post #16

Earlier quoted context omitted.

A big source of confusion is dimension as mathematical vector element vs spatial dimension. These are different concepts. Still it is interesting that x, y, and z seem identical while t is intrinsically unidirectional. Why?

Not a physicist -> My assumption is that this is because x,y,z are just constructs to model physical space. They don't exist and we could just as well describe space with cartisian coordinates or some other system where the dimensions would not be isometric. Meanwhile, as you point out, t as a vector is also itself a convenient model for something, not an actual dimension.

Hmm... if t is also then not a Cartesian dimension, it makes me wonder if the whole Cartesian model isn't a bad model of fundamental reality. Maybe it's just a mathematical shortcut.

Re: Life is a braid in spacetime

#35

Post by musicaldope » Sat, Oct 03, 2015, 10:33 PM UTC

vortico wrote: post #29

I'm studying topological quantum computation, and in this field one considers particles confined to 2 dimensions called anyons. As a collection of anyons move around, the paths they take in spacetime "tangle together" and have the structure of an element of the braid group ( https://en.wikipedia.org/wiki/Braid_group ). Two anyons cannot exist at the same place and time, and thus their world lines cannot pass through…

Any in-depth and technical sources you'd recommend?

Re: Life is a braid in spacetime

#36

Post by drostie » Sat, Oct 03, 2015, 11:10 PM UTC

tmsam wrote: post #27

drostie wrote: post #20

Speaking as a physicist, I in general like this article, however there is a nasty technical point to make, which is that if you actually use distance units to measure time, we look like the "inanimate object, simple pattern", not the "living object, complex pattern." Moreover the "death, disintegration" slide is not going to be what you look like unless you happened to be in the vicinity of a bomb at your death. Stil…

As a trained, but non-practicing, physicist, I would like you to elaborate about your first paragraph. I am used to using units where c=1, I think that is what you are referencing: a "meter" of time is the time it takes light to go a meter (which is to say, a very small amount of time) and so a second is 3x10^8 m. I don't see how this changes the pattern we would make in spacetime. If we assume no one ever moves (a n…

Because the timescales that you're "moving" on are very long from a relativistic perspective. If we localize you in spacetime you're maybe a meter long in one direction, two meters in another, half a meter in a third, and... 30,000 km in the fourth. If we look at you on the nanosecond timescale that you need to see time as "meters" we find that except for, say, electrons' worldlines about the nuclei, your worldlines are very much all parallel to each other.

Re: Life is a braid in spacetime

#37

Post by foma » Sun, Oct 04, 2015, 1:59 AM UTC

A wonderful picture of space and time. My religion fits very well with the concepts of fate and destiny suggested by this picture. Our benevolent creator has for us woven a fantastically complex braid and I am humbled by the chance to take it in. Busy busy busy

Re: Life is a braid in spacetime

#38

Post by foobarian » Sun, Oct 04, 2015, 3:07 AM UTC

api wrote: post #16

whatshisface wrote: post #15

Earlier quoted context omitted.

Time can be a dimension and still be treated differently. In fact, in special relativity, it is. When calculating the spacetime "distance" between two events, we use something that looks like the Pythagorean theorem, but we must always make sure to put a different sign in front of time than we do space. (If we sum the squares of space, we must subtract the square of time) (see: minkowski metric, really any metric) An…

A big source of confusion is dimension as mathematical vector element vs spatial dimension. These are different concepts. Still it is interesting that x, y, and z seem identical while t is intrinsically unidirectional. Why?

It helps me think of it as the iteration number in simulations. The state of the world at every iteration i+1 is a function of the state at i. Therefore it's impossible for a phenomenon in the simulation to alter the previous states.

Re: Life is a braid in spacetime

#39

Post by vortico » Sun, Oct 04, 2015, 6:00 AM UTC

musicaldope wrote: post #35

vortico wrote: post #29

I'm studying topological quantum computation, and in this field one considers particles confined to 2 dimensions called anyons. As a collection of anyons move around, the paths they take in spacetime "tangle together" and have the structure of an element of the braid group ( https://en.wikipedia.org/wiki/Braid_group ). Two anyons cannot exist at the same place and time, and thus their world lines cannot pass through…

Any in-depth and technical sources you'd recommend?

Alexei Kitaev's original paper in 1997 which started the field, and the overview by Freedman, Kitaev, et at. 2008 are a good start.

Re: Life is a braid in spacetime

#40

Post by Kristine1975 » Sun, Oct 04, 2015, 9:04 AM UTC

stuxnet79 wrote: post #21

Kristine1975 wrote: post #13

How long until Greg Egan writes a novel based on this concept? It should be right up his alley.

Interesting that everyone automatically defaults to Greg Egan when thinking of hard mind-bending sci-fi that explores concepts like these. I don't even remember how I got into Greg Egan, but do you have any other favorite authors who play with concepts like these? In my head, Greg Egan is filed under the "Math-Fi" directory, as that's what I generally associate him with but he's very well versed in pretty much everyt…

>but do you have any other favorite authors who play with concepts like these?

Maybe Philip K Dick, although his books are not exactly hard science fiction. But they explore the nature of reality in often mind-bending ways.