
Life is a braid in spacetime - edem
http://nautil.us/issue/29/scaling/life-is-a-braid-in-spacetime-rp
======
madaxe_again
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 hyperdimensional record. Our
mathematical laws may well be encoded within that information, or are
representative of symmetry within it, which is also reflected on the
structures and strictures of our minds, but I see mathematics as effect rather
than cause - not that there's really such a thing as causality, either, if you
stop thinking of "the arrow of time" as being a thing other than how we
experience spacetime. Causality is as human an invention as sunrise.

Then again, I'm assuming that information can exist.

Perhaps it's turtles^W simulations all the way down.

~~~
astrobe_
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 complex and energy-hungry brain, so it's
probably not "worth it" from an evolutionary perspective. Or maybe it's out of
reach of carbon-based organisms.

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. And if you still want to
throw away Mathematics, you'll also have to throw away logic, which is kind of
an issue. The only thing one could seriously argue, is that something better
than Mathematics exists, like General Relatively is "better" than Newtonian
mechanics. But maybe that is out of our reach, too.

Meanwhile, repeat after me: I believe in _modus ponens_ , set theory and
monads.

~~~
coldtea
> _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.

------
dahart
The idea of "spacetime" makes a fun narrative, fun thought experiments, and
interesting ways to graph and visualize events.

But many physicists wish that popularizing this concept would stop and go
away, because it is misleading. There is both evidence and theoretical work
demonstrating that time, unlike the spatial dimensions, is not a choice when
it comes to direction of travel, and never will be.

The definition of time as a numerical order of change in space is replacing
the 106-year-old concept of time as a physical dimension in which change
runs,” Sorli said. “We consider time being only a mathematical quantity of
change that we measure with clocks. This is in accord with a Gödel view of
time. By 1949, Gödel had produced a remarkable proof: 'In any universe
described by the theory of relativity, time cannot exist.' Our research
confirms Gödel's vision: time is not a physical dimension of space through
which one could travel into the past or future.”

[http://phys.org/news/2012-04-physicists-abolish-fourth-
dimen...](http://phys.org/news/2012-04-physicists-abolish-fourth-dimension-
space.html)

Edit: previous thread on HN re this article:
[https://news.ycombinator.com/item?id=3842734](https://news.ycombinator.com/item?id=3842734)

Sounds like some think this phys.org article is BS. I don't know, I am not a
physicist. But I have been wondering for many years whether it makes sense to
treat time as a dimension. I assumed it made sense in relativity study, and
has been mistranslated in popular science culture as a thing that somehow
opens up the option of time travel.

~~~
whatshisface
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)

Another point of interest would be the matrix representation of the Lorentz
transformation (the way to go from one reference frame to another). The matrix
"mixes" the values of the time coordinate with the space coordinates, and the
space coordinates with each other, but time is mixed _differently._ (This is a
nice one to bring up because its clear if you just look at the matrix.)

This is very significant for people wondering about time's status as a
dimension. It is _emphatically not_ the same kind of dimension as space, even
if we choose to represent it as a component of the position vector.

~~~
api
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?

~~~
dweinus
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.

~~~
api
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.

------
lifeisstillgood
Simply beautiful thoughts.

I love the idea that the atoms of our bodies are replaced over the years -
that no part of me today was a part of me in my twenties - and this concept,
the braid in spacetime, puts it more eloquently and more bravely than I could
think.

It's great to be able to take words written by some guy on another part of the
world and have them rearrange my brain and my thoughts - this is beautiful.

~~~
3pt14159
Actually there are parts of you that were parts of you in your twenties. Some
of the brain cells, some of your heart cells, and if you are a woman, your
eggs.

Unless you are talking about how matter pops in and out of a apparent reality,
in which case we're going too far down for me.

~~~
ThomPete
If you are left only with some of your brain cells and some of your heart
cells and if your are a woman your egs, are you still an aware human being?

You and other people are missing the point of the perspective and on top of
that you are even admitting that even what you claim is constant isn't really
when it comes down to it (matter popping in an out).

The insight is of course that things are always in flux and that they are much
less "solid" than they might look.

You are obviously free to dismiss this as interesting but I find it hard to
swallow this kind of "the hole in the cheese" comments. It's everything thats
wrong with critical thinking.

~~~
maddayou
You wrote an interesting comment, shure around the cheese-holes there is
"taste" but let me ask:

Do You Braid For Me ? Do You Braid For Yourself Too ;)

Meanwhile: [http://i.imgur.com/m1x2MtU.png](http://i.imgur.com/m1x2MtU.png)

------
drostie
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.

Still the question of how we reconcile our sense of ourselves as speech-act-
performing free-will-having conscious-feeling observers embedded in a changing
world, with a relativistic perspective which says "there probably isn't one
constantly-updating 'present' because a 'present' can be any hyperplane
between two light cones, and therefore we can never have any physical basis to
choose one as the correct one," is one of many really important philosophical
questions that I think are important, though not really my domain.

~~~
tmsam
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 nice physics-y approximation), but the
particles that make them up do, so I don't see why we wouldn't look like the
middle pattern while alive. Then after death, the disintegration is
exaggerated, but again, it seems more-or-less right to me. What am I missing?

~~~
drostie
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.

------
vortico
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](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 each other. This is useful, since any sort of physical
error in the system will preserve its braid structure, saving the need for
quantum error correction.

This article is mostly fluff (except for the two diagrams, whose captions
contain more content than the article), but I'm sure it makes an interesting
read for those wishing for light philosophical thought rather than deep and
novel technical concepts.

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

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

------
Kristine1975
How long until Greg Egan writes a novel based on this concept? It should be
right up his alley.

~~~
stuxnet79
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
everything (Biology, Physics, etc).

~~~
Kristine1975
>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.

------
Mz
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.

------
mbfg
I'll buy that your spacetime braids disintegrate at death altho i'd think they
be more like the parallel braids of a stone, not like those shown
helicoptering out as in the picture.

But as for birth, clearly your start branches off of the braids of your
mother. and so start immensely tangled to begin with.

------
foma
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

------
sgt101
Physics is a description, maths is the best method of describing things in
physics, but when things head to infinity it's a sign that the descriptive
system is breaking down.

Time real, neither the past nor future exist.

------
Wayin
This is purely commercial balony

