
The brain's 7D sandcastles could be the key to consciousness (2017) - saadalem
https://www.newscientist.com/article/mg23531450-200-the-brains-7d-sandcastles-could-be-the-key-to-consciousness/
======
PH01
I struggled to find the meat in this article and a quick google of the terms
involved only really brings back the same article, which is almost 3 years old
now.

On top of that the story is a cookie cutter rewrite of every upcoming ML/math
technique which are always poised to provide some amazing insight into the
human mind.

A more honest title would be "algebraic topologists think algebraic topology
is great, academics who have employed algebraic topologists want it to be
great but don't really understand it".

Edit: for anyone looking for the actual meat this appears to be it:

Objective Morphological Classification of Neocortical Pyramidal Cells (2019)

[https://academic.oup.com/cercor/article/29/4/1719/5304727](https://academic.oup.com/cercor/article/29/4/1719/5304727)

~~~
Waterfall
You seem interested in this subject, I found this to be very interesting.
tl;dr they may wake people out of comas with psychedelics.
[https://www.frontiersin.org/articles/10.3389/fnhum.2014.0002...](https://www.frontiersin.org/articles/10.3389/fnhum.2014.00020/full)

------
krisoft
"They might even unravel the greatest mystery of them all: consciousness."

Don't get me wrong. Brains are interesting. Consciousness is a real puzzler.
But... the mass of the known universe is estimated to be about 10^53 kg. In
all that mass, there might be a few other mysteries here and there. Believing
that the "greatest mystery" is between our two ears feels a tad bit
egoistical.

~~~
HPsquared
"If a tree falls in the forest and nobody is around to hear it, does it make a
sound?"

Similar thing here. A mystery is a concept which can only occur within human
consciousness.

~~~
krisoft
You couldn't have illustrated my point nicer. Yes it makes a sound. There will
be vibrations in the air pressure propagating from the impact. If there are
birds around they might take a flight. The ground vibrations will create
ripples in the nearby pond which might distract a dragonfly enough that a frog
swallows it whole. I understand that I'm taking a Zen koan in the most literal
sense, but this the best way I can illuminate the ludicrousness of it. We are
not the centre of the everything. Things happen without us. Believing
otherwise is as I wrote egoistical, self-centered.

There is an unremarkable planet orbiting a regular star a thousand and two
light year away from us. On that planet there is a somewhat deer-like species
descendant from a prey animal. They are masters of mathematics, philosophy and
technology. Their cognition is so advanced that they would only politely smile
at the notion that "human consciousness" is the greatest mystery of all. One
of them between two ritual playfights took a dust bath on the meadow. It was
thinking about the atmosphere of gas giants, when he come up with a question.
There is not even a point in trying to explain to humans what the question
was. We don't have the capacity to comprehend it. That question was the
greatest mystery of all. Pity that they all went extinct before coming to
terms with their own inability to find their answer.

------
seesawtron
Too late to the thread but I will give it a shot.

First of all, the Blue Brain Project (equivalent of the US Human Brain
Project) has been widely criticised within the neuroscience community for its
failures to invest the funding appropriately [0,1] as well as failing to
produce their exaggerated claims of "brain on a computer", even 3 years after
this article was published.

Secondly, it is insanely hard to even map in all the connections between
neurons with their thousands of synapses. Imagine one neuron connects to
another 1000 neurons and a cubic millimeter of mouse cortex contains about
9×10^4 neurons. Even 1mm3 of cortex hasn't been mapped yet for a rodent
(mouse/rat) brain. Mapping the whole rodent brain will easily take another
decade [2].

Thirdly, even when you have mapped the complete brain, inferring states of
consiousness from it is a far fetched hypothesis and most neuroscients don't
even dare to go there because it is so absurd to talk about it from incomplete
simulation models.

Given the complexity of wiring of neurons and the sheer amount of specific
nature of this wiring, building simulation models assumes that the connections
between neurons are totally random which is an age old view which
computational neuroscientists are now starting to accept (except the BBP, for
now). Contrary to the BBP simulation models, this [3] model actually pays
attention to the observed wiring from past experiments and is the closest to
anything "realistic" but of course with several caveats.

[0] [https://www.scientificamerican.com/article/why-the-human-
bra...](https://www.scientificamerican.com/article/why-the-human-brain-
project-went-wrong-and-how-to-fix-it/)

[1] [https://www.theatlantic.com/science/archive/2019/07/ten-
year...](https://www.theatlantic.com/science/archive/2019/07/ten-years-human-
brain-project-simulation-markram-ted-talk/594493/)

[2]
[https://pubmed.ncbi.nlm.nih.gov/31055238/](https://pubmed.ncbi.nlm.nih.gov/31055238/)

[3]
[https://journals.plos.org/ploscompbiol/article?id=10.1371/jo...](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1006535#abstract1)

------
Waterfall
This doesn't have that much substance in the article. I hope that you haven't
heard of the entropic theory of the brain, its one of the most fascinating
theories and its very exciting!
[https://www.frontiersin.org/articles/10.3389/fnhum.2014.0002...](https://www.frontiersin.org/articles/10.3389/fnhum.2014.00020/full)
[https://mind-foundation.org/entropy-as-more-than-chaos/](https://mind-
foundation.org/entropy-as-more-than-chaos/)

------
uniqueid
I didn't understand the article at all, but it did make think about about how
many dimensions are required for humans to understand how objects in life
relate to each other.

I counted: a point, a line, a plane, a solid, a solid at a point in time, a
solid that might exist in some possible future, and a solid at a point in time
that might have existed if our past had been different.

That's all I could come up with (and I'm not even sure if the last one is a
dimension).

It's probably a coincidence (there's nothing crankier than numerology), but it
did make me happy that it adds up to seven.

~~~
echelon
> I counted: a point, a line, a plane, a solid, a solid at a point in time, a
> solid that might exist in some possible future, and a solid at a point in
> time that might have existed if our past had been different.

A solid in some parallel universe.

A solid in some fictitious parallel universe.

A solid in some non-cannon fictitious universe.

A solid thinking of another solid in some parallel universe derived by
combining one of more non-cannon offshoots of a particular fictitious universe
combined with our own but also exploring and deconstructing revisionist
history themes.

All of that, but also the main character is revising her schema to be in fifth
normal from.

That's kind of arbitrary, but I'm sure it regularly happens on
fanfictiction.net

Just because picturing geometry in more than three dimensions is hard, doesn't
mean we can't grapple with dimensionality or abstraction. We're pretty good at
it.

~~~
jerf
In the sense being used by the original article, those are not dimensions.
That is a very scify type of dimension, which has no known real-world
referent. The original list goes wrong at "a solid that might exist in some
possible future"; that is not a dimension. That is simply a solid with a time
value in the future, which is the same four dimensions as the preceding
example.

A dimension is an additional necessary number to characterize a system. Beyond
the location inside a point (0 numbers required), a line (1 number required),
a plane (2 numbers required), and a full 3D space (3 numbers required),
examples of real world entities that require more than three dimensions are:

A RGBA color value, which is four-dimensional.

The location and orientation of a rigid object; 6 dimensional. Three for the
location, three additional for the rotation.

The location, velocity, orientation, and spin rate of a rigid object: 12
dimensional. In addition to the previous six, three new ones needed for the
translational vector and three new ones needed for each spin axis rate.

Any arbitrary multiple of three: Any RGB image, where each pixel is three
dimensions each, one for R, G, and B. Images get to be high-dimensional spaces
very quickly.

High numbers of dimensions are hard to visualize, but they are completely
bereft of any "woo woo" value or any of the sort of mystery one might be
inclined to ponder on illegal substances. Bog-standard examples of such things
are encountered on a daily basis; the state of the display you are reading
this on is characterized by a several-million-component vector. That's how
"boring" and "normal" such things are. If you've got any of the woowoo in your
concept of "dimension", you don't understand dimensionality.

The bad news is that this may take away the vague fuzzy fun of pondering the
meaningless concept; the good news is that this opens you to much more
concrete and real, and still quite mysterious, fun of pondering real high
dimensionality spaces, which is a much richer and more interesting space that
has enough stuff to explore for the rest of your life, were you so inclined.
The "woo woo" scify concept is exhausted in five minutes, or perhaps a drug-
fueled trip. It may feel fun for a moment but it doesn't go anywhere.

~~~
uniqueid

       > That is simply a solid with a time value in 
       > the future, which is the same four dimensions 
       > as the preceding example.
    

My train of thought (not to say it's original) is: You can't move a solid
without another (a fifth) dimension (ie: time). You can't move the trail of
solids that exist in time without a second dimension of time (the sixth, if
we're counting all the way up from a 1D point). If you have two sequences of
events that are slightly different (side by side, ignoring that a "side" is a
4D side, I guess), that "timeline" which differs from the original is a
"possible universe".

~~~
jerf
The problem here is that you've got a subset/superset relationship reversed.
"Dimension" is simply the need to add a number to fully describe a system, as
I gave in the several examples. It is true that if there was some system of
parallel universes that a number identifying the universe could be necessary
to fully identify the location of an object. (Depending on the nature of the
multiple universes, it could even require more than one.) But "identifying
which universe something is in" is not the definition of "the fifth
dimension". It is simply a particular instance/subset of the general concept
of dimension, which happens to also be currently meaningless and without
referent. But even so, it manages to screw people up and provide significant
cognitive interference for the _real_ concept of dimensionality, which is, as
I said, much less "woo woo", which may be sort of disappointing, but also a
much richer concept that provides much more to explore, because it actually
has content to it.

You can also see the confusion in the miscounting of dimensions, because they
are not being thought of as simply numbers that identify a place/thing, but
some sort of ordered list of "concepts", where "things that don't exist yet"
are somehow in another "dimension". But as I said, you don't need another
"dimension" for that; it's just a time coordinate, which we already have, in
the future. This is the sort of thing that drives me to post this point.

It's a surprisingly popular viewpoint. There's a YouTube video that does this
sort of thing, which got very popular, and I don't even want to link to,
because it's a steaming pile of garbage, leaving viewers who watch it feeling
like they understand better when in fact they understand far worse. It's not
necessarily in the top ten list of "ideas that will prevent you from
understanding the world better" or anything, but it's certainly on that list.

~~~
uniqueid

        > But "identifying which universe something is in" 
        > is not the definition of "the fifth dimension".
    

Is there a difference?

Lets say we have a bunch of film strips, laid one on top of another, only each
frame represents an entire 3D universe, and each layer of a new film strip, at
the same point from the start, becomes less similar* as you move from layer to
layer. To identify where something is, you would refer to the delta (ie: of
the number of layers). That was what I was getting at.

*Hand-waving to ignore that in real life, each frame probably spawns multiple children, but only has one parent.

~~~
jerf
It is _a_ dimension, in your hypothetical example with no known real-world
correspondance. It is not _the_ fifth dimension.

"The" fifth dimension is a scifi concept, not a real one. Perfectly normal,
mundane reality contains numerous instances of much higher dimensionality.
Which of the subcolors of the pixels on your screen is "the" fifth dimension?

Dimensionality isn't "about" parallel universes. It is a very tiny, and really
quite useless, instance of the concept, which is full of useful and
interesting members that actually, you know, exist.

~~~
uniqueid

        > "The" fifth dimension is a scifi concept, 
        > not a real one. 
    

I'm confused now. How Is it possible for a dimension to "not be real" when a
dimension is just a way to relate multiple points together? Unless you run out
of points, can't you describe their relation using as many dimensions as you
need?

Maybe our communication is breaking down over the term "parallel universe". I
don't mean it as a sci-fi thing, I mean it as a Schrödinger's cat thing.

 _Without_ possible universes, we can't explain our intuition that an event
can have multiple outcomes. Why should _one_ of them happen, and not the
others? _With_ possible universes, there's no problem, because they _all_
happen. How would one describe the relation of _where_ they happen without a
dimension higher than time?

I don't mean a parallel universe as some fantastical place that we could
"visit" etc.

------
dr_dshiv
Isn't a another dimension simply another column in the table?

~~~
zitterbewegung
Yes, and if you have a set of tables (observations) you have a tensor.

------
plutonic
Perhaps I am missing something, but the use of dimensionality in this article
seems a bit overblown. The article says that a digraph meant to represent a
rat brain formed 8-cliques in response to some input data. You could represent
this 8-clique as a 7D structure ... but not necessarily. I am a bit worried
that a layperson will read the article and think that the human brain is
literally 7D in some actual way

~~~
ReactiveJelly
A lot of laypeople are already mixing up "dimension" with "universe".

"In an alternate dimension... thousands of different dimensions..."

------
dmix
> these transient structures, which appear and disappear like sandcastles on a
> beach

That's a good metaphor for building up elaborate programming concepts in your
brain then someone bothers you and it slips away. So you have to sit quietly
and build it back up (quicker this time).

------
cortic
>[what is..]consciousness

Isn't this an answered question? Consciousness is the sensation we get when we
point our ability to predict others actions back on itself. The inverse of
putting our-self in someone else's shoes. This was scientifically confirmed by
both the _decision delay_ experiments, as well as brain imagery that showed
the same circuitry activate whether you ask someone why _they_ did something;
or why _someone else_ did something.

That is not to say all the secrets of the brain have been understood or
uncovered, but this seems to be searching for a more feel-good answer to a
question that has largely been answered.

~~~
zxcmx
This still leaves the core problem - how does anyone (or anything) experience
anything at all?

~~~
cortic
The evidence suggests we don't feel anything at all, its more accurate to say
we rationalize ourselves with feelings and intentions than it is to say we
have feeling and intentions.

I've never actually tried to explain that before, having done so i understand
why we are appearing so desperate to find another answer.

------
archibaldJ
tldr: researchers build computational models of mice's brains then study the
models through methods of algebraic topology e.g. looking at artificial neural
cliques
([https://en.wikipedia.org/wiki/Neural_clique](https://en.wikipedia.org/wiki/Neural_clique))
up-closed i.e. at a level of detail unobtainable with an actual slice of brain
tissue, and measuring their dimensionalities

Here are the stuff the project published so far:
[https://www.epfl.ch/research/domains/bluebrain/blue-
brain/pu...](https://www.epfl.ch/research/domains/bluebrain/blue-
brain/publications/)

------
o_p
Wouldnt make more sense to try to describe the brain in computational science
terms rather than algebraic topology?

~~~
idclip
Dont we already attempt that as AI and NNs? Why not give math a chance too?

~~~
tsimionescu
NNs, other than being vaguely inspired by it, have nothing to do with the
brain or neurons. AI as it stands today also has essentially completely
abandoned any idea it may have once had of understanding any aspect of the
human brain or cognition, unfortunately.

Instead, NNs and AI are entirely focused on the external world and trying to
model it for strictly practical purposes (trying to predict aspects of it, in
general).

