[Warning, what I am going to random idea about is ghostly... (nope, not the QFT ghostly)]

Let's suppose A is in a house with two rooms

In one room, A felt the air has a very dense feeling, but only A can feel it

@Semiclassical ugh, heat flow in an annulus now

A has a friend, B, who when is present in the room, A felt the air is less dense

these homeworks are growing exponentially in time it takes to complete

Now when B left the room, A felt the air is dense again.

The problem: We cannot tell experimentally whether A's feeling is due to his minds playing tricks on him or there is some ghosty presence which only felt by A, but is nevertheless scared away by B

Therefore, let's modify the scenario as follows:

Suppose you receive a machine from your friend which does one thing: It gives out flashing green light at periodic intervals

Now, you have a sensor mounted on a wheel:

The sensor will move closer to the machine until the frequency of flashing (correcting for delay) changes

and after that, it will just stop in place

So, we have an interesting system that models a notion of subjective experience:

The machine that is given to you is said to made flashes based on sensing some kind of stimulus (e.g. very low frequency sound that typical machines don't pick up because they are not designed to detect those low frequencies)

However, you have no way to check whether this is the case (As opening up the machine does not give much information and you are not good at circuits) thus you can only trust the machine is working as intended

Now, the sensor with the robotic wheel is actually made of a special material that reflect the low frequency sound waves

and therefore if it move closer to the machine, the machine flashes less frequent because the low frequency sound is less

I'm starting to suspect that ACM is the real cosmic entity

However, based on just looking at this system of machine and sensor and behaviour alone, you can only conclude one thing:

Shog pales in comparison to ACMs omnipresence

@Phase why?

There's a machine, which flashes periodically, and with its flashing frequency depends on how far away the sensor is, nothing more

ACM exists eternally answering seemingly any question like a mysterious sage

uh

and therefore, this model suggests that since we cannot even tell what an arbitrary machine is responding to, or why it is having that kind of behaviour, what is the hope of experimentally detecting ghosts and the paranormal?

@Secret I don't think that's..

Science is the study of nature

Paranatural / supernatural are not subsets of nature

By definition the people claim they transcend physical laws

I am trying to use some machine analogy to describe how hard it is in general to verify an ancedote, which is a common way to record events for purported paranormal communities or religious communities etc.

in some sense, unless you know how the machine works, you cannot understand what the machine is perceiving about the world, and hence what it is recording and responding

More generally, it is just as hard to understand the world in the eyes of a machine as in the eyes of a bee

Subjective experience, in some sense, is private, only you can perceive it and you cannot share it

Call me jaded but I can't really entertain that discussion in my head, my brain just screams at me that science has it's limits, and finding out whether supernatural things do or don't exist is something that no scientific model will be able to do

@JohnRennie Can you please run a distcc on one of your servers for me?

and same for what a machine 'sees' the world as

That's a paragraph from the philosopher F.H. Bradley which TS Eliot quotes in his Notes for "The Waste Land"

@Semiclassical Have you ever experienced typos on arXiv dates?

Science has its limits, but it is interesting to understand how and why the limits are there. Philosophy does a good job on that

This paper is allegedly from 2006 but it references stuff from 2015.

not that come to mind

@BernardoMeurer My main server actually isn't any more powerful than your laptop. It uses a Xeon E3-1220.

...huh

weird

see call me a philistine or a villain but I dislike the whole "philosophy" side to Physics

@Semiclassical it was updated in 2016, but the 2006 version doesn't make sense

it's missing like half of the stuff

huh

link?

arxiv.org/abs/math/0608795

The inability to see even a machine's private world in general has real significance in AI researches: There are discussions going on how to make their black box more understandable to humans so that we knew whether it has actually done the task properly, such as whether a neuro network have identify its targets correctly

@Semiclassical whoa you can access the 2006 version

it's completely different

@JohnRennie I can't take these kernel compilation times anymore

he took out the pictures in the 2016 version :/

I am dying

Also it is literally boiling my scrotum

Sounds uncomfortable

@BernardoMeurer don't use the laptop while naked :-)

I'm sorta amused that the bibliography (for the 2006 version, at least) includes two papers "in preparation" from the same author

Maybe turn off the hob

put a textbook between the laptop and yer crotch?

@JohnRennie I'm not naked, I'm in class!

...lol

But the vent is going straight into my balls

I don't get Philosophers

@Phase Glad to know you're a normal human :)

It's like they see fresh Physics graduates claiming that they can revolutionise and model Biology etc, and decide that everything is philosophy

The vent is on the left side of the laptop. Where exactly are you 'nads? Have you temporarily relocated them?

@JohnRennie The desk thingy on the chair is to the right

Hm

John Rennie talking about testicles? I have a faint sense of deja vu..

@Phase Hey, I didn't start it! :-)

@Phase He loves it

MY SCROTUM IS ON FIRE

You two get a [chat]room

@BernardoMeurer please delete this

Philosophy is not everything, but there is a philosophy for nearly everything

It's triggering

as in, given a concept A, you can make a philosophy of A out of it

@0celo7 Quit being a ween

That's offensive

@Semiclassical yeah so the "Ryan read this paper" task has morphed into "Ryan read all of these papers"

I guess L1-L5 on the 2016 version is background

and it took him 10 years to write part II, doesn't sound good

@0celo7 what's your stance on _ Putin _

Great leader, strong man, hated for no reason by wimps

He got given a puppy

but on the flipside

He rules a completely torn apart country and afaik isnt doing much to help

with regards to philosophy, my standpoint is largely that while it's certainly possible to think you're doing physics without philosophy---well, you're wrong

So you'd argue that deriving anything incorporates philosophy? Why?

because derivations are a product of reason and argumentation

@Phase Putin pulled Russia back from the edge of total anarchy when he first came to power. Why you say he isn't doing much to help escapes me.

and while they may arise from empirical observation, it's not just a matter of "I see data and I think of theories"

It seems a bit odd though to label all reasoning as philosophy

@JohnRennie Confirmed fascist

rather, our mind has to organize all of that information into some kind of a whole and draw conclusions about that

@BernardoMeurer because I respect Putin?

@Phase then you've got too narrow a view of both reasoning and philosophy.

@JohnRennie Don't expect my banter to have some deep meaning

Idk. It seems like saying that counting apples is maths

tbh attempting to find meaning in pretty much anything I say will lead most to insanity

counting apples, no. going from observations of apples on the ground to a concept of apples in general as a thing that can be counted

that is philosophy.

@JohnRennie I dunno, I have heard of massive protests throughout Russia against multiple monetary corruptions done by the Russian government of Putin

I wouldn't say I know much about the issue though

When Putin took over the whole country had become institutionally corrupt and was being run by the oligarchs for their own benefit.

The relevant keyword is "He is not Dimon to you"

What is mathematics without formal languages?

Mathematics being philosophy doesn't appear to be a one sided debate though

I'm not saying Russia is perfect, but Putin has done a lot to stabilise it under very difficult conditions.

Or rather, what is mathematics without logic?

I think the larger point is that, even if you conclude that Putin is an autocrat, it's not a matter of "oh Russia was so great and democratic, and then Putin came around"

@JohnRennie I am not defending the pre-Putin Russia, merely saying he can be criticized

Ah, this has a wiki article

@BalarkaSen so can Theresa May and Donald Trump

Er, sure, your point?

it's easy to forget how bad Russia fared post-USSR

Thatcher should come back and rule the world

and how much of that was a result of capitalism coming in and taking over as much as it could

@BalarkaSen my point is that if you're seeking perfection in a leader you'll have a long quest and a fruitless one

side note

Yeltsin's Russia was hella corrupt

These are some polarised autofills

I don't care for a perfect leader. I don't subscribe to any leader.

I am not saying Putin has not done anything to improve Russia, just to clarify

I feel like I've accidentally uncanned some worms

Russia per se doesn't sit in my mind much

US-Russia relations, by contrast...

@Semiclassical Truly

but I think I'd have been worried about that under Hillary as well

anyhoo

It's currently 6PM and I haven't slept in well over 24 hours so

goodnight

the typesetting there makes me mad

what is scal

is it $R$

@Semiclassical I have to read my advisor's thesis. Why can't anything be simple!

@Slereah it is $\mathrm{tr}\,\mathrm{tr}\,\mathrm{Riem}$

lol

@0celo7 Have you looked at Gromov's typesetting/notation on his new diffgeo thing

in arxiv

@Semiclassical this was all a ploy to get me to read his thesis

@BalarkaSen He has two new ones. I read the scalar curvature one and was triggered.

Also I don't understand metric geometry so it was too hard

Ah yes the scalar curvature thing is the one I had in mind

"In [L5] we employed this hitherto unexpected degree of control over the elliptic analy- sis on H \ ΣH to establish the broader framework of a scal > 0-heredity with surgery."

ew

I hate math

what should I do with my life

vary naice

much notation

"torical"

is that what they call toroidal

@BalarkaSen the whole format of the paper is strange

I guess Gromov is just insane (forgive me @ACuriousMind)

I mean that's probably certified truth

@BalarkaSen what's a Gromov boundary?

So say you have a geodesic metric space

Take a point $p$

Look at all the geodesic rays starting off from $p$

@BalarkaSen what's that

Is that a way to say "a sphere"

it means metric distance between any two points on the space is the infimum of the lengths of curves joining them

just the right generalization of riemannian metric vs the metric induced from it

the geodesics are the paths whose length is exactly the metric distance between it's endpoints

Do you mean a complete manifold

I don't think so

there need not be a geodesic joining any two points in a geodesic metric space

Hmm, ok

All I am saying is, you have $(X, d)$ a metric space, and for any $x, y \in X$, $d(x, y) = \text{inf}\, \ell(\gamma)$

infimum running over all paths $\gamma$ w/ $\gamma(0) = x$ and $\gamma(1) = y$

Yes

I have no idea

I picked up stuff overhearing people talk about it

<--- hangs out with geometric group theorists

How does a high schooler hang out with geometric group theorists?

by having no life

@BalarkaSen That seems like a sweet life to me

you clearly have not hung out with geometric group theorists

just think: the originator of the branch is the man himself, Gromov

neeeeeerd

@BalarkaSen are they not analysts?

@Slereah you buy lasers for fun. You're the worst kind of nerd

Lasers are cool

reddit.com/r/WatchandLearn/comments/7870ey/… @BalarkaSen very relevant

(nerd)

I have to decide between taking an astronomy class or analysis ;-;

both of those words are pretty wide

What are the programs

Obviously analysis ;)

What books in each

@SirCumference is that even a question

@bolbteppa you don't like analysis

What's the basis of $SO(3,1)$?

what does that even mean

Oh wait is it just the generators of rotations

that's the basis of $\mathfrak{so}(n)$

I mean "rotation" in the large

Boosts as hyperbolic rotations

Euler angle matrices?

:S

Just trying to figure out how to write the spin connection in gauge form

$$\Sigma_\alpha^{ij}\omega^\alpha_\mu$$

Something like that

I guess it would be like $$\nabla_\mu V^\nu = \partial_\mu V^\nu + ({\Sigma^\nu_{\sigma}})_\alpha \omega_\mu V^\sigma$$

Something like that I guess

oops

Too late to edit

$$\nabla_\mu V^\nu = \partial_\mu V^\nu + ({\Sigma^\nu_{\sigma}})_\alpha \omega^\alpha_\mu V^\sigma$$

There we go

I think that should be the proper form

Does that sound correct

this is done in Weinberg's GR book.

Hm

If i take a weightless box (negligible mass) made up of ideal mirrors (reflecting light almost perfectly) and i fill this box with photons bouncing off of the mirrors, such that about the same amount of photons bounce of each side per second. When i accelerate this box and let it rest after, do the photons inside the box keep the same energy as before the acceleration within the box's rest frame?

How much is it?

It's 22 bucks

I can totally get it

Wait

Which one is it

it's like 200

"Gravitation and cosmology" or "Cosmology"

gravitation and cosmo

cosmopolitan physics

There's a bunch for cheap

hardcover?

amazon.com/…

wow the price went down

yeah

it used to be way more

might be a good time to get it

def

I already have a hardcover

It is ordered

@Slereah I got some money for my birthday and could get MTW

what's feneral relativity?

not sure I should

Study of ferns?

Maybe it's one of those old timey script

ſeneral relativity

@0celo7 What do ya mean?

@SirCumference you're asking about math vs. observational physics

yeah...?

clearly math

it's not a question

but astronomy is so damn interesting ;-;

but so is math...

maybe once you take analysis and become a mathematician you will thank me

I'll be sure to do that if that day comes

i want to become a carpenter

@0celo7 I mean, doesn't astronomy fascinate you at all?

no

we've been over this

@Slereah Huh. In the UK, it's £220 for the hardcover, or £16.50 for the paperback :o

@0celo7 IK, but it just seems abstract to me that someone can dislike astronomy. It's like disliking mango

@Mithrandir24601 gold brick i.gyazo.com/abd2b62d6039abeb29e103ed9b24bc19.jpg

@Blue There's only one class for each of them, and they overlap ;-;

Unless I can duplicate myself, I'll have to choose

@SirCumference I had mango the other day and it was awful. I'm back in the mango hating category.

@0celo7 are you real

Yeah. Fuck complex analysis.