joigus

7 hours ago, swansont said:

You say this, but have not actually shown it to be true. You have not done any analysis of the light path in the moving frame when accounting for the motion of the light.

Very good point. +1

While it is true that you've show an intuition of something unexpected, we know how all kinds of very similar naive intuitions fail one by one when you apply the formalism.

Can you provide equations, showing the velocities and the angles in both inertial frames, or are you expecting everybody else to believe it only based on intuition? Do you want somebody else to do the analysis for you?

IOW: Why should anyone bother with this?

3 hours ago, swansont said:

We shouldn't ponder things that might be bad? How else do you prevent them from happening? Isn't pondering bad things that you might prevent them good for the species?

 

Having knowledge and using knowledge are two different things. 

 

Which brings us back to the poll. I would divide things between useful and not-useful. Good and bad are somewhat arbitrary distinctions. Eise mentioned fission. I'll make it simpler: the knife. Is it good or bad? People use it as a weapon, but surgeons use it to save lives. A lot of people use them to prepare food. I don't think you'll ever get a clear answer because good vs bad is too simplistic a distinction and driven by context, IMO.

"Unchecked by philosophical concerns" doesn't cut it, I think. You can't know the results of an experiment when you are delving into new territory, and can't know how people will use the resulting scientific knowledge. All we know is "here be dragons" probably applies.

 

You make some very good points here. +1. You also introduce an element which must have slipped my mind, which is the one of usefulness. This element of usefulness actually had more to do with the original meaning of my question. The ethical question, important though it is, was not what I had in mind.

That doesn't mean I don't welcome any other aspects that other members may have in mind. I do.

Also, I'm not saying that the ethical question is out of reach for rational thinking, which I think it is. Concepts such as common sense, equanimity and the like are quite useful (again) to get to working standards for ethics. Golden rule is the best example.

I agree that potential for harm should not be the criterion upon which we base what we ought to know and what we oughtn't.

2 hours ago, Eise said:

My interpretation of the paradise story contains a certain wisdom: 'knowing' the difference between right and wrong, good and evil, led to the banishment of Adam and Eve from paradise.

And a take-home lesson about diet.  

2 hours ago, Eise said:

What is 'bad science'? E.g the development of nuclear fission: it gave us nuclear energy and an arms race. Or is 'bad science' science that is methodologically unsound?

If the latter, then bad philosophy would be that you stop with an honest investigation when you do not like the result of your reasoning.

Maybe bad science is science unchecked by philosophical concerns?

1 hour ago, Eise said:

I tend to disagree. In a graph without time, you would say that to every x belongs a value f(x). So e.g. for x = 2, f(x) = 4, for x = 3 it is 9 etc. That is a 'static' view. You can also ask for the derivative, e.g. for x= 2 f'(x) = 4, for x = 3, f'(x) = 6 etc. But that is again a static view. Only in a 'dynamic view', where you continuously change x and see how f(x) changes dependent on x, your point becomes valid. But with that, we have introduced time, namely on the x-axis.

In my opinion you are using metaphorical speech. Imagining how we 'run' through the values of x, we see how f(x) varies.

The technique that Markus describes is actually something I've seen done in theories of gravity when people try to discuss emergent time. But I think you're right that the sequencing aspect is lost or not entirely obvious. That's why I suggested the introduction of a proper length parameter as the most likely candidate to where, mathematically, time comes from.

Suppose you have a physical system with variables (x₁,x₂,...,x_N). If you had N-1 implicit equations or "constraints":

f₁(x₁,...x_N)=0

f₂(x₁,...x_N)=0

...

f_N-1(x₁,...,x_N)=0

This would amount to having a common history for all the x's. The complete deterministic solution to a particular system's evolution deployed before your eyes. Giving values to all of them except one allows you to infer the value of the remaining one. Although that value may not be unique. For example. At a certain point in your life you asked your sweetheart to marry you. That's x₇=1. But there are two values for the answer that she gave you: x₈=1 and x₈=0. That's because at some point she said "no", you asked again a week later, and she said "yes". Assigning values to the rest of the variables of the universe, you can get "back" to the event you want to picture. This gives you a bird's eye view of the history.

If you have a metric for the x's, you can do something quite impressive in principle if your metric is positive definite and based on a quadratic form. You build the infinitesimal interval along your implicit curve:

ds²=g_ijdxⁱdx^j

and define your sequencing (primitive time) as either,

dt=+sqr(g_ijdxⁱdx^j)

or

dt=-sqr(g_ijdxⁱdx^j)

I know @Markus Hanke has some exceptions/criticism for this procedure. But I think it's a mathematical language that very much fits what we know about the mathematics of the world, has many of the essential features of time in it, and leads to a quite clear-cut setting (if not solution) of the problem: Why is it that we only see the world evolve in one of the two orientations that the metric allows you to pick? The mathematics seem to confirm that: You chose one or the other, but once you're fixed on one, no valid re-parametrization can give you the other.

I have an intuition that this may have to do with the Michel/Studiot argument about the cup of tea. But I must go over their arguments again, I must say.

Edit: x-posted with Eise

Edit 2: The metric should be defined on the f's, not the x's. So it'd be,

ds²=g_ijdfⁱdf^j

Trying to use reason to understand the internal arguments of religion is as hopeless as trying to thread a needle through a loop.

1 hour ago, Strange said:

If your intuition is based on "god did it" then that cannot lead you anywhere because your gad can do absolutely anything at all. You would have been able to predict the results of the double slit experiments, etc. simply by an intuition about "what would my god do".

People were led to develop quantum theory by following the evidence, and using their intuition about how mathematics could explain that.

If your intuition is based on a working theory, then you can extend, expand, develop new tests of that theory, etc.

Good point. +1 Why did god do it? Many scientists in the past, feeling very uncomfortable about making statements that denied god, chose to phrase the question as,

Why did god choose to make the world like this?

One answer for every question "God did it" is clearly not good enough.

8 hours ago, Markus Hanke said:

I wish I knew more about QFT, I never got past some ‘first introduction’ type texts, so I only know basic concepts and rough outlines. For some reason I am finding the subject difficult - not in terms of understanding the concepts, but in terms of the mathematical formalism, which I just can’t seem to really get my head around. 
Another peculiar thing about QFT is that for whatever reason it seems to set off alarm bells somewhere within me. I do not for a moment doubt its empirical success as a model, but something just seems off about it. A lot of things in it appear very ad-hoc, very messy, like an ensemble of disjoint Lego pieces that a child has put together. I just can’t, for myself, motivate the framework from fundamental considerations (as is possible to do in GR e.g.), so it seems invented and artificial. Of course I can’t offer a proper objective argument, but my intuition is telling me that we are missing something important here...something just doesn’t sit right, though I can’t put my finger on it why that is. Even the basic concept of an operator-valued field seems somehow dubious to me, and I don’t quite know why.

Of course at the moment it is the best framework we have, and it works well, but...

Believe me, I share much of what you say here. And you've explained it very eloquently. +1. I'm struggling with many of these issues right now. It doesn't help that the subject is vast, also.

I have this intuitive feeling that the situation will be enormously clarified once we understand better the role that the scalar field is playing in the whole business. Right now, the scalar field is not fundamentally understood in QFT. It's used as a device to parametrize certain constraints. The scalar field comes up in just about any model-building way that people have invented to implement known facts that we don't quite understand.

17 hours ago, andsm said:

Energy is primitive concept. It is  enough to have symmetry to time translations, and you would have energy conservation law. I wrote how symmetry to time translations arise in my model.

Energy is not a primitive concept. You can actually re-formulate classical mechanics pretty much without it with the Jacobi variational principle. Take a look at Barbour-Bertotti mechanics, e.g., who re-discovered the Jacobi action principle. The action would be,

\[S_{BB}=\int dt\sqrt{T}\sqrt{-V}\]

The theory would be diffeomorphism invariant with one constraint equivalent to E=0. You can solve classical mechanics one energy at a time. But energy as we know it looses its "primitive" meaning. No version of mechanics, GR or other dynamical theory of physics is built from the concept of energy.

As always happens with physics, the more general your framework is, the more abstract the primitive quantities become. The primitive entity is the Lagrangian, but the meaning is much much less clear.

Oh, and in GR energy is not conserved in general. Some metrics have a time-like Killing vector and then you can derive a particular "version" of energy. Energy in GR is not a very useful in general, very fundamental concept.

I could say more, but this is starting to be a pain in the neck.

Do you want to re-activate the thread? Are you still having problems with the concept of enthalpy?

The question is the same.

4 hours ago, andsm said:

Many singularities? May you show even one?

All of them, AAMOF:

\[f\left(\alpha\right)=\tan\alpha\]

\[\alpha=\frac{\pi}{2}\left(2k+1\right),\:k=0,\pm1,\pm2,\cdots\]

Complicated women are the best.

2 minutes ago, andsm said:

And next yes, I took S_g from excellent textbook.

Thank you. Some gibberish you invented must be zero. Only non-trivial stuff comes from a book.

No more questions, your honour.

3 minutes ago, andsm said:

 

23 minutes ago, joigus said:

You also copy-paste the Lagrangian of GR as if it were derived from your idea. It's not. You've just attached it to your idea.

It is simply wrong statement.

Do you disagree with derivation of action variation in my article? If the derivation of action variation is correct, it means I derived equations of GR too.

You do. And I quote:

Quote

The action for a physical system in some field usually looks like: 𝑆=𝑆𝑚+𝑆𝑓+𝑆𝑚𝑓 Here, 𝑆𝑚 is that part of the action that depends only on the particles properties, i.e.

Then you narrow it down to a simpler form. And then you pull the rabbit out of the hat about here:

Quote

Now we can proceed to the derivation of the gravitational field equations. These equations are obtained from the principle of least action 𝛿𝑆=0, 𝛿𝑆=𝛿(𝑆𝑚+𝑆𝑔)=𝛿𝑆𝑚+𝛿𝑆𝑔

Variation 𝛿𝑆𝑔 is equal to [5,p. 355]:

𝛿𝑆𝑔=−𝑐316𝜋𝑘∫(𝑅𝑖𝑘−12𝑔𝑖𝑘𝑅)𝛿𝑔𝑖𝑘√−𝑔𝑑Ω

And what is [5, p. 355]? Nothing other than:

Quote

[5] L.D. Landau, E.M. Lifshitz, Field theory, vol II, izd. 7, Moscow“Nauka” 1988

You're copy-pasting, as I said, from excellent physics books. How could I disagree with Landau and Lifshitz, Field Theory, Vol. II? What I'm saying is that none of this appears to follow from your ideas. Not as far as I can see.

Here's a try to guess at what you've done:

1) Define an arbitrary map (not even well defined mathematically) from t, x, y, z and claim that you've shown space and time as "emergent" from your singular variables.

2) Copy and paste standard equations from physics books.

3) Puff it all up with lots of words. Throw in "conscience" and "observer" and "hypersurface". Big words.

Only thing I can say is I'm sorry I can see right through it. We must be connected through a hypersurface.

32 minutes ago, andsm said:

About inverse mapping - you mean what there is no bijection for the mapping or what?

 

Exactly. Not invertible at infinitely many points. What's that multi-branching? Conscious projections? Observers?

18 minutes ago, joigus said:

You also talk about energy long before you talk about Lagrangian formalism or anything that logically amounts to it. And energy is a consequence of it. Energy is not a primitive concept.

Sorry, you do introduce it later. But I don't see how this emerges from any new assumptions of your own.

Just now, andsm said:

Sorry, what is alphas?

𝑣=𝑣𝑡tg(𝛼)To find the components 𝑣⃗, one can divide the rotation into relative to the axes rotations: 𝑣𝑥=𝑣𝑡tg(𝛼𝑥) 𝑣𝑦=𝑣𝑡tg(𝛼𝑦) 𝑣𝑧=𝑣𝑡tg(𝛼𝑧)

Your time and space have infinitely many singularities. And there's no inverse mapping from the alphas. It doesn't look like your v's map to the world we know and love.

And no offence, but the rest of it looks like you're just copy-pasting common physics and puffing it up with lots of words, TBH. Example: Because there are hypersurfaces, there must be curvature, and thereby, there must be a geodesic equation. So you write down the geodesic equation. Nice.

Why? What particles are moving along them? Where are these particles?

You also copy-paste the Lagrangian of GR as if it were derived from your idea. It's not. You've just attached it to your idea.

You also talk about conscience giving rise to the world. Whose conscience? Mine? Donald Trump's? How many are there? How do they give rise to the world?

You also talk about energy long before you talk about Lagrangian formalism or anything that logically amounts to it. And energy is a consequence of it. Energy is not a primitive concept.

I have also serious doubts that you can construct pseudo-vectors like angular momentum, helicity, etc.

Need I say more? Maybe I do.

When it's being a particle, it's not being a wave; when it's being a wave, it's not being a particle.

It's like a writer who plays golf. When she's playing golf, she's not writing; when she's writing, she's not playing golf.

Unlike businessmen, who can play golf and do business at the same time.

Edit: If you're puzzled by QM, you're in very good company. +1

14 minutes ago, lidal said:

my theory does not provide a new model,

You keep using that word, "theory".

1 minute ago, studiot said:

What makes more sense is the fact that the air pressure (whatever its function of r may be) must be a maximum at the centre and decrease towards the surface.

Thus if the equation ere to be written

P_r = P₀  - f(r)

which says in words that "the pressure at radius r is the pressure at the centre minus some function of the radius (which could be a suitable integral)"

True. There's also the problem of T(r), because that's not a constant with r. I suggest to let @Martoonsky speak.

6 minutes ago, studiot said:

This is not what Martoonsky says.

Sorry, we almost x-posted. You didn't see my edit. The only thing that makes sense to me for the red line is the g(r) field strength.

Edit: The only thing that doesn't check with me is the sign. It should be negative (inward pointing). 

3 minutes ago, studiot said:

What is V  please?

\[V_{\textrm{int}}\left(r\right)=G\frac{M_{\oplus}}{2R_{\oplus}}\left[\left(\frac{r}{R_{\oplus}}\right)^{2}-3\right]\]

\[V_{\textrm{ext}}\left(r\right)=-G\frac{M_{\oplus}}{r}\]

Edit: It's the line going down with distance linearly.

Edit 2: Sorry, that's g. The line going down linearly with distance is the gradient, that is, g.

4 minutes ago, studiot said:

Thank you for the reply.

Are you seriously suggesting that the density (blue or red  ???) is zero at the centre?

Red is V; blue is rho times g. g is zero at the centre.

2 hours ago, joigus said:

Yes! It's only that there were several lemmas. Wick's theorem was the re-ordering trick; and then you sandwiched the operators with the vacuum and got the ready-to-use result, which maybe had another name, an acronym like FDW or something... But Wick is one of the central names in the bunch of results.

Nah, that's LSZ:

https://en.wikipedia.org/wiki/LSZ_reduction_formula

That comes later. It's Wick's theorem I was talking about. Thank you, @Markus Hanke. +1

6 minutes ago, J.C.MacSwell said:

It was pertinent (in my mind at least) to Endy's post. He seemed to intuitively recognize that at the centre something with regard to pressure went to zero, and for the reasons he stated, which made that point unique. (Jupiter OTOH could have any number of points of zero gradient at local maximums or local minimums at any given time)

It wasn't the pressure itself that went to zero though. It was the gradient.

It has to hit a maximum somewhere down there...

I agree. "Out of equilibrium" I didn't mean as a serious objection. It was meant for completeness.

21 minutes ago, J.C.MacSwell said:

Somewhere near the centre of Jupiter (many factors might put it at other than the exact centre of mass) the pressure would hit a maximum. At that point the pressure gradient would be zero. 

I see no way in which this could be wrong! +1

Edit: Sorry; I can only see one: The system is not in equilibrium.

Mmmm. Suggestion: Let it grow a little bit more and take another picture.