Dark Matter sheds some light

The non amateur stuff. Hawking, black holes, that sort of thing

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Cliff
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Post by Cliff »

Dear Davep and Brian
I do have some sympathy with regards Brian's use of words.
I think it could be said that at least some scientists are pretending to be modest by using such terminology as "deduce", quite often they might be quite happy to impose their ideas on us if they could get away with it.
Take the case of nice scientist Edington and chandraskar as an example.
Best wishes from Cliff
brian livesey
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Hopi thinking..

Post by brian livesey »

As far as I know,Cliff, scientific laws are human constructs, whereas Nature only knows change. This was why I used the word "impose". If we take the "Law" of gravity,what we have is the abbreviated motion of a body, that saves having to work out all of the body's motion. The "law" exists for the purpose of economy of thought. Of course,when something unexpected arises, we make "corrections" to the "law". The idea of "gravity" is an abstraction. The native American Hopi people say that when a body falls,it does it of its own accord,no concept of "gravity" is involved. The object simply falls. This is just as valid a way of looking at :wink: motion as our own.
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davep
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Post by davep »

I'm not obviously and visibly falling right at this moment. Does that other way of looking at things explain why I feel gravity while I'm sat here not falling?
brian livesey
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Feel the force..

Post by brian livesey »

It's more than likely that a Hopi will feel the same sensation too,and that there'll be a Hopi explanation for it that's compatible with the Hopi way of life. How we interpret Nature, depends on our frame of reference. The idea of a separate force of "gravity" (i.e., the "fetishism of forces") permeating space and acting on bodies as a kind of imp,is a human construct,but it does have practical applications.
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davep
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Post by davep »

Tell me more about this "imp" and this "fetishism of forces". I reads like you're suggesting that physics is a form of sophistry. Would that be a correct reading?
brian livesey
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Now we see it,now we don't..

Post by brian livesey »

If we remove the body,the "gravity" disappears with it.
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davep
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Post by davep »

How does that expand on the idea of a "fetishism of forces"?

How quickly would the gravity disappear?
brian livesey
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Acting bodies..

Post by brian livesey »

The idea that "forces" exist as independent entities is an illusion: it's the bodies themselves that act; we ascribe "forces" to them. I don't understand the point of your last query.
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davep
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Post by davep »

I can't say I've ever seen a suggestion that forces exist as independent entities. Could you give me an example of this?

My second query was about your thought experiment regarding the total removal of a body. Assuming for a moment that such a thing were possible, if you popped the Sun out of existence, how quickly would we notice this change, in terms of gravity, here on Earth?
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Bodily interactions..

Post by brian livesey »

It's natural ,possibly for conveniency's sake, for people to speak of "gravity" as an independent force (Newton admitted that he couldn't account for action at a distance). They might say, for example,that a slate fell from the roof because of gravity. The actual cause was the interaction of two bodies, Earth and slate, which they've ascribed to
gravity alone. The effect of the Sun physically disappearing in terms of "gravity" (i.e., the interaction of two bodies) would,I'm guessing,be instantaneous.
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davep
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Post by davep »

I can't help thinking that naming and describing the interaction is no different from naming and describing the slate or the Earth. If I'm to understand you correctly (and please correct me if I'm not), you're suggesting that the four fundamental forces are a greater abstraction, a greater human invention, than, for example, actual "matter". Is that a fair understanding?
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Metaphorically speaking..

Post by brian livesey »

Earth and slate are tangibles. The four fundamental " forces" are mental constructs: metaphors of reality.
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davep
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Post by davep »

When you touch that slate, what's happening?
brian livesey
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Metamorphese..

Post by brian livesey »

We probably can't say without resorting to metaphor. All that we can say about "gravity" at the experiential level, whether we're Hopi or English,is that there's a downward acceleration. If we try to explain why this should happen,we are being metaphorical. The English metaphor for "gravity" is expressed as Newton's equations.
There are still people who regard gravity as a fetishistic, autonomous,"something" acting on bodies ( a view derived from old-fashioned mechanical materialism),instead of the bodies acting on each other.
At the cosmological level,Einstein dispensed with the idea of "gravity" tugging on bodies and replaced it with the metaphor of the "Geodesic": bodies follow the shortest route along curved lines. Einstein knew,of course,and said so, that four-dimensional,curved,space-time is a set of formulas and doesn't really exist.
It doesn't end with "forces". Let's consider electro-magnetic waves. Physics textbooks tell us that colours are propagated by different wave lengths of EMR. This can lead to the misunderstanding that "waves" are the true reality and colours are effects. It's really the other way round: colours are real and "waves" are mental constructs.
The mental concept of "waves" has practical applications,but the "waves" are no more real than a landscape painting can be said to be an actual landscape.
Now take the metaphor of the "atom". It was once thought to be not unlike a spherical pudding with plumbs embedded in it. Then came the Bohr atom,a reassuring miniature "solar system", comprising discreet particles. As practical physics progressed, the discreet particles turned into ghostly "fuzzies". Nowadays, physicists refer to "probability waves". If we ask the physicist to demonstrate a "probability wave",he points to an equation.
"Forces" and "waves" are metaphors of reality,expressed as equations. Reality comprises phenomena themselves: bodies,colours and other sensations. Apologies if I seem to be preaching to the converted,but there may be some Forum members who are not acquainted with some of these points. :wink:
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davep
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Post by davep »

No apology is needed, expanding on your one-liners is useful because it helps in understanding what it is you're trying to say -- it's greatly appreciated.

I am, however, still unsure about this "fetishistic" approach to talking about forces that you've spoken about. You seem to be concerned with the idea that some of the ways we communicate an understanding of phenomena are simply "metaphor" whereas communications of the understanding of some other phenomena are not a metaphor because they relate to "tangible" items.

On the one hand I can sort of see where you're coming from but what I can't get past is that it's a self-defeating argument in that it's all about our senses and how we communicate (introducing "tangible" causes that problem for me). I can't get past the view that it's almost a reductio ad absurdum approach to dealing with our understanding of phenomena we observe. Of course some explanations are metaphorical, that's rather obvious and should go without saying. But, if we take that line, then we've got to keep reducing the argument down to the level that we acknowledge that all explanations are human-created. This comes as no surprise, they're about communicating ideas to humans.

In other words, you seem to be making the point that the map isn't the territory. Thing is, that's a point that's well understood, but it doesn't stop the map being useful.

So, I'm left wondering, when you point out this obvious fact what are you trying to say?
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