Dark Matter sheds some light

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

Moderators: joe, Brian, Guy Fennimore

joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Re: Metamorphese..

Post by joe »

brian livesey wrote:"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:
Surely forces and waves ARE reality. In order to describe them or even talk about them we have to modify our vocabulary to the level of the discussion. We can talk about electromagnetic radiation as "light" when discussing what we see in general. If we are talking about a rainbow then we have to use words like wavelength and frequency and when we talk about particle interactions we have to then use equations. These equations are used because the reality we are discussing, at this level, is not "there" at "that place" at "this time", etc. and the only language that is useful is mathematics but it's still the everyday stuff of reality......as far as we know.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
davep
Posts: 2814
Joined: Fri May 06, 2005 11:07 am
Location: South Lincolnshire
Contact:

Post by davep »

I think what Brian's trying to drive at is that the rainbow, to pick one of your examples, is only "there" because you're evolved to process certain wavelengths and to ascribe a meaning to them when you perceive them.

"There is no rainbow".

At least, I think that's what he's trying to get at. Although I suspect I'm still missing the point of what he's saying.

Or, as you'll understand, and I'll regret saying because you'll probably respond in kind and I don't speak French ;): Ceci n'est pas une pipe
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

Yes, I think I can see roughly what Brian is saying and to a large extent I agree, "blue" exists nowhere except in my, or your, brain. Where we get in to trouble, and I think this is what you are hinting at, is that if the "rainbow" or "slate" or "gravity" is not what or where we say it is, then we can make up some other words to describe it - but we may as well stick with the ones we have. We still have to deal with them and dealing with them is roughly what reality is. N'est ce pas?
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
davep
Posts: 2814
Joined: Fri May 06, 2005 11:07 am
Location: South Lincolnshire
Contact:

Post by davep »

joe wrote:We still have to deal with them and dealing with them is roughly what reality is.
Exactly. Being self-aware enough (or no-self-aware enough if you're, say, Buddhist ;)) to understand that communication in this case is the map, not the territory, is one thing. But dismissing the map because it isn't the territory wouldn't seem like a useful thing to do.
joe wrote:N'est ce pas?
(Hits Google). Oh, wait, should I have just answered with "oui" or "non"? :)
brian livesey
Posts: 5442
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Where are they?..

Post by brian livesey »

By "reality", meaning everything that exists. Show me "gravity" ( I don't mean a falling body). Show me an electro-magnetic "wave" ( I don't mean a visible representation on an oscilloscope screen).
brian
davep
Posts: 2814
Joined: Fri May 06, 2005 11:07 am
Location: South Lincolnshire
Contact:

Post by davep »

So you're saying that "reality" is defined by the things that you can personally perceive?

Couldn't someone equally ask you to show them something but do so without utilising a force?
brian livesey
Posts: 5442
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Phenomena..

Post by brian livesey »

Not necessarily. In saying "everything that exists", meaning phenomena that we observe,plus the phenomena that may exist outside of our experience.
Please enlarge on your second question.
brian
davep
Posts: 2814
Joined: Fri May 06, 2005 11:07 am
Location: South Lincolnshire
Contact:

Post by davep »

So you're actually saying that "reality" isn't defined by what we can perceive?

The second question, in other words, is: How could I show you the slate, allow you to check that it is "tangible", without someone being able to say "ahh, but you used forces to do that!"?
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Re: Where are they?..

Post by joe »

brian livesey wrote:Show me an electro-magnetic "wave" ( I don't mean a visible representation on an oscilloscope screen).
The problem with your request, Brian, is that you are asking to be"shown" something which would necessarily involve the very senses that you are calling into question.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
brian livesey
Posts: 5442
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Phenomena behind the phenomena..

Post by brian livesey »

To give "forces" and "waves" an independent existence is to posit phenomena BEHIND the phenomena (e.g., "gravity" behind Earth and the falling body).
A human attribute,necessary for survival,is to be able to separate out the parts of reality by naming them. Of course,this is a convenient illusion: Nature knows no boundaries, it exists as a single unity. What we call the "boundaries" between phenomena are blurred, they merge in a process of endless change.
To invent the concept "Gravity",is to abstract a part of Nature that,in reality,has no independent existence. What we call "Gravity" is only a mental exercise, but obviously has practical applications. This is all that I'm saying. Mach knew it, Deitzgen knew it, Einstein knew it, and Pannekoek knew it.
brian
davep
Posts: 2814
Joined: Fri May 06, 2005 11:07 am
Location: South Lincolnshire
Contact:

Post by davep »

I wouldn't disagree with that. What I'm trying to get a handle on is why you single out forces. Are those things that you'd call "tangible" not also convenient abstractions?
brian livesey
Posts: 5442
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Tangible intangibles..

Post by brian livesey »

Tangibles are abstractions in the sense that they were once thought to consist of tiny,hard,particles called "atoms". Now "atoms" are described as "probability waves".
brian
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

I don't count sheep to fall asleep anymore. I imagine endless potential probability waves that remain unobserved, one after the other, in increasing complexity, that leads eventually, to a universe where all these potentials stay "uncollapsed" and therefore the whole of existence waits to become reality. Usually does the trick. (Just finished two weeks of day and night work and I'm de-mob happy :shock: )
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
brian livesey
Posts: 5442
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Getting to the bottom of the matter..

Post by brian livesey »

That's incredibly imaginative,Joe,but that's all it is, it isn't reality itself. All we observe are PHENOMENA. What we call "matter" is,of course,like everything else we attach names to,an abstraction: we've "separated" it out,abstracted it, from the rest of reality,but it's only a mental exercise; Nature knows no such divisions.
We can liken reality to the aggregate inside a concrete mixer, the parts being constantly churned over; no part of the aggregate can claim to have precedence over the rest. If we select one piece of the aggregate (say, "gravity" or "waves",which exist as mental phenomena only )and then attempt to use it to account for the rest,we make an error. "Matter" (I'm assuming that Dave's referring to matter inconcreto (the pun is unavoidable) is only one aspect of reality.
The word "matter" comes from "materia",which means the whole of observed reality,so there are other forms of matter besides the "solid" stuff. For example,consciousness and democracy. It might seem odd to introduce "democracy" into the discussion,but it exists as a social reality. Social realities are just as real as pebbles on a beach. If you don't believe this,try living without money,or be the victim of a war.
To return to Cliff's original point about the possibility of scientific laws breaking down,he's right. Either they have to be more-or-less drastically revised,or they might even turn into their opposite. Look how far atomic theory has come - from the "plum pudding" structure,to the "probability wave".
brian
joe
Site Admin
Posts: 4382
Joined: Fri Dec 03, 2004 11:24 am
Location: Greenwich, London
Contact:

Post by joe »

My sleepy comments were in jest really but I do understand where you are coming from. A cynic might say that you are only stating the obvious :wink: . If universal expansion is a reality then it is obvious that everything is part of the whole.

What we observe are phenomena to which we apply names - waves, gravity, apples, etc. What is an apple? Is that part of reality or is the collection of atoms that form an apple more real? Are vibrating strings more real again? Or a local curvature of the fabric of universal space-time? Or that part of the universe that I'm not ignoring?

It gets a bit more complicated when you use one "phenomenon" to describe another "phenomenon", as you rightly pointed out, but is that not what scientific hypotheses and theories are all about? Finding the best description of what constitutes reality? Newton described gravity one way in his Principia. Einstein described it in another more accurate way and there will probably be further modifications in my lifetime. It's the same with descriptions of matter. It might not be reality if reality has to be the most fundamental and accurate description of the fabric of the universe but it is the best we have at the moment.

Maybe.
200mm Newtonian, OMC140, ETX90, 15x70 Binoculars.
Post Reply