Correct phrasing / use of vocabulary for SR

Vandam

It's not because you have not observed an event that it doesn't or didn't exist yet.
When the signal has not arrived yet, the rover has already landed safely on mars or crashed. Whether it has landed safely or not is already a real fact before you observe it.

<<Physics is an attempt conceptually to grasp reality as it is thought, independently of its being observed. In this sense, one speaks of physical reality>>quote Einstein.

Einstein looked further than the observations. Quite a few people here do not want to look further than observations. Einstein would not share that kind of approach.

ModusPwnd

You can count me as one of those people. And lacking Einstein's approval honestly does not bother me at all.

Observations can be predicted and described, in qualitative or quantitative ways. "Reality" doesn't really matter. You can postulate any type of underlying reality you like. But if that postulate does not increase our predicative or descriptive power then it is superfluous to the theory. If it does increase our power, then its incorporation into the theory is because of observations and observations alone (observations that the postulate increases predictive ability).

Didn't Einstein also say something about not making any theory more complicated than needed? Isn't presuming an underlying reality with no benifit to the theory doing just that?

Vandam

Well, reality doesn't matter to you.
If I see a tree in front of me I have a concept of a tree that was there/is there independent of observations. You and many others on this forum reject this because you find this philosophical mumbo jumbo. I'm not a solipsist.

ModusPwnd

I dont think it matters with respect to science. Outside of science I can conject and hypothesize away.


Aww, thats not true man. That like saying a blind mans knows what red looks like. If you never had an observation of a tree how would you create that concept to begin with? Its the collection of many observations you have made over your life that forms the concept of your tree.


I reject because I dont see it adding any predictive or descriptive power to our theories. In that sense it is completely superfluous and thus irrelevant to science. It may be relevant to other philosophical areas, but not 'natural' philosophy, not science.

A key tenant of science, IMO and I think many others as well, is that all theories are tentative with respect to new observations. All of them. Presuming that any are immune to new counter observations is denying any further investigation. That is counter to science. This is not nearly as hard of a line as I think of a solipsist as taking. But if it is, so be it. We are talking science here - not philosophy at large.

ghwellsjr

Maybe not in this thread, but haven't you seen many cases of people insisting that it's important for an observer to have a perspective or a point of view from his own rest frame, even he's not inertial?

Vandam

I'm not saying observations are not important.
I'm saying that based on the observations we know what the exteriour world is made of independent of observations: I see a tree because there was a tree even before it was observed.

In a frame two events are observed simultaneous because they are simultaneous in that framle even if not observed. And those two events are non-simultaneous in another frame because they are non-simultaneous in that frame, even not observed. That's SR and block unverse. For me Block universe is the only correct physical interpretation of SR. All the rest I consider philosophical ad hoc explanations. Of course you do not agree with what I say.

DaleSpam

Nor are most of the people who disagree with you on some of your more extreme block universe positions.

bobc2

"...extreme block universe positions"??? I've seen nothing extreme about the positions presented by Vandam. Block universe is widely discussed among physicists--quite a few references have been cited on this forum. LET is usually the concept offered as proof that block universe is not the only world view among physicists. I personally have not dug into the details sufficiently to critique LET.

My grad school prof discussed it only briefly and basically dismissed it as an alternative to the Einstein-Minkowski 4-dimensional universe. So, I took on that same attitude without really doing my own homework on the subject. I've always assumed that LET did not have the natural connection to general relativity that is had by special relativity. The little homework I did with LET years ago left me feeling that one would have to deal in tedious detail with many different special relativity effects and examples before considering LET a valid theory. Contrast that with the ease that the 4-dimensional universe concept clarifies so many different special cases of phenomena related to special relativity.

Vandam

Extreme block positions....
At least I have a position. After all the posts I've read of the non block followers (like you) I still do not understand a word. Even if you try to explain it.
Or there are a lot of solipsists on this forum. Or you all believe in LET, I.e. mathematical illusions to save the physical ether. And probably a combination of both.
Or what else is it?
That all has nothing to do with SR. Solipsism is for philosophy forum. And LET is an ether disaster and old school (Lorentz himself admitted it). So in fact both approaches are off topic on this SR forum.

DaleSpam

The block universe is my preferred interpretation. I just recognize that it is only an interpretation.

So please stop bringing it up here.

PeterDonis

And your conclusion was, and is, incorrect. I'm sorry that that is still not clear to you even after all the discussion. But that's off topic for this thread.

In any case, I don't see how your beliefs about my beliefs are relevant to the simple question of whether or not SR requires hard determinism. I addressed that in post #31 in this thread; do you have any comment on what I said there?

PeterDonis

Yes, it does. As a *model*, with a well-understood domain of validity, SR works great, and the 4-dimensional spacetime concept makes SR easy to understand and use.

As a theory of everything, it's wrong; so trying to use it to justify claims about the ultimate nature of reality doesn't work too well.

I have the same question for you as I asked Vandam: do you have any comment on what I said in post #31?

Vandam

There's a lot off topic for this thread already.
But it might be the core problem of our disagreement. The wrong phrasing and clumsy vacabulary in SR literature is partly due to refusing to accept the physical implications of SR.
A lot. But that's far too off topic in this thread.
And as long I do not know what kind of physical interpretation of SR you (and others) adhere it is pointless to start discussing that topic.
I started a new thread on 'observation' that you might find interesting in above context. See:http://www.physicsforums.com/showthr...23#post4048623

PeterDonis

Sigh. Perhaps you can at least answer an even simpler question: do you think SR, as a physical theory, is exactly correct?

I'll take a look.

DaleSpam

I don't adhere to any. That is the whole point of interpretations, they don't need to be adhered to, there is no experimental evidence to choose one interpretation over another.

My favorite interpretation is the block universe, but I switch between interpretations and use whichever is most convenient for the problem at hand.

bahamagreen

You should realize that when you examine the clarity of vocabulary as it relates to the meaning of concepts that you are doing fundamental philosophy. "Metaphysics" does not mean "against physics", "opposed to physics", or "not physics"; it means "after physics" - just the label given to the section that came after the "Physics" section... (Aristotle did not name it himself, that was done later).

As Wiki notes,
Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:
"What is there?"
"What is it like?"

PeterDonis

Exactly.