General, Introductory Physics

[jrs]

Felipe:

I am not sure whether you are making a substantive point or merely quibbling about semantics.

When I say "space", I do NOT mean "nothingness" -- the mere fact that there is no matter present.

If you want to insist on that meaning for "space", then let me speak of the gravitational field. It exists everywhere: both within matter and where there is no matter. The gravitational field definitely has quantitative attributes which can be measured.

If Objectivism is going to insist that only palpable material objects exist, then it is just plain wrong.

[HaloNoble6]

To essentialize Necessary_Truths point, gravitational fields are part of the identities of certain entities. This means that the concept "gravitational field" too, like the concept "nothing," is strictly a relative concept anchored to an entity. Further, your claim that "nothing" or "space" is "an entity" just because entities and/or their qualities (such as the fields they produce) must pass though "nothing" or "space" is again using my original point yet not acknowledging its validity: could you have pointed to "space" or "nothing" without mentioning the fields or entities that can fit or pass through that "space" or "nothing?"

And by the way, never did I mention the concept matter (which is something even today we don't understand completely, speaking in terms of physics); you're again introducing unnecessary concepts of physics to try to refute a basic philosophical fact. It makes no sense to talk about "nothing" or "space" without reference to the entities and/or their qualities that could exist in that "space." You cannot conceptually equate non-existence with existence, which you are attempting to do when claiming that "nothing" is an entity. Space is not an entity, it is mearly the absence of entity.

[EC]

I recommend you all check out my comments in the Atheist thread in regards to space and it being finite instead of me rewriting the entire thread here. Also check out Alex's essay that I linked to in that thread; it explains why the Universe is both finite and unbounded, which properly negates the need to posit the existence of an "infinite" universe when all the terms are defined correctly.

Space amd time are relational concepts that only exist between existents. The universe is eternal, it has always existed and will continue to do so, eternally. What we call the "big bang" event was just the universe undergoing a phase transition. The universe is neither expanding nor contracting, because that whole concept is absurd. It is staying exactly where it is and where it has always been, eternally. And don't take the previous comment to imply that Objectivism in some way rejects GR, because it does not. The non-Euclidean geometry described by GR's field equations simply decribes the way matter propagates in relation to other matter, energy, pressure, etc., it doesn't actually decribe the real curvature of a "spacetime". But instead decribes the curvature of the paths matter traverses.

Also Objectivism does not reject QM, which would be rediculous, but instead rejects the faulty interpretations that lead to contradictions of the law of identity, or denies causality and deterministic behaviour, etc. Leonard Little's Theory of Elementary Waves is fully consistent with Objectivism and every experiment that has ever been conducted to empirically test QM.

[jrs]

Necessary_Truths:

You said "Gravitational fields ... are just relationships between material things ... they do not exist on their own.".

First, there is only ONE gravitational field, not one per gravitating mass.

Second, the unique gravitational field is not merely a relationship among masses. For example, there is reason to believe that there are gravitational waves which travel at light-speed and are not tied to the current position of any mass.

You said "... material things which include all types of particles, not just the ones with mass ... ".

Are you conceding the existence of photons and gravitons?

You said "Gravitational fields ... represent how much acceleration a material thing will experience given that it has x amount of mass and it is y distance away from these other things.".

The metric (distance or duration) of space-time is the gravitational potential-field (analogous to voltage). For example, clocks run more slowly near massive bodies.

The affine connection (Christoffel symbol) is the gravitational force-field (analogous to the electric field). It determines the acceleration of free-falling bodies. Very roughly, this is the gradient of the rate that time passes (physical time over coordinate time).

Felipe:

Einstein's view was the opposite of yours -- that objects are merely regions where the fields are especially strong and perhaps knotted in some way.

You said "It makes no sense to talk about 'nothing' or 'space' without reference to the entities and/or their qualities that could exist in that 'space'."

Is that the "basic philosophical fact"? It is false.

Rational_One:

In view of the fact that this forum contains hundreds of threads, please give me a more specific pointer to the "Atheist" thread. What is its name? In which subforum is it? What is the date of the most recent entry (threads are sorted by that date)?

The universe is indeed unbounded. But there is no reason to believe that it is finite.

You said "The universe is neither expanding nor contracting, because that whole concept is absurd.".

As I said before -- the distances between clusters of galaxies are increasing. That is an established fact. And there is nothing absurd about it.

You said "The non-Euclidean geometry described by GR's field equations ... describes the curvature of the paths matter traverses.".

No. General Relativity holds that free-falling objects (objects not acted on by external forces other than gravity) follow geodesics which are orbits (lines in space-time) which are as straight as the curvature of space-time allows.

[HaloNoble6]

While I've tried, over and over, to explain in essential philosophical terms, how "nothing" or "empty space" is a relative concept, you simply reply with assertions or unnecessary details of physics. Why don't you tell me how one would form the concept "space" without ever referring to entities or their qualities?

[jrs]

Felipe:

I am sorry that I seem dense to you. But your assertions seem arbitrary and largely incomprehensible to me.

You asked "Why don't you tell me how one would form the concept 'space' without ever referring to entities or their qualities?".

Remember that existence is primary, not consciousness. That is, the way the world works is not dependent on how human beings think. So how we form concepts is irrelevant to the laws of physics.

Obviously, physicists have reached the current theories in some way or they would not have those theories. The history behind them is long and convoluted with many false starts and much back-tracking.

What one should ask is:

1. Can the theory be used to produce precise and consistent predictions about the phenomena of interest?

2. Are those predictions correct?

3. Can the calculations be done efficiently?

It is nice if the theory makes sense intuitively, but that is just icing on the cake.

Today's concept of space is derived from differential geometry, a branch of topology. It is a mathematical idealization of curved surfaces such as the surface of a globe.

[HaloNoble6]

And, as Necessary_Truths just implied, how you reach conclusions about the relationship between philosophy and science will be, and are, irrelevant until you understand concept-formation.

[Dominique]

Remember that existence is primary, not consciousness.  That is, the way the world works is not dependent on how human beings think.  So how we form concepts is irrelevant to the laws of physics.

Your main error is right here. It's another example of the mind-body dichotomy and what you are saying is essentially: How we understand the world is irrelevant to how we understand the world. This does not however imply primacy of conciousness. The two are corrollaries. Nature to be commanded, must be obeyed, but the the laws of physics had to be discovered by man, beginning with concept formation.

Obviously, physicists have reached the current theories in some way or they would not have those theories.

and that way is an epistemological system beginning with concept-formation.

What one should ask is:

1. Can the theory be used to produce precise and consistent predictions about the phenomena of interest?

2. Are those predictions correct?

3. Can the calculations be done efficiently?

How does one do this if they haven't first formed the concepts of "theory", "precise", "prediction", "phenomena" ? Concept formation is the basis of all subsequent knowledge. If there is an error in your method of concept-formation, than all your subsequent conclusions are likely to be false.

[jrs]

Felipe:

You said "... how you reach conclusions about the relationship between philosophy and science will be, and are, irrelevant until you understand concept-formation.".

Name one great scientist or mathematician who attributed his success to the application of formal epistemology.

I can just imagine "What about this idea? ... No, I cannot do that, because epistemology says that people do not think that way.".

That kind of excessive self-consciousness would cripple science.

Dominique:

You said "... what you are saying is essentially: How we understand the world is irrelevant to how we understand the world.".

Understanding (or more likely, MISunderstanding) at an abstract level how we understand the world is not necessary in order to understand the world. Although I will concede that it helps to be aware of the logical fallacies so that one can avoid them.

You said "... the the laws of physics had to be discovered by man, beginning with concept formation.".

It is one thing to form the concepts. It is another thing to force the formation of those concepts into the Procrustean bed of a theory of concept formation.

You said "Concept formation is the basis of all subsequent knowledge.".

Forming concepts is basic. Knowing epistemology is not.

How did Aristotle (or whoever did it) develop epistemology without a prior knowledge of epistemology?????

[Cole]

Something synonymous with "nothing" can be measured only with reference to the "something" which could fit into that "nothing."  But to speak of "space" or "nothing" as apart from "something" takes you outside the realm of measurability because you are no longer anchored to the concept of something.  I know, I think I sound vague, let me give this one more whirl.

"Space" must always presuppose "the something that could fit into that space."  Without this referent, one no longer is capable of measuring as such because it is entities that have finite qualities and quantities; and "space" does not qualify as an entity.  So, "space" itself is not "measurable" without reference to existents.  I hope this is clearer.

I'm still having some difficulty with this.

If space is the absence of any existents- absolute nothing- then how could forces exist in space that have an effect on matter? If space is non-existence, then how could space curve? If space cannot curve, then the General Theory of Relativity (which proves that the gravitational force between two objects is caused by the curvature of space between those objects, and not a push or pull from the objects themselves) is inaccurate. If this theory is inaccurate, then how do you explain the force of gravity? How can a force exist within something that is synonymous with "non-existence"?

[HaloNoble6]

I'm not familiar with GR, but saying that space is a relative concept does not preclude the possibility of things, such as forces, from traversing or existing or passing through there. I personally don't know the precise nature by which forces like gravity work. Newton had a hell of a lot of trouble when he first introduced the concept of "non-mechanical forces," forces that act at a distance. If you could shed light into how these forces work, I could perhaps answer your question.