The Logical Leap: Induction in Physics

[Philip Coates]

> In general relativity it is possible that different regions of curved space-time can move in opposite directions [DF]

1. There is no such thing as 'curved' space-time. Space is the place where things exist. It cannot itself literally be curved.

2. Moreover space and time are two different things. There is no such thing as space-time.

Edited July 27, 2010 by Philip Coates

[James Heaps-Nelson]

> In general relativity it is possible that different regions of curved space-time can move in opposite directions [DF]

1. There is no such thing as 'curved' space-time. Space is the place where things exist. It cannot itself literally be curved.

2. Moreover space and time are two different things. There is no such thing as space-time.

There are no such things as space and time that are universal to all reference frames. It is only an interrelationship of space and time that is invariant in special relativity.

Jim

Edited July 27, 2010 by James Heaps-Nelson

[BaalChatzaf]

> In general relativity it is possible that different regions of curved space-time can move in opposite directions [DF]

1. There is no such thing as 'curved' space-time. Space is the place where things exist. It cannot itself literally be curved.

2. Moreover space and time are two different things. There is no such thing as space-time.

Dead wrong on both counts. The apparent bending of light around the eclipsed sun is physical proof of the curvature of the space-time manifold. Gravitational lensing is a physical fact. Space and time are not the same but they are not separate either. The physics of gravitation and electrodynamics can only be understood when it is grasped that space and time are bound into a single manifold.

P.S. This is typical of why Objectivists do not produce first rate physicists, or mathematicians either. If you had a shred of decency you would turn in your GPS and go back to using parchment and Aristotelian logic.

Ba'al Chatzaf

Edited July 27, 2010 by BaalChatzaf

[James Heaps-Nelson]

> In general relativity it is possible that different regions of curved space-time can move in opposite directions [DF]

1. There is no such thing as 'curved' space-time. Space is the place where things exist. It cannot itself literally be curved.

2. Moreover space and time are two different things. There is no such thing as space-time.

Dead wrong on both counts. The apparent bending of light around the eclipsed sun is physical proof of the curvature of the space-time manifold. Gravitational lensing is a physical fact. Space and time are not the same but they are not separate either. The physics of gravitation and electrodynamics can only be understood when it is grasped that space and time are bound into a single manifold.

P.S. This is typical of why Objectivists do not produce first rate physicists, or mathematicians either. If you had a shred of decency you would turn in your GPS and go back to using parchment and Aristotelian logic.

Ba'al Chatzaf

Absolutely right, Ba'al. Einstein's theories are an outgrowth of Maxwell, not Newton. The physical basis of Einstein is accounting for the behavior of things like electrons, protons and light that can move at relativistic speeds and their behavior in a gravitational field. A universal theory of gravitation accounts for the behavior of fast moving bodies and very massive objects.

Jim

[George H. Smith]

> In general relativity it is possible that different regions of curved space-time can move in opposite directions [DF]

1. There is no such thing as 'curved' space-time. Space is the place where things exist. It cannot itself literally be curved.

2. Moreover space and time are two different things. There is no such thing as space-time.

Dead wrong on both counts. The apparent bending of light around the eclipsed sun is physical proof of the curvature of the space-time manifold. Gravitational lensing is a physical fact. Space and time are not the same but they are not separate either. The physics of gravitation and electrodynamics can only be understood when it is grasped that space and time are bound into a single manifold.

P.S. This is typical of why Objectivists do not produce first rate physicists, or mathematicians either. If you had a shred of decency you would turn in your GPS and go back to using parchment and Aristotelian logic.

Ba'al Chatzaf

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

[Xray]

Zeus and Thor as myths haven't stood up to scientific scrutiny either.

Neither has the God myth. The only difference with Zeus and Thor is that the latter no longer have many followers, but the number of believers in some supernatural power isn't a scientific argument either...

Indeed it isn't.

My epistemolocigal interest is focused on those groups of believers who present their belief as truth. For in that case, the onus probandi falls on them.

DF is a real physicist. I am just a reasonably well informed "fan" of the field. I have never played. I was trained as a mathematician and for many years did applied mathematics for a living.

Ba'al Chatzaf

From a website:

http://www.big-bang-theory.com/

According to the standard theory, our universe sprang into existence as "singularity" around 13.7 billion years ago. What is a "singularity" and where does it come from? Well, to be honest, we don't know for sure. Singularities are zones which defy our current understanding of physics. They are thought to exist at the core of "black holes." Black holes are areas of intense gravitational pressure. The pressure is thought to be so intense that finite matter is actually squished into infinite density (a mathematical concept which truly boggles the mind). These zones of infinite density are called "singularities." Our universe is thought to have begun as an infinitesimally small, infinitely hot, infinitely dense, something - a singularity. Where did it come from? We don't know. Why did it appear? We don't know.

The article speaks of the mathematical concept of infinite density boggling the mind.

Does it boggle the mind because infinite density is 'unimaginable' physically?

Edited July 27, 2010 by Xray

[BaalChatzaf]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

[George H. Smith]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

Okay, so give us an ultra precise definition of "space" and an ultra precise definition of "time."

If by "space" and "time" physicists mean something different than what people mean in ordinary discourse, then why do physicists use those words? Why didn't physicists choose other words, such as "ham" and "eggs," and redefine those words instead? Then they could explain, with ultra precision, the details of the ham and eggs manifold.

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

Ghs

[bmacwilliam]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

Okay, so give us an ultra precise definition of "space" and an ultra precise definition of "time."

If by "space" and "time" physicists mean something different than what people mean in ordinary discourse, then why do physicists use those words? Why didn't physicists choose other words, such as "ham" and "eggs," and redefine those words instead? Then they could explain, with ultra precision, the details of the ham and eggs manifold.

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

Ghs

I don't think that's an accurate assessment.

Physicists (uncle Al) discovered that time is not the cosmic absolute - the speed of light is. This has implications with respect to space and time that we have to accept that are counterintuitive. I don't think they "redefine" space or time they just refine them with a more precise description because our old description of time and space does not conform to reality.

Bob

[George H. Smith]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

Okay, so give us an ultra precise definition of "space" and an ultra precise definition of "time."

If by "space" and "time" physicists mean something different than what people mean in ordinary discourse, then why do physicists use those words? Why didn't physicists choose other words, such as "ham" and "eggs," and redefine those words instead? Then they could explain, with ultra precision, the details of the ham and eggs manifold.

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

Ghs

I don't think that's an accurate assessment.

Physicists (uncle Al) discovered that time is not the cosmic absolute - the speed of light is. This has implications with respect to space and time that we have to accept that are counterintuitive. I don't think they "redefine" space or time they just refine them with a more precise description because our old description of time and space does not conform to reality.

Bob

Suppose I say that Mortimer has a space between his two front teeth. Or that he couldn't find a parking space last night. Or that his new house has a lot of space. In these and similar usages of "space," we basically mean an unoccupied area.

So is the physicist, by using a more precise definition of "space," able to make the above statements more intelligible than they already are? If so, more intelligible to whom?

Ghs

[James Heaps-Nelson]

Have you considered the possibility that physicists use the words "space" and "time" with different meanings than we find in ordinary language?

Ghs

Indeed they do and they define their usage with ultra precision. Which is why physics succeeds and philosophy fails (among other reasons).

Ba'al Chatzaf

Okay, so give us an ultra precise definition of "space" and an ultra precise definition of "time."

If by "space" and "time" physicists mean something different than what people mean in ordinary discourse, then why do physicists use those words? Why didn't physicists choose other words, such as "ham" and "eggs," and redefine those words instead? Then they could explain, with ultra precision, the details of the ham and eggs manifold.

If you are going to use stipulative definitions to change the meaning of words, then what difference does it make which words you use?

Ghs

I don't think that's an accurate assessment.

Physicists (uncle Al) discovered that time is not the cosmic absolute - the speed of light is. This has implications with respect to space and time that we have to accept that are counterintuitive. I don't think they "redefine" space or time they just refine them with a more precise description because our old description of time and space does not conform to reality.

Bob

Suppose I say that Mortimer has a space between his two front teeth. Or that he couldn't find a parking space last night. Or that his new house has a lot of space. In these and similar usages of "space," we basically mean an unoccupied area.

So is the physicist, by using a more precise definition of "space," able to make the above statements more intelligible than they already are? If so, more intelligible to whom?

Ghs

Only if Mortimer is approaching his parking space or his house at > 10% of the speed of light :-). In that case, I think the physicist would have to bow to Mortimer's abilities.

Jim

[Philip Coates]

> The apparent bending of light around the eclipsed sun is physical proof of the curvature of the space-time manifold. [baal]

No, it's proof that -light- is bent.

Edited July 27, 2010 by Philip Coates

[BaalChatzaf]

> The apparent bending of light around the eclipsed sun is physical proof of the curvature of the space-time manifold. [baal]

No, it's proof that -light- is bent.

Yes. Light follows the path of shortest length on the 4-d space-time manifold. The manifold is bent and light follows it in order to take the shortest distance.

When you walk on an essentially spherical surface you follow the shortest distance path which are great circle arcs. Light does somewhat the same thing on the 4-d space-time manifold.

Ba'al Chatzaf

[kiaer.ts]

True, or false, Phil? A triangle can have internal angles which add up to more than 180°?

[BaalChatzaf]

True, or false, Phil? A triangle can have internal angles which add up to more than 180°?

What is the underlying space?

Ba'al Chatzaf

[Philip Coates]

It's not a space. It's a surface. As in Euclidean or non-Euclidean geometry.

[kiaer.ts]

Answer the question, Phil.

[Brant Gaede]

What triangle are you talking about Ted? The one in which the angles add up to only 180 degrees or the one that adds up to more than 180 degrees?

--Brant

[BaalChatzaf]

It's not a space. It's a surface. As in Euclidean or non-Euclidean geometry.

A surface is a topological metric space. The term "space" in mathematics refers to an abstract structure. This is clearly an abstract extension of our experience with immediately perceived space, the kind in which we wave our arms about.

Modern physics is very Platonic in its approach. It treats abstract mathematical objects as either real things or things which resemble real things. In the last analysis, Plato and Pythagoras won and Aristotle didn't. Modern physical science assumes abstract entities in order to explain and describe things that we can perceive with our senses.

Ba'al Chatzaf

[rhartford]

I'm a little suprised there are "flat-spacers" on this list, but the evidence against flat-space is not yet as strong, for the general public, as the evidence against a flat-earth. So, it is understandable that someone could be a "flat-spacer," in contrast to the absurdity of being a "flat-earther."

The theory of General Relativity is mathematically, physically, and philosophically beautiful. It's success in explaining complex astronomical observations is extraordinary. It is "the only game in town" for explaining how existence can have a finite volume and yet have no boundaries, a solution to Einstein's equation that appeals to me as both a physicist and an amateur philosopher. That particular solution describes a finite size for Existence with no "outside." The Existence described is all there is and its characterisitics are finite.

Einstein's explantion of the way that the theory of General Relativity uses the distribution of matter and energy as cause of the spatial and temporal nature of existence, and uses the spatial and temporal nature of existence to explain the motion of matter is truly an astonishing result and a testament to the power of the human mind. I am not an expert in relativity, but I know enough to consider it philosphically beautiful.

[Philip Coates]

Ted, see my post #291. The answer is not 180 if you're talking non Euclidean geometry, non-flat curved surface like on the surface of a sphere.

[George H. Smith]

I'm a little surprised there are "flat-spacers" on this list, but the evidence against flat-space is not yet as strong, for the general public, as the evidence against a flat-earth. So, it is understandable that someone could be a "flat-spacer," in contrast to the absurdity of being a "flat-earther."

For me, this is not a question of whether space is flat or curved. Rather, it is an issue of whether or not we commit a category mistake in attributing any such attributes to space. Only an existent can have attributes, and I daresay that in most normal discourse we don't think of space as something with this kind of ontological status.

Suppose every existent in the universe, whether in the form of matter or energy, were to disappear. What would be left? By the terms of this hypothetical, we would have to say "nothing." Another way of putting this, for many people, would be to say, "Only empty space would remain."

So would a physicist agree with this way of speaking? Or would he argue that space itself is an existent and not merely "nothing"? If he were to say this, then it makes sense to attribute characteristics to space, such as calling it "curved." Otherwise, however, it makes no more sense to call space "curved" than it does to call it "green" or "temperamental."

I don't say this to cast doubt on the theory of General Relativity. Rather, my point is that physicists sometimes use words in a careless way. They have their own technical vocabulary, one that frequently employs operational definitions that are accepted so long as they yield fruitful results. So far, so good. The problem arises when these operational definitions, which are typically mathematical in character, are expressed in the language of everyday life.

Physicists, like everyone else, are obliged to make sense when they use conventional language. They are not the high priests of the modern world with a privileged knowledge of "ultimate reality" that exempts them from the responsibility of speaking intelligibly when explaining their results to laypersons.

In Social Sciences as Sorcery, Stanislav Andreski tells the following story about the great Swiss mathematician and physicist Leonhard Euler. While visiting the court of Catherine II of Russia, Euler got into an argument with some religious skeptics. Euler called for a blackboard, claiming he could prove the existence of God, and on it he wrote a mathematical formula with the conclusion, "therefore God exists." Andreski (p. 127) comments:

Unable to dispute the relevance of the formula which they did not understand, and unwilling to confess their ignorance, the literati accepted his argument. Owing to the continuing widespread ignorance of this subject, the utility of mathematical formulae for the purpose of blinding people with science, eliciting their respect and foisting upon them unwarranted propositions, has hardly diminished....

Ghs

[Brant Gaede]

I think Newton and Euler are considered to be the two greatest mathematicians of all time. Considering how far back in time he was and the recent discovery that he invented a calculus, maybe Archimedes should get a real big nod too.

--Brant

can't evaluate these guys personally

[kiaer.ts]

Ted, see my post #291. The answer is not 180 if you're talking non Euclidean geometry, non-flat curved surface like on the surface of a sphere.

Yes, and since the same answer applies in the space around a massive object, why would you not call that space curved in a higher dimension, just as you call the two dimensional surface of the earth curved in a third dimension?

[Ellen Stuttle]

Suppose every existent in the universe, whether in the form of matter or energy, were to disappear. What would be left? By the terms of this hypothetical, we would have to say "nothing." Another way of putting this, for many people, would be to say, "Only empty space would remain."

I would call *that* careless use of language, equating "nothing" with "empty space," as if "space" is being thought of as a container into which stuff is put. If there's "nothing," there isn't "space" either.

"Space" in "space-time" is thought of as a something, an existent, not merely a measurement of relationships between existents.

Physicists, like everyone else, are obliged to make sense when they use conventional language. They are not the high priests of the modern world with a privileged knowledge of "ultimate reality" that exempts them from the responsibility of speaking intelligibly when explaining their results to laypersons.

Is the obligation like a categorical imperative? Are physicists permitted to use "mass" with a technical meaning which isn't the conventional meaning? "Energy"? "Weight"? Etc. Probably almost all, if not all, the terms used in physics are also used with different meanings in common parlance. And it's not as if there aren't sources where laypersons can find explanations of the physics meaning of terminology. The meanings aren't being hidden as if by a priesthood keeping secrets.

Ellen