Is space nothing?


jts

Recommended Posts

My beef with Rand's formulation, treating the universe and time as if they were distinct, is that this implies existence can be made up of things that do not depend on belonging to the universe.

Hi Michael,

I don't think that Rand's view was that the universe and space or time were distinct. That is the position she was arguing against. And, I don't think it is a straw man argument. For example, religious apologists will sometimes posit a question such as, "What came before the universe?" Their answer, of course, is God. But, if time refers only to things that exist, e.g., the duration of a soccer game, then the question makes no sense. The question requires time to exist independently of the universe.

BTW, I don't think it is unnatural to think of space and time as existing independently of everything else. One can imagine an infinite Cartesian coordinate frame describing the positions of the stars and planets. But, if there is a finite number of such objects, then the size of the known universe is bounded, but, one can imagine space itself extending forever. It is a natural abstraction. The measurement is omitted, meaning that it can be any value. That is especially relevant to a closed universe theory. If a ray of light eventually returns to its point of origin due to the curvature of space-time, then the universe is closed and finite. But, the abstraction of an infinite space remains and it is natural to ask what is outside of the universe. Does the universe exist within some higher dimensional, unbounded embedding space? That's a rhetorical question. The point is that an infinite Cartesian coordinate frame is a natural abstraction.

Darrell

Link to comment
Share on other sites

  • Replies 79
  • Created
  • Last Reply

Top Posters In This Topic

Does this mean Objectivism says space is nothing?

From Ayn Rand Lexicon:

“Space,” like “time,” is a relational concept. It does not designate an entity, but a relationship, which exists only within the universe. The universe is not in space any more than it is in time. To be “in a position” means to have a certain relationship to the boundary of some container. E.g., you are in New York: there is a point of the earth’s surface on which you stand—that’s your spatial position: your relation to this point. All it means to say “There is space between two objects” is that they occupy different positions. In this case, you are focusing on two relationships—the relationship of one entity to its container and of another to its container—simultaneously.

Let's do a little thought experiment. Imagine an object spinning in an otherwise empty cosmos. What is it spinning in relation to? There is nothing else. Does it even make sense to say that it is spinning? If it is spinning, then it is experiencing centrifugal force. The centrifugal force would be proof that it is spinning and the only possible proof of spinning in an otherwise empty cosmos. If space is nothing, as Peikoff seems to be saying in the ARL quote, then how is spinning (as proved by centrifugal force) possible? This thought experiment seems to suggest that space is something and not nothing. The object is spinning in relation to space.

It could be that rotation is relative, but it could be that it is absolute. Einstein theorized that inertial frames of reference are indistinguishable. But, a rotating object is not an inertial frame of reference. Every point on it, other than the point at the center of rotation is constantly accelerating.

Let's say the universe was not empty, but that there was a rotating object out there somewhere. One could say that it is rotating relative to the "fixed stars" as cosmologists like to say. But, what if the stars weren't fixed. What if some were moving with appreciable velocity as seen from the rotating object. Then, the speed of rotation, relative to those stars might appear to be different. However, the centripetal acceleration and apparent centrifugal force would be the same, showing that it is the absolute rate of rotation, not the relative rate of rotation that matters.

Of course, you could use that as more evidence for the existence of fixed space, but there are other experiments which appear to contradict the notion of fixed space. For example, the fact the speed of light appears to be the same in every inertial reference frame, even if that frame is moving with high velocity.

Darrell

Link to comment
Share on other sites

I don't think that Rand's view was that the universe and space or time were distinct. That is the position she was arguing against.

Darrell,

I'm having a run of poor expression. I got too far out on a tangent in my head and lost sight of the obvious. I don't mean Rand held this as her own position. I meant that she was arguing against those who thought that way, meaning that it was common for people to think that way to her. And that I did not know of anyone who thought that way.

Reworded, it would probably be better as: My beef with Rand's formulation for criticizing others, treating the universe and time as if they were distinct, is that this implies existence can be made up of things that do not depend on belonging to the universe, and I don't know of anyone (outside of the God argument) who thinks that way.

BTW, I don't think it is unnatural to think of space and time as existing independently of everything else.

Space and time existing independently of the universe? Or just everything else within the universe?

If the universe itself, I now know one who thinks that way.

:)

Michael

Link to comment
Share on other sites

If one believes that there may exist, or may have existed, or may at some future point existed, *universes* either parallel to this one, or existing prior to or after the death of this one....

then it would be useful to draw a distinction between the "universe" and "existence".

Kacy,

I agree we can speculate and artificially (abstractly only) split concepts from their referents, but I don't know of anyone who actually believes in parallel universes except a small handful of QM geeks. And their referents are solely made up of mathematical speculations, not observed reality, so they offer nothing but a different form of religious faith.

In other words, we all know what wings are and what pigs are. So it's easy to separate artificially (abstractly only) each concept from its referents in reality and join them in our minds. Thus we get flying pigs. But I don't know of anyone who actually believes in flying pigs as existing in reality.

(Besides, it's Obama's fault.)

:)

Michael

Link to comment
Share on other sites

David Harriman, in The Logical Leap, succinctly describes Newton's view of absolute space and time.

This is in a passage in which he distorts Newton's thinking process and both subtly and obviously mispresents the issue of Einstein's versus Newton's views.

Nonetheless, I think that this bit, just taken by itself, is clear on Newton's idea of absolute space and time:

The Logical Leap, pg. 148

Newton [thought of absolute space and time] as existents independent of bodies, rather than as relationships among bodies. Thus he viewed [absolute] space as an infinite cosmic backdrop that exists independent of the bodies placed in it, and he claimed that this backdrop has real physical effects on the bodies that accelerate with respect to it.

Further on in the same passage, Harriman states:

The Logical Leap, pp. 148-49

The correct relational view dates back to Aristotle, who treated space as a sum of places and explained that the concept "place" refers to a relationship among bodies.

Ellen

Link to comment
Share on other sites

physical effects on the bodies that accelerate with respect to it.

Further on in the same passage, Harriman states:

The Logical Leap, pp. 148-49

The correct relational view dates back to Aristotle, who treated space as a sum of places and explained that the concept "place" refers to a relationship among bodies.

Ellen

Aristotle got motion completely wrong. He was void on the concept of inertia. He believed all motions had to be maintained by a force. Aristotle's mistaken ideas of motion retarded the development of proper dynamics for 1500 years.

Aristotle never checked. A kid could have disproved his notion that heavier bodies fall at a speed proportional to their weight in no time flat.

Ba'al Chatzaf

Link to comment
Share on other sites

btw - On Rand's "little stuff," leave it to Peikoff to come up with "puffs of existence." :)

Peikoff's puffs doesn't refer to the same issue as Rand's "little stuff." The latter refers to there being no absolute vacuum, no "empty" space.

The "puffs" is a hypothetical example Peikoff used when he was explaining that the Objectivist position on primary/secondary qualities had been changed as a result of some conversations between him and Rand, the new position was that all qualities are relational. Peikoff illustrated by saying, suppose that the ultimate nature of reality was some sort of "puffs," it would still be the case that the relationship between our sensory apparatus and what we perceive takes the form in which we perceive.

I think he discusses the "puffs" in OPAR.

Also, just a reminder - Tony already pointed this out in post #9 - the Lexicon entry quoted in the opening post is from Peikoff's 1976 course on the philosophy of Objectivism, not from Rand. Presumably, the statement had her approval, since she was in attendance, but the wording is Peikoff's.

Ellen

Link to comment
Share on other sites

Aristotle got motion completely wrong. He was void on the concept of inertia. He believed all motions had to be maintained by a force. Aristotle's mistaken ideas of motion retarded the development of proper dynamics for 1500 years.

Aristotle never checked. A kid could have disproved his notion that heavier bodies fall at a speed proportional to their weight in no time flat.

Ba'al Chatzaf

Hi, Mr. Mantrist.

Do you have any idea how often you've repeated that particular one of your mantras?

Ellen

Link to comment
Share on other sites

Aristotle [...] was void on the concept of inertia.

Speaking of "the concept of inertia," however, Newton didn't mean by "inertia" what we mean by it. Our wording " an inertial frame" isn't the wording he used.

This change in meaning is among the issues on which McCaskey criticized The Logical Leap. (McCaskey circumspectly only addressed certain issues instead of going for the jugular, but the implications of his critiques weren't lost on Peikoff.)

Ellen

Link to comment
Share on other sites

Aristotle [...] was void on the concept of inertia.

Speaking of "the concept of inertia," however, Newton didn't mean by "inertia" what we mean by it. Our wording " an inertial frame" isn't the wording he used.

This change in meaning is among the issues on which McCaskey criticized The Logical Leap. (McCaskey circumspectly only addressed certain issues instead of going for the jugular, but the implications of his critiques weren't lost on Peikoff.)

Ellen

Look at Newton's First Law of Motion. He means what everyone else means. A body moving through space with a net zero force acting on it will move in a straight line at uniform speed or it will be at rest. Galileo also made the same observation, but he did not have the fancy mathematics that Newton invented.

One knows there is a force (not net zero) acting on a body if its momentum changes over time. That means either its speed or its direction changes (or both).

The concept of frame was perfect one hundred years after the publication of Principia.

Aristotle got motion wrong in just about every respect. He believed nothing moved unless a force acted on it. zzzzzzt ..... wrong!

It occurs to me that if Greece had proper winters and the Greeks developed ice hockey, maybe Aristotle would have caught on to inertia. But he lived in a World of Friction. It is only in a world with smooth enough surfaces that one can imagine a body sliding or floating in a uniform manner with no further forces acting on it. Alas, Athens was just in the wrong climatic zone.

Link to comment
Share on other sites

Regarding Newton and "inertia," the (current) Wikipedia article is actually good on that issue:

link

[bold emphasis added]

[....]Isaac Newton defined inertia as his first law in his Philosophiæ Naturalis Principia Mathematica, which states:[1]

The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.

[....]

Nevertheless, despite defining the concept so elegantly in his laws of motion, even Newton did not actually use the term "inertia" to refer to his First Law. In fact, Newton originally viewed the phenomenon he described in his First Law of Motion as being caused by "innate forces" inherent in matter, which resisted any acceleration. Given this perspective, and borrowing from Kepler, Newton actually attributed the term "inertia" to mean "the innate force possessed by an object which resists changes in motion"; thus Newton defined "inertia" to mean the cause of the phenomenon, rather than the phenomenon itself. However, Newton's original ideas of "innate resistive force" were ultimately problematic for a variety of reasons, and thus most physicists no longer think in these terms. As no alternate mechanism has been readily accepted, and it is now generally accepted that there may not be one which we can know, the term "inertia" has come to mean simply the phenomenon itself, rather than any inherent mechanism. Thus, ultimately, "inertia" in modern classical physics has come to be a name for the same phenomenon described by Newton's First Law of Motion, and the two concepts are now considered to be equivalent.

Ellen

Link to comment
Share on other sites

A bit more from Cohen on the inertia issue:

I. Bernard Cohen's Guide to Newton's Principia, in the volume referenced post above - see.

pg. 96

Today's reader will also be struck by the fact that Newton uses the word "force" in relation to "inertia" ("vis inertiae"), although - as Newton is at pains to explain - this is an internal force and not the kind of force which (according to the second law) acts externally to change a body's state of rest or motion.

pg. 98

[...] by introducing the "force" of inertia rather than simply "inertia" as a property of matter, Newton (if only on an unconscious or psychological level) has not fully abandoned the ancient notion that every motion must require a "mover" or some kind of moving force, even if a very special kind of internal force.

Ellen

Link to comment
Share on other sites

Regarding Newton and "inertia," the (current) Wikipedia article is actually good on that issue:

link

[bold emphasis added]

[....]Isaac Newton defined inertia as his first law in his Philosophiæ Naturalis Principia Mathematica, which states:[1]

The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.

[....]

Nevertheless, despite defining the concept so elegantly in his laws of motion, even Newton did not actually use the term "inertia" to refer to his First Law. In fact, Newton originally viewed the phenomenon he described in his First Law of Motion as being caused by "innate forces" inherent in matter, which resisted any acceleration. Given this perspective, and borrowing from Kepler, Newton actually attributed the term "inertia" to mean "the innate force possessed by an object which resists changes in motion"; thus Newton defined "inertia" to mean the cause of the phenomenon, rather than the phenomenon itself. However, Newton's original ideas of "innate resistive force" were ultimately problematic for a variety of reasons, and thus most physicists no longer think in these terms. As no alternate mechanism has been readily accepted, and it is now generally accepted that there may not be one which we can know, the term "inertia" has come to mean simply the phenomenon itself, rather than any inherent mechanism. Thus, ultimately, "inertia" in modern classical physics has come to be a name for the same phenomenon described by Newton's First Law of Motion, and the two concepts are now considered to be equivalent.

Ellen

Although I used the phrase, "inertial frame of reference," I agree that the concept of inertia is extraneous in modern physics (or even the modern view of classical physics). Instead, the quality of an object "which resists changes in motion" is just its mass. So, sometimes the words "mass" and "inertia" are used interchangeably.

The one place that the word inertia still gets some play is in rotational kinematics. Just as Newton's law says F = ma or force equals mass times acceleration, in rotational kinematics the equivalent equation is torque equals rotational-inertia times angular-acceleration or tau = I * alpha. But, although the word "inertia" is used, it is not viewed as a force as was common before Newton's time. It is just a quantity computed from the geometric arrangement of mass within a body. BTW, I would suppose that Newton's use of "inertia" as an intrinsic force was probably a hold-over from Aristotle's way of thinking.

Darrell

Link to comment
Share on other sites

BTW, I would suppose that Newton's use of "inertia" as an intrinsic force was probably a hold-over from Aristotle's way of thinking.

Darrell,

We posted almost simultaneously.

Re the "hold-over," see post #38, which you might have missed because of its coming in while you were posting #39.

Ellen

Link to comment
Share on other sites

I don't think that Rand's view was that the universe and space or time were distinct. That is the position she was arguing against.

Darrell,

I'm having a run of poor expression. I got too far out on a tangent in my head and lost sight of the obvious. I don't mean Rand held this as her own position. I meant that she was arguing against those who thought that way, meaning that it was common for people to think that way to her. And that I did not know of anyone who thought that way.

Reworded, it would probably be better as: My beef with Rand's formulation for criticizing others, treating the universe and time as if they were distinct, is that this implies existence can be made up of things that do not depend on belonging to the universe, and I don't know of anyone (outside of the God argument) who thinks that way.

BTW, I don't think it is unnatural to think of space and time as existing independently of everything else.

Space and time existing independently of the universe? Or just everything else within the universe?

If the universe itself, I now know one who thinks that way.

:smile:

Michael

Thanks for clarifying. I wasn't sure where you were going with that line of thought.

As for my view, I'm not saying that I believe space and time exist independently of the universe. I am more inclined to believe they are purely relational quantities. At least, that is what we are taught in physics. That was Einstein's view and is the only vantage point from which his Theory of Special Relativity makes sense. That is, if the rate at which you see other people's clocks running and the lengths of their rulers depends upon your speed relative to them, then time and space are different in every reference frame. They are not absolute. They don't exist. They are purely relational quantities.

I'm not sure I completely buy Einstein's argument, despite the strong experimental evidence for the conclusions of his theory. For one thing, it is impossible to find completely empty space. There is always a little "dust" even if it is very low density and that dust has a velocity which may be taken to be zero on average. The consequence is that if you fly at a high velocity through space, you can pick up the dust. Some people have suggested picking up hydrogen molecules and using them as fuel. It's not that hard to pick up enough hydrogen if you're travelling at near the speed of light. But, that seems to imply a preferred frame of reference, the frame in which the space dust is at rest, so to speak. Or, one can think of a frame in which the "fixed stars" are pretty much at rest --- probably the same frame as the one in which the space dust is at rest. Of course, the preferred frame will tend to change over intergalactic distances since the galaxies are all racing away from us and each other --- at least that's what the evidence seems to show --- due to the red shift of the light from them. But, there would certainly seem to be consequences to travelling at a high rate of speed relative to the nearest stars or galaxies. One's experience will change in an absolute way, not just relatively.

So, at any rate, space and time may be thought of as purely relational quantities, but at least locally, there seems to be preferred reference frame possibly created by the mass present in the galactic neighborhood.

Darrell

Link to comment
Share on other sites

BTW, I would suppose that Newton's use of "inertia" as an intrinsic force was probably a hold-over from Aristotle's way of thinking.

Darrell,

We posted almost simultaneously.

Re the "hold-over," see post #38, which you might have missed because of its coming in while you were posting #39.

Ellen

Hi Ellen,

Yes, I noticed that and would have referenced your post #38 if I had seen it before I hit the "post" button. Somehow, you managed to slide in there just before me. Oh well, it's all good. :)

Darrell

Link to comment
Share on other sites

Aristotle [...] was void on the concept of inertia.

Speaking of "the concept of inertia," however, Newton didn't mean by "inertia" what we mean by it. Our wording " an inertial frame" isn't the wording he used.

Newton meant the property of a massive body to keep on moving the way it was moving in a straight line if no net force is acting on it, or to remain at rest if it was at rest if not net force is acting on it. As I mention, Aristotle believed that is something were moving then something must be pushing (or pulling) it. It was this error that was at the heart of Aristotle's ideas of motion.

Ba'al Chatzaf

Link to comment
Share on other sites

Newton meant the property of a massive body to keep on moving the way it was moving in a straight line if no net force is acting on it, or to remain at rest if it was at rest if not net force is acting on it.

Which property he called "vis" - "vis inertiae." Is "inertia" thought of as any sort of "force" in modern physics?

Ellen

Link to comment
Share on other sites

Newton meant the property of a massive body to keep on moving the way it was moving in a straight line if no net force is acting on it, or to remain at rest if it was at rest if not net force is acting on it.

Which property he called "vis" - "vis inertiae." Is "inertia" thought of as any sort of "force" in modern physics?

Ellen

Yes and no. If bodies have mass it is because of the intermediation of a boson.

But go back to Newton and the Principia. When he proved that in a central force field (a field of centripital force vectors all pointing to one source) he did some vector addition. One -force- vector to the central source (this is the cenrtipital force) and one inertia vector that is tangential to the body's motion and applied at the same position as the centripital force vector. The resultant (an infinitesimal by the way) produces a motion such that the area swept at by the centripital force vectors is equal for equal times.

So Newton is treating inertia as a force vector. But the vis inertea (inertial force) is produced by the body itself rather by an external body. Unlike a "real" force which produces a reaction force (Newton's third law) the vis inertea has no reaction force produced by itself.

This is a very subtle thing. It took a genius like Newton to manage this trick. By the way, he initially thought that the motion of body was the resulting of centrifugal force and centripital force but (get this now!) Robert Hooke talked him out of this error. And that is how Newton finally accounted for Kepler's three laws and figured out how the tides worked (which Galileo never did. Mr. G's "theory" of the tides, was bogus plus)

Ba'al Chatzaf

Link to comment
Share on other sites

Newton meant the property of a massive body to keep on moving the way it was moving in a straight line if no net force is acting on it, or to remain at rest if it was at rest if not net force is acting on it.

Which property he called "vis" - "vis inertiae." Is "inertia" thought of as any sort of "force" in modern physics?

Ellen

Yes and no. If bodies have mass it is because of the intermediation of a boson.

But go back to Newton and the Principia. When he proved that in a central force field (a field of centripital force vectors all pointing to one source) he did some vector addition. One -force- vector to the central source (this is the cenrtipital force) and one inertia vector that is tangential to the body's motion and applied at the same position as the centripital force vector. The resultant (an infinitesimal by the way) produces a motion such that the area swept at by the centripital force vectors is equal for equal times.

So Newton is treating inertia as a force vector. But the vis inertea (inertial force) is produced by the body itself rather by an external body. Unlike a "real" force which produces a reaction force (Newton's third law) the vis inertea has no reaction force produced by itself.

This is a very subtle thing. It took a genius like Newton to manage this trick. By the way, he initially thought that the motion of body was the resulting of centrifugal force and centripital force but (get this now!) Robert Hooke talked him out of this error. And that is how Newton finally accounted for Kepler's three laws and figured out how the tides worked (which Galileo never did. Mr. G's "theory" of the tides, was bogus plus)

Ba'al Chatzaf

I have a hard time understanding these things as you've explained them here, which is not a complaint, but I wonder if Newton had simply started with things moving as a given he wouldn't have had such a difficult thing as he did figuring them out.

--Brant

Link to comment
Share on other sites

  • 4 months later...

Thanks for clarifying. I wasn't sure where you were going with that line of thought.

As for my view, I'm not saying that I believe space and time exist independently of the universe. I am more inclined to believe they are purely relational quantities. At least, that is what we are taught in physics. That was Einstein's view and is the only vantage point from which his Theory of Special Relativity makes sense. That is, if the rate at which you see other people's clocks running and the lengths of their rulers depends upon your speed relative to them, then time and space are different in every reference frame. They are not absolute. They don't exist. They are purely relational quantities.

I don't think it's a good idea to conclude that just because something is observer dependent that it doesn't exist. For one thing, the measurements that each observer makes are objective facts and any observer can deduce the measurements of any other observer for a given system using the Poincare group. That this is possible is not a trivial fact. Reality could well have been such that observers cannot deduce each others' measurements, but it turns out that they can.

I'm not sure I completely buy Einstein's argument, despite the strong experimental evidence for the conclusions of his theory. For one thing, it is impossible to find completely empty space. There is always a little "dust" even if it is very low density and that dust has a velocity which may be taken to be zero on average. The consequence is that if you fly at a high velocity through space, you can pick up the dust. Some people have suggested picking up hydrogen molecules and using them as fuel. It's not that hard to pick up enough hydrogen if you're travelling at near the speed of light. But, that seems to imply a preferred frame of reference, the frame in which the space dust is at rest, so to speak. Or, one can think of a frame in which the "fixed stars" are pretty much at rest --- probably the same frame as the one in which the space dust is at rest. Of course, the preferred frame will tend to change over intergalactic distances since the galaxies are all racing away from us and each other --- at least that's what the evidence seems to show --- due to the red shift of the light from them. But, there would certainly seem to be consequences to travelling at a high rate of speed relative to the nearest stars or galaxies. One's experience will change in an absolute way, not just relatively.

So, at any rate, space and time may be thought of as purely relational quantities, but at least locally, there seems to be preferred reference frame possibly created by the mass present in the galactic neighborhood.

Darrell

A "preferred frame" does not refer to a merely convenient frame, which is the sort of frame you're describing here. A preferred frame is a frame in which the laws of physics would take on a simpler form than in other frames. In SR, there is no such frame, whether space is completely empty or filled with dust.

Link to comment
Share on other sites

Yes. Space is a sum of places.

"Imagine an object spinning in an otherwise empty cosmos."

Yet we don't live in an empty cosmos. A spinning object is always spinning in relation to something. Secondly, let's say it was ordinary matter that we know experiences centrifigul force, it would be made of atoms, and those atoms would be moving in relation to one another. If it was one atom, it'd be changing in relation to the protons and neutrons in the nucleus. If it was a single proton, it would be moving in relationship with the quarks. Perhaps spinning quarks don't undergo centrifugal force for some reason. Maybe it's a force derived from the nature of having complex matter or from having a universe full of stuff. Your thought experiment is assuming that the object would behave the same as in a full universe, in the same way complex matter does. It's meaningless. You can't say it would or wouldn't. What is your single object? Perhaps the universe is such that a single object is an impossibility.

Inventing a non-existent fantasy doesn't do much to explain the universe.

Link to comment
Share on other sites

Completely empty space means there is no space. Something in space defines a space but its existence is purely epistemological. You can't move space around or modify it in any way. An expanding universe is not expanding into space it is creating space which it only a measurement of distance and what's in it. Time is just a measurement of motion--of something. No matter what you do with space, time and space-time those are all and only in your head.

--Brant

the layman strikes, can't swim, blub, blub, blub

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now