owl

Me: Swansont: TAR2: By “the world” I mean the cosmos and all of its parts, or physical reality in general. As a retired psychologist I well know that everyone experiences "the world" in their own unique way.... the subjective experience of the world. Some deny that “the world” exists intrinsically, objectively, ‘all by itself’ independent of the subjective experience of it. They are called subjective idealists in the realm of philosophy. Others insist that the above is not true... that “the world” does in fact exist with all of its intrinsic properties, distances between objects, etc., independent of how it is observed or subjectively experienced. They are called realists or naturalists. They insist that the world (and all physical relationships) is real ‘all by itself.’ So, along comes the part of relativity theory (SR) that says “the world” is as it is observed/measured from whatever frame of reference (FOR), and there is no “preferred FOR.” So, it either changes with every FOR from which it is observed (no intrinsic properties), or it doesn't change with every possible FOR, but we can not know which FOR yields an accurate description or measurement (all FORs being equally valid.) I have argued that the claim, "the world is as it is observed/measured from whatever frame of reference" is a form of subjective idealism substituting FOR for “subjective”, even though a FOR can be an abstract, theoretical perspective not requiring a personal observer. And, of course there is a philosophical difference between the “either” and the “or” positions above. The ‘either’ would be strict idealism where the world has no objective reality of its own, and perception or subjective experience is all there is. The ‘or’ position would be a form material agnosticism in which epistemology (science in particular) can not know the world as it is. The specific schools of thought get complicated*. I would recommend a search and study of objective idealism, subjective idealism, realism, and naturalism. *The complications arise from various mixes of ontology ( philosophy of what exists) and epistemology (how we know what exists.) I obviously subscribe to naturalism/realism and believe that the ‘the world’ exists as it is independent of perception/measurement. Empirical science then develops the epistemology of how we know ‘the world as it is.' I have been very specific about the “preferred frame of reference” (at rest with object) for investigating any given object-as-it-is or distances between objects.

Late entry, just feeling like summing up this evening. Realism says that the world is as it is, intrinsically, without our help. Idealism says that the world is as we see it. Take your pick. Science at its best investigates what the world is, as it is and how it functions on its own, as if it were not being measured. They call it objectivity in high school science classes. Relativity now seems to claim that there is no "real world," because all different frames of reference define reality differently from each and every perspective. This again introduces the basic question of how best to investigate the world. If interested in this question please visit (or revisit) my arguments in this thread for an at-rest frame with the object of investigation.

Huh? did you even read my last long winded post with its philosophical afterthought in summary of realism vs idealism? There is no reality independent of how we see it? So this makes us observers the creators of reality and it morphs drastically with how we view it? Good grief! You really know how to hurt a guy's feelings, calling me an idealist after all the explanation repeated throughout this thread about the difference between idealism and realism! My evil plan is to debunk the nonsense of length contraction and time dilation by all those arguments above. My favorite three examples, yet again show that all the evidence points to a precisely measured and shaped nearly spherical Earth (no evidence for one with a 1000 mile diameter), that distance between Sun and Earth (being intrinsically real bodies with actual, real cosmos distance between them) does not vary with the FOR from which it is measured, and that the meter rod does not actually shrink to 12 cm just because it might be seen as such from an extreme velocity FOR. I agreed that different FORs see distances differently and that lightspeed is constant. It can not be pushed faster by a speeding laser or flashlight, for instance. I explained how that makes sense to me. We seem to be talking "past each other" about realism and idealism. I can live with "evil" and deluded idealists; but I think they make "bad" scientists who believe that their sacrosanct "no preferred FOR" makes the cosmos dependent on their perception of it. ...That there is no intrinsically real cosmos with objective properties in and of itself (and all its parts) until granted by its Creators, the Observers, each in their own little FOR. ('The poly/pan-theism of relativity.' A good title for a realist's paper/blog.)

(a little out of phase here with my late editing...) Yes, it is abundantly clear! Is it clear to you that reality*, according to realism (*the actual distance between things and the photons they emit) does not depend on how it is measured from individual frames of reference? You say, "there is a distance between two objects." Idealism says that distances between objects does depend on from where and at what velocity those distances are observed, i.e., all sizes, shapes, lengths/distances depend on how they are perceived... the world has no reality of its own independent of how we all important observers see it. Quite an observer centered take on the world/universe, as its reality and properties depend on how we observe them! There is a distance between sun and earth, for instance. Observing that distance from extreme frames of reference does not make that distance change. If you think so you are an idealist and, again, I will rest my case. This is a philosophical afterthought which turned into a kind of summary of this thread's topic. (Please excuse some repetition of the point of my last post.) It's too bad that there are no philosophers of science here, or scientists with a grasp of this philosophical distinction (realism vs idealism.) The theory of length contraction and time dilation (reciprocals as I understand them) depends on an observer (frame of reference) dependent "reality" as if the world/cosmos had no intrinsic reality of its own, like shapes of cosmic bodies, distances between them, lengths of solid rods, etc. Some say they "morph" with observation, and others say they don't, but that we can't know their descriptions/measurements for sure, because of the "cast in stone" dictum, "There are no preferred frames of reference." Yet what scientist would not prefer being at rest with an object or length being examined and measured over flying by it at near lightspeed? It is a false dictum, even if it is mainstream SR theory. The results are clear and obvious if one is open to the evidence, which is well established with a long history of studying Earth. It is not in fact a severely oblate spheroid with a 1000 mile diameter, as per the high speed frame of reference we have beaten into the ground here. It is very nearly spherical, and we *know* its dimensions precisely from this long history of at-rest observation. There have been *no observations* of earth from the overworked high speed frame of reference. And if it were seen as above, that would only require the Lorentz math to "transform" it to its true shape. I think its time to "get over" a squished nearly flat earth, an AU of 1/8th or so of the well known average distance of 93 million miles or so (8+ light minutes), and a meter rod of 12 cm or so, all based on this false dictum.

I did a thorough review, below, and yes I have questions. From abstract to specific is always "better" for realism, but it was not essential to your graphs. Graph, post 276 shows observer stationary, and from his perspective light pulse travels 10 units of distance in 10 units of time; flashlight travels 2 units of distance in 10 units of time. Post 279, first graph, from flashlight’s perspective: In 8 units of time, observer appears to have moved 2 units of distance closer to flashlight while light pulse traveled 8 units of distance, intersecting (and being seen by) observer. Second graph, from observer’s perspective: Light pulse has traveled 10 units of distance in 10 units of time, while flashlight has traveled 2 units of distance in 10 units of time. (Same as graph in post 276.) You note that that is “slightly odd” and show that in the same time span, flashlight has traveled .5 distance units (looks like lots more on the graph) while light pulse has traveled 4 units, a difference of 3.5 units. In graph three I see the observer moving 4 distance units toward the flashlight in 10 time units while the light pulse moved 6 units of distance in 6 units of time, intersecting the observer. In the last graph: The light pulse moves 10 distance units in 10 time units, intersecting the observer, while the flashlight moves 6 distance units toward the observer in 10 units of time. This means that the flashlight traveled .6 times lightspeed. Then you have another bracketed distance of 1.5 units from 2.5 to 4 on the distance scale, indicating the difference between flashlight’s and light pulse’s distance traveled in the same time span. You note: Tell me please, if i understood all that correctly, and then, please, if you will, tell me how those differences indicate length contraction, in the “real world,”... This is a thread in part about the idealism, as I see it, of *theoretical* length contraction vs the realism that actual distances (or shapes or rod lengths, etc.,) do not change with measurements of them. That was the point of my scenario with a one AU 'track' of sorts laid out for two observes with lasers coming at each other. Ps: Do you agree with Iggy's final statement in post 280?: My "in the real world" scenario addresses the 'whole one AU 'track' and the over-all reality of who sees what and when and where along the track, not isolating "for the observers" (one take), and "for the light beams" (another take.) It is looking at the situation as a whole, i.e., the philosophy of reality not limited to individual frames of reference.

And, to back up a bit... Me: Swansont I have repeatedly argued that the closer we are to at rest with objects measured the more trustworthy the measurements. I have also repeatedly emphasized the importance of record keeping for science. There is massive and undeniable evidence from centuries of measuring earth from the at rest frame to verify its very well known measurements and description and no measurements done from that near light speed frame relative to earth which might give it a (clearly wrong!) 1000 mile diameter. Your argument above is in serious denial of the facts. And you clearly subscribe to idealism in your denial of realism as per my statement: "actual objects and distances are not dependent on how they are measured..." The distance traveled by the flashlight is clearly less than the distance traveled by the light beam. We all know that a flashlight can not go as fast as the light it emits, nor can it make the light go faster via cumulative speed. I find the graphs more confusing than examples laid out in "real space", i.e., using a well known and established distance for the illustration, as I did, but still employing the same "players", i.e., light, moving light emitting source(s), and observer(s).

Yes, it is strange that light can not be pushed faster by a speeding flashlight, or laser, as in my scenario above. But it still makes since to me because light is not substantial like a bullet which does go faster from a gun speeding in the direction of the shot than from a resting gun. But my beef with SR is the claim of length contraction, and I don't think you made a case for that above. That is why I asked you to take your flashlight and observer out of graph mode and put them in the real where we do actually know distances between objects like earth and sun. So I did it anyway with two ships one AU apart. Please review that scenario and reply to the point that there was no length contraction when seen as a whole, not limited to the frames of reference involved. The light of each ship would have traveled the whole distance between the starting points in 8 minutes, so I backed it up to find out when they would see each other's light if they were traveling toward each other at half lightspeed. In 6 minutes they each would have traveled 3/8ths the distance while their lights each travel 3/4 the distance, having just past the opposing ship, each now 1/8th AU beyond their own 1/4th AU position.. So the point of seeing each other's lights is 5+ minutes out and between their respective 1/4 Au and 3/8ths Au marks. Again, no lengths contracted. Swansont: We can as long as we "transform" them to accurate descriptions of the real world. If some aliens are on a near lightspeed mission to measure and describe or solar system and report back and they measure very oblate spheroids for all bodies in our system, their bosses back home would think ours a very strange system or they forgot to do the transformative math.

Yes. The observer sees the light go about 10 units of distance in about 10 units of time while he sees the flashlight travel only about 2 units of distance in that time. Sorry but this has not yet made the case for length contraction in my mind. Maybe you are still working up to it, but I'm gone 'til Monday. I give up yet again on communicating with you. The ships are moving toward each other from opposites ends of a one AU long "jousting arena." I said it clearly already! They fired lasers (at lightspeed, obviously) toward each other as soon as they took off at half lightspeed. They see each other's beam just before 6 minutes of travel, during which each ship traveled 3/8ths of the distance while their lights traveled 3/4ths of the distance. The point, yet again: No distances "contracted."

Yes, it's crystal clear. The observer sees the light after about 8 units of time have passed and he has traveled a little over 8 units of distance. I agree that: "It doesn't matter how it's measured: light will move at c,..." But your point about length contraction would be more clear to me if you abandoned the graph and laid it out, as I suggested, "in the real world", say between sun and earth for reference points. That was my intent with the laser-jousters scenario above, and the point was that neither the whole AU distance nor any part of it contracted during the journeyers' six minutes of approaching each other at half lightspeed while firing lasers at each other. To my exchange with swansont; Me: Swansont; The cosmos is not real without our measurements? That is a form of idealism, with "frame of reference" substituted for "subjective" in "subjective idealism." This philosophy goes all the way back to the absurd (cliche') claim of idealism that a tree falling in the forest doesn't make a sound if it is not heard. Iow, the world has no reality of its own but rather reality is totally dependent on perception and measurement. I have repeatedly argued that we can trust measurements at rest with what is measured "hands down" over all those theoretical, extreme, near-light-speed frames of reference upon which the unverified theory of macro length contraction depends. The former gives the 'earth science' description of earth, while the latter gives us an earth of a 1000 mile or so diameter, which is, by all accounts (save the above extreme) wrong. Moth: Hey! Like Cap 'n R said about his, this is my thought experiment. You are making it way too complicated. Please reconsider my closing "point." To Iggy's question; Me: Iggy: Yes, in this phase, before the "rewind." They both began firing lasers and took off toward each other at the same time. Their lasers would have gone the whole 8 light minute AU distance (past each other) while the travelers, at half lightspeed went half the distance. I just started simple before backing up to the shorter segments (fractions of the AU) to see when they would have seen each others' lights. Note: I'm gone for the weekend again.

All of this of course requires a high tolerance for ‘cognitive dissonance’, as we call it in psychology. As a realist, this seems like a mind game full of trick questions. The base line reality check lies in the answer to the question: “Can light have a constant velocity *AND* can solid objects’ shapes/lengths and distances between cosmic bodies remain un-affected by measurement, both true at once?” This is the philosophical question. Now back to your brain teaser/ trick question. (In gaming mode here.) The observer, any observer, will measure the speed of light he sees to be 186,000 mps regardless of how fast its source is going. That is SR. But I think that ”how the observer would see its velocity compared to the flashlight” would depend on whether he had a fix on the whole beam from those far end photons at the front of the beam to those continually being emited from the flashlight. It is very complex, and no arbitrary frame of reference has a perspective on the whole situation, transcending the local points of view. So, I will have to go with not accepting the limitations of the frames of reference employed in the thought experiment. As a realist, I try to stay out of that “box*” anyway. (* Everything depends on frame of reference.") I did run the numbers on my little game mentioned in last post. Here is what i came up with: A and B are one AU apart (lets call it a nice round 8 light minutes.) They each flick on a laser aimed at the other as they miraculously take off toward each other, each traveling at one half lightspeed. The game question is, how long before they see each other’s light and where are they along the one AU length? Ans: Progressively, A and B would both reach the half way point (X) and run into each other in 8 min at half lightspeed, and their lights would each have gone the whole AU distance. So to answer the question, a little “rewind” reveals that each traveler would have traveled for 4 minutes to reach the quarter AU mark (from their respective starting points) while each of their laser lights traveled to the half way point and met in the same time. (Not there yet to see the other’s light.) Six minutes of light travel from either laser will reach the 3/4 AU mark away from each starting point. (No push from either traveler's velocity.). The same six minutes brings each traveler to a point 3/8ths AU from their starting points, an 1/8th past other's 3/4 out mark, having just past the point of seeing ther other's light. I'll leave the precise math to hair splitters who love the math. A long way around to this point: Neither the AU nor any part of it “contracted” during the operation. And the creator of the scenario gets to see the whole thing from transcendental perspective, not limited to either A or B’s frame of reference.

Me: Swansont: Thanks a lot, considering you know that I am not a mathematician. But the meaning of the concepts involved does not require math, as I've pointed out (and quoted from the Ross paper) many times. Coordinates are the map, right, not the territory. Transformations convert the light speed measurements requiring mathematically ‘shorter distances’ (as required by the scenario above) into actual distance traveled through the ‘territory’ like between earth and sun above, right? The alternative is that solid rods, earth’s diameter and earth-sun distance is like silly putty at the whim of those coordindinate systems, Right? If the cosmos is real, with or without our measurements (or humans, for that matter... see my thought experiment awhile back), then actual objects and distances are not dependent on how they are measured, Right? I was using the 279,000 mps as an illustration that lightspeed is not cumulative as beamed from a moving source or as seen from an approaching source... not attributed to you. I really don’t know how the “great mystery” of constant ‘C’ works except to reiterate that light can not be pushed faster than ‘C.’ So, lets let the flashlight be moving at half lightspeed (for simplicity sake) and shining ahead in the direction of travel. As above, that does not boost the beam to 279,000 mps, so the flashlight must be moving through the tail end of the beam at half lightspeed even as the front of the beam continues at 186,000 mps relative to a distant target (at which the light is aimed.) Does this make sense? Now I’ve got to go back and study the details of the Michelson/ Morely experiment and later verifications. (Just completed a brief review. Created more questions about equipment and experimental design than answers, of course. More homework... ah, the adventure of science!) What do you think of my reply to swansont above? Ps: Oopse, just caught a glitch. You said: I agreed that the distance between the photons at the front of the light beam and the flashlight increases at lightspeed, 186,000 mps. The observer was approaching at half 'c', seeing the flashlight getting 93,000 miles closer every second. Why don't we maximize complexity and have two light sources speeding toward each other at half 'c' (combined velocity, 'c') while shining their lights at each other. Who sees what when then?... or not!

If space is the vacuum (no-thing-ness) in which things and forces exist, there is no need to make some-thing out of no-thing. My point is that things and forces exist in and travel through space ( permitivity, permeability) without making space into an expandable medium. Is emptiness/void a "property" or a lack of properties? Properties are usually assigned to things and forces. Einstein said that if all energy and matter disappeared from the cosmos, that space and time would also disappear. I can see that being true for time, because of my definition: event duration for physical processes. No physical processes, no time. But, with nothing left in the cosmos, it would leave empty space, no-thing-ness. Just an ontological distinction. On small scale, take all objects out of a box and you have an empty box, empty space (ignoring air for this point.) The first paragraph does make sense. From the perspective of the observer, the flashlight beam has traveled toward him at 186,000 miles in a second and he has traveled toward the flashlight (or the latter toward him, same thing) 93,000 miles in the same second. So the flashlight did not "push" the light beam to give it a cumulative speed of 279,000 miles per second, as if it were a bullet shot from a gun. No matter how fast the flashlight travels (under 'C'), or the observer approaches the flashlight, its beam can only go light's speed limit. Now, put this scenario in "the real world." It is 93 million miles from sun to earth. That will not change while the above observer approaches your flashlight and its beam. Say you and your flashlight are in space close to earth and the observer is a few light seconds further out between earth and sun approaching you at half 'C.' It the second discussed above, he gets 93,000 miles closer to you, and your light beam gets 186,000 miles closer to him. Meanwhile, no segment of the distance between earth an sun has shortened. The Mystery of Constant Lightspeed (granted) does not make distances between objects in the real cosmos shorter... or solid meter rods, or earth's diameter.

First, I agree that 'C' is constant regardless of frame of reference from which it is observed, so maybe your argument is unnecessary. Anyway, backing up a bit: Cap 'n R: Not sure what "increases." "It" meaning "light's position?" Your beam still approaches him at 'C' even though he is approaching you at half 'C.' Is this what you mean? You continued: So, the apparent paradox is that, even though he measures light at 'C' velocity relative to your flashlight, it is also approaching him at 'C' velocity, even though he is approaching you at half 'C' velocity. I still don't see how all of the above illustrates anything more than that 'C' is constant from all frames, to which I agreed up front. Then the question is, "How does that fact make solid objects like metal meter rods and earth's diameter shorter?"

I'll go a piece at a time. Yes. Light doesn't "care" from which frame of reference it is observed. It goes from here to there at the constant rate we all know, no matter from where it is observed... (and that makes no intuitive sense, even though it is true from empirical observation.)) So "the photons" above are the front of the beam of light. So far OK?... and they are going at 186,000 mps away from the flashlight. I think so. Not sure, because I don't know what you mean by " the light's position." The moving bodies ("someone and me") will see both see a light before they see the emitter of the light in each case. Damn! another interruption which I can not ignore.

Yes. I also see that light can not be pushed faster than 'C' by a high speed light source, if this is relevant to your point. And it doesn't go slower than 'C' relative to an observer if the source is speeding away. Constant 'C' does not make solid objects or astronomical distances in the "real cosmos" shorter.

Swansont: I am specifically critical of certain aspects of relativity, like spacetime curvature in GR and objects morphing out of shape, depending on how they are observed, as per the empirically unverified length contraction theory of SR. You can flunk the whole Society for the Advanced Study of Spacetime for criticizing spacetime, if it makes you feel superior, but that doesn't make them (or me) wrong. You state as a fact that length is not invariant based on the unverified hypothesis (for objects like earth and rods and distances like the AU) of length contraction. This is not science. It is conjecture based on an untested hypothesis. You seem totally blind to this fallacy. Taking earth's diameter as a contracted length, you must contend that an earth with a 1000 mile diameter is equally as accurate as an earth with an 8000 mile diameter. This is total nonsense. Substitute "earth's diameter" for "length" in the above. (It is equivalent in meaning.) Can you now identify the absurdity of your "logic?" Yes, earth's diameter is independent of observation and measurement. I know how to hit the framed "reply" button to get a stamped quote. I choose not to do so quite often for the result above. I can interject comments specific to each quoted point rather than having the whole post in one block to sort out. I am not concerned about the convenience of your automatic notification.

Iggy: Please get a grip. You even quoted me as follows: Shape, which is intrinsic to objects according to realism, and velocity, which is always relative to some reference point, as I have often belabored, are not logically interchangeable. I have said that earth has one velocity relative to the sun and another relative to galactic center. I also went into detail about the velocity of a car relative to the road and another relative to the center of earth, etc. It is very difficult to communicate with someone with such a short memory, let alone such a weak grasp of logic. You say: ... as if the rigid shape of a body (not changing with observational perspective) were logically interchangeable with velocity or change in velocity (acceleration), which, as above is relative to point of reference. (another repeat for clarity.) There has been no refutation of realism. Earth is not both very oblate and nearly spherical It is one or the other, and the unverified theory of large scale length contraction is not even close to a possible contender for an accurate description of earth's shape. It does not, in fact, have a diameter of 1000 miles, no matter how you look at it.

The topic of this thread seems to have run its course without resolution. I will make another attempt at the latter by reviewing selective quotes from the argument between myself and Swansont from page 12. Bold will signify unanswered questions or challenges. From post 221: Swansont: Realism asserts that objects in the real world have intrinsic shapes independent of how they are observed. So the question, "What shape is earth?" is nothing like the assumption that one is beating his wife, leading to the question, "Have you stopped?" Me: From post 230: Me; Swansont: So, the universe does not exist as a reality independent of observational frames of reference? Pure idealism. Swansont on evidence for large scale length contraction: As argued more than once already: Muons incoming through the atmosphere “live longer” than muons in a particle accelerator, so they travel further than expected. The atmosphere does not get way thinner around the former, as length contraction would have it. Swansont: Me: Swansont: Me, from 233: Swansont: Me: Swansont: You never replied to my challenge to show how my logic was flawed. Swansont: Me: Swansont: Again my argument is that there is no evidence for length contraction beyond subatomic scale. I am not an atomic physicist, so I do not know how they got length contraction from measuring the distance between the “end points” of subatomic particles (yes, they are real) in an accelerator. No red herring. If earth stays the same shape (as all but you agree,... no “morphing”, as Cap ‘n R agreed), it can not be both nearly spherical and very oblate. It must be one or the other. If it were to be measured as having a diameter of 1000 miles through either the equator or the poles... (length contracted to 1/8th as per Cap 'n R's scenario) rather than the well known and validated 8000 or so miles, the former measurement would be in error. Even after so much repetition, as above, the basic challenge has not been addressed. This post will be my last attempt at resolution if the realism vs idealism issue is still not answered.

Md65536: A personal attack immediately takes points off in a logic debate. My one semester class was full and cited for merit by the dean of the Philosophy Dept. Your insult sets the sophomoric, personal attack tone of your argument. As for the above snide insinuation, at age 66 I am retired from my private practice in psychology, and my brief tenure as a teacher of that class was a one time thing... a one semester special studies elective course with focus on the place of logic in science. (I taught other "special studies" courses in psychology.) I found your analysis pedantic, tedious even, and having missed the point of my premise: Either the world/cosmos exists in and of itself, as it is, with intrinsic properties independent of observation, or it's existence (and properties) are dependent on how they are observed. The former is realism and the latter is idealism. Maybe that is too simple for you to understand. Not my problem. More personally insulting insinuation... that I am closed minded. My colleagues know me better than that. "Immovable resolve" is quite a judgmental characterization of me. I have been an amateur scientist all my life (since I could think for myself) and I say it as I see it, with the benefit of a hereditary high genius intelligence, as measured by both the SBIS and the WAIS, in case you missed that post.

Swansont: You may be a brilliant physicist, but you would have flunked my class on Logic and the Scientific Method. If you see a flaw in the logic I presented in my last post, by all means specify the flaw. There is no "false dichotomy" in the "either/or" ( or "if/then") conditional (not a syllogism) logic I argued. Either objects exist and have properties independent of observation and measurement Or they don't. If the latter, then then their existence and properties depend on how they are observed and measured. Obviously there are "things" beyond science's ability to observe and measure them. (Or would you also disagree with this?) This means that the cosmos with all its properties exists and has intrinsic properties whether we observe and measure them or not. (Repetitive, but it seems necessary.) Do you agree with this or not? If not, then you are an idealist. Moth: No problem with the "off topic" issue. The ontology of space, time, spacetime, and what is real, independent of observation, measurement and conceptual models is all interconnected. Ontology investigates what exists and the nature/properties thereof. If space is some kind of expandable/contractable medium, then the "burden of proof" is on those who make that claim to show empirical evidence for it... which can not be explained by observation of moving objects without such "entities" as "expanding space", "curved spacetime", "dilating time" (not just clocks slowing down), etc. The force which is making the objects in the cosmos move away from each other at an accelerating rate is still a mystery to everyone. I thought it might be masses beyond our cosmic event horizon pulling the visible cosmos outward, but the "shell theorem" of gravity presented by Spyman in another of my threads seemed to invalidate that cosmology. (But multiple "Bangs" at different epicenters beyond our visible cosmos would make the shell theorem irrelevant....Way beyond the topic here.) Please explain what you mean by "mutable even if not tangible" here: "If expanding space IS causing the universe to change this way then space can be mutable even if not tangible." Ontologically, if 'something' (space) is said to be expanding, then it must be some kind of entity besides empty volume, which is a lack of entities or the vacuum between entities. Same for "time." Clocks obviously "tick" more slowly at high velocity and higher gravitational fields, which complicates the math for GPS clock synchronicity vis-a-vis surface travel positioning. But "time dialtion" grants "time" the ontological equivalent of status as an entity. So that requires that everything in every different velocity or gravitational situation has a specific time 'environment' around it as it moves... which is clearly (to me) absurd. (What is time but event duration for physical processes?)

Swansont: Me: Swansont: My philosophical argument in this thread is that the world/cosmos is real and has intrinsic properties independent of observation and measurement. The idealist argument is that nothing is real but our observations, including scientific measurement. You say, "what we measure is reality," which makes you an idealist. To verify that I asked, " does reality require our measurements?" You say that things we can't measure are "arguably real." What, 'maybe so; maybe not'? This is a hedge. Does reality require that it is measured or not? If not, then you grant that earth has a shape independent of how it is observed/measured. You can not have it both ways, logically speaking. If objects have intrinsic shape which does not drastically change with frames of reference from which they are observed (my argument), then all science has to do is eliminate variables of observation which introduce error or unknowns like, "is length contraction real in the objective, observable world of planets and rockets?"... which is not verified. As I've illustrated with examples (like the microbe under a microscope vs flying through the lab at near 'C'), I argue that at rest (not moving) relative to what is observed/measured will always yield the most accurate measurement or description. Moth: Off topic, but for the ontology of "what is space?" If space is empty volume but for the things which occupy space, then more space between objects is always due to their moving away from each other, not "space" (empty volume) expanding. I do not dispute that galaxies are moving away from each other, or that their rate of doing so is increasing. An expanding cosmos (with increasing rate of expansion) refers to the stuff in space, not 'space itself' if "it" is just the volume in which the stuff exists.

Me: Moth: There is a large body of papers from a decade or so of conferences convened by the International Society for the Advanced Study of Spacetime. (See my spacetime ontology thread in "Philosophy.") This society takes nothing for granted about space or time or spacetime. The nature of ontology is to take nothing for granted, even the sacrosanct combo of space and time as a very malleable "fabric" without a referent in the observable world. Moth: It is not only possible but frequent that theorists come up with very complex models that have no *referents* in the observable world of objects and forces. Many think 'spacetime' is one of them, a "map" in the mathematical/physics mind of scientists but signifying nothing in the world of matter and energy/forces. Gravity does not require "spacetime" to work. But it is a sophisticated model, kind of a scaffolding for the math. My take, anyway. Moth: Please elaborate with examples of objects with "recessional velocities increasing with distance." Velocities depend on the forces which propel the objects (and gravitational forces which pull on them), not on distance traveled per se, unless away from a gravitational force, which will allow more velocity from internal propulsion.

Swansont: What about what we don't measure. Is that reality too, or does reality require our measurements? Cap 'n R: Earth will probably not appear spherical if ever visitors at extremely high speed observe it on the near 'c' fly by. But they will probably be intelligent enough scientists to mathematically "transform" the very oblate spheroid they see (visibly contracted as it might appear) into the nearly spherical planet that has a shape of its own, not dependent on how it is observed. And the fact that no one has ever done it before leaves the version of the very oblate earth in the realm of unverified theory (not to mention physically impossible, in a universe of real, nearly spherical planets),... while all the science done on earth makes it out to be nearly spherical. How long will you continue this farce? (a rhetorical question, of course... in a humorous spirit... no answer required.)

Please read my comments in the ontology of time thread (in "speculations" at the whim of moderators) and get back to me. I have defined time as event duration of physical processes. Not an entity. Nothing to expand (the meaning of dilation.) Do you agree? To me, space is obviously just 3-D volume on all scales, from between subatomic particles to between galaxies to all the space there is... infinite, in that there is no "end of space." (What boundary?... what beyond that?) Not an expanding mystery medium, even if that is "mainstream science." The space between objects "expands" as things move further apart, not because "space itself is expanding." Just another point from ontology of space... not of interest to physicists who "believe in" the mainstream doctrine of expanding space.

md65536: Hmmm... would you please rephrase the question? Anyway... It would be a case of "Have you stopped beating your wife?" if I attempted to explain my "false dichotomy." I would "fit someone" of that description (depending on the specific "aspect" of reality they believe is intrinsic or objective ) into a selective sub-category of idealists who grant reality "independent of our conceptual schemes" to all natural phenomena except, for whatever reason, length/diameter of certain objects and distances between objects in the natural, un-measured cosmos.