owl

None that I know of. How cryptic. You must have a point. Maybe that the near light speed frame is only hypothetical and has no empirical evidence to support it. No... that would support my argument. Please explain.

Me: Swansont: You constantly criticize me for lack of supporting evidence. I say that there is a mountain of it for a nearly spherical earth and none for a very oblate earth... a hypothesis with no evidence to support it. I repeat that seeing it as different shapes from different points of view (frames of reference) does not make it different, and that would be an idealist's assertion. Since all agree (I thought) that it doesn't "morph" (change shapes),it is a specific, unchanging shape. Is it nearly spherical, as per at rest frame, or is it extremely oblate... in the real world? Pick one, unless its all about how you look at it (idealism) and it has no objective, intrinsic shape. Which version has actual evidence to support it? "No, we don't agree that the earth doesn't drastically change shape." Fight it out with Cap 'n R. Does it "morph" (drastically change shape) or doesn't it? (Ans: No, it doesn't.) You continue to miss the whole point of this thread, which compares idealism to realism. Realism realizes that the universe has a reality independent of observational frames of reference. Science observes from as error-free point of view as possible, makes records and so determines things like the shape or earth... which is not in dispute, accept among eccentrics with an un-verified theory about length contraction. Seeing things as shaped differently from different points of view does not mean that they actually are shaped differently, depending on how you see them. How many times must I repeat this before you get it. If you disagree, you are an idealist. If you are an idealist, admit it, and I have made the point of this thread's philosophical argument. "In forming the argument you have presupposed that length is invariant, and it is not." In saying that it is not, you have presupposed that reality is dependent on how it is observed, which is the argument for idealism. Realism does indeed suppose that things are as they are intrinsically, in the real world, independent of how they are observed. Me: Cap 'n R: Trivial? Could that be a judgmental bias from a physicist without a clue about, or interest in the ontology of spacetime? I think so, since you have never replied to my persistent ontological challenges to what spacetime is. Some scientists think that it is appropriate to investigate what something (spacetime in this case) is as required information relevant to how "it" behaves. You seem to have missed this piece, probably because it is in the despised field of ontology, mere philosophy. Some (Brown, Pooley, and many others) say that "it" does not exist. ... That it is a concept without a referent in the world of interaction between masses... that "it" is unnecessary to gravitational attraction between masses, and theoretically "parasitic" upon the empirically observable physics of gravity. Einstein said that space and time would not exist without matter/energy, so where does that leave them (and their combined "fabric", spacetime) as entities, a medium, whatever besides just a concept?

'Cap'n Refsmmat' timestamp='1314647963' post='624199' You clearly find this hard to believe, but I have studied "spacetime" for several years and find myself in agreement with its critics! I suggest, yet again, that you study the two volumes edited by Deiks, Ontology of Spacetime, which investigates what it is that the theory refers to when it applies the noun, "spacetime," rather than just taking its existence for granted, as you continue to do. As you know, this is also the focus of my thread on spacetime ontology. Likewise with the ontology of time specifically. 3-D space is obvious. The only thing obvious about time is that "it" elapses as things move. So when you say, "distance through time and distance through space can intermingle," it is not like they are both entities of some kind to be taken for granted and not questioned. Rather, moving through space (distance, as the linear component) requires time, i.e., the duration of the movement in question. This avoids reifying time and space as entities and empirically describes objects and their movements through empty volume without 'weaving them together' into the very debatable entity, "spacetime." Me: Swansont: You didn't reply to any of my supportive evidence for a spherical earth and the lack of evidence for an oblate earth. As for the logic, I have been over the following argument several times. We agree that earth does not drastically change shape. In other words, it stays the same shape, regardless of how it is viewed. So, what is that shape? Is it spherical or is it oblate? It can not be both. If you say that it depends on how you look at it, you are an idealist, and I rest my case. Were you able to follow that logic?

Iggy: I have said that even with no observer, the speed of light is constant. No convoluted mind games needed. A photon from a light source travels at 186,000 mps (regardless of conventional units of time and distance) away from the source and toward its destination. The big mystery is that, to keep it simple, radio waves, traveling at lightspeed, do not gain speed when the source is moving toward the radio receiver. IOW, I agree that light can not be pushed faster by a source with velocity toward an observer. (It is not like a bullet from a moving gun.) It lacks mass, so there is nothing substantial for the source to push against. this does not mean, as constantly argued by length contraction advocates, that, "therefore the distance must get shorter." I have said that "now" is the present. No boundaries or signal delay restrictions needed. No denial that it takes time for light to travel any/all distances. I have said that the distance between objects is intrinsic, not dependent on measurement, and it varies only with the movement of objects relative to each other. The "remedy" is to quit superimposing the dogma that 'everything depends on frame of reference and measurement there-from' on the cosmos. Four dimensional space or 3-D space plus time? If the latter, how does elapsed time have anything to do with shape? If the former, please describe the fourth spatial axis after length, area and volume.

All this derision of my logic and yet no one has even addressed the fundamentals of objective realism vs idealism. So, I will back up to my closure in post 201 and say again: And still no one has answered this direct question (emphasis added): Not, “How does earth look from different points of view?” but, assuming earth has an intrinsic shape independent of how it is viewed (as per objective realism), what shape is it? It is nonsense to claim that if it is viewed one way it is one shape, and if viewed another way it is another shape. It is not two different shapes, depending on two different frames of reference. Call me nasty names if it makes you feel superior, but the above is still nonsense. No one replied to the argument that record keeping is essential to science either, and there there are, of course, abundant records verifying earth’s nearly spherical shape and none verifying a very oblate shape. The basis of my thought experiment was the argument from objective realism: that earth/cosmos and the relationships between all objects have an reality independent of how they are observed. Length contraction denies this and asserts that how things are observed determines their properties, which is idealism in denial of objective realism. My logic says that if you grant objective realism then frame of reference does not determine reality. If not then "length contraction" depends on idealism, and reality is determined by how it is observed. The task of science is to investigate that independent reality with as few errors as possible, and my argument is that extreme frames of reference are more subject to error than the at rest frame with whatever is investigated. I have given many examples. One would think that length contraction advocates would get a clue to the above when comparing all the records of earth’s spherical shape to the hypothetical very oblate spheroid shape. It is nonsense to say that the latter is equally as valid as the former. It requires a dogmatic belief that "there are no preferred frames of reference" when all the evidence points to the accuracy of the at rest frame. There is no evidence for a very oblate earth. It requires a “head in the sand” attitude to believe that a nearly squished flat earth is a scientifically valid description. Plus it makes scientists look like "flat earth-ers" without a grip on reality.

I’m gone for a long weekend after checking in tomorrow morning, so I want to ask an important question before go, just to simplify the issue presented in this thread, and I will post this before reading anymore replies from this afternoon. (Tired of the level of quibbling here with dogmatic believers in length contraction.) Many physicists in this forum may not think logic is very important to science, as it is a branch of philosophy, and philosophers are not (often) serious scientists, many think. But as mentioned before, I have taught undergraduate “Logic and the Scientific Method" at the university level. With that in mind, let me ask the forum a sincere question: Is earth a very nearly spherical body or is it a severely oblate spheroid, say with diameter through the equator 1/8 th the diameter through the poles, or vice-versa, depending on frame of reference?

I would like to ask others in this forum whether you believe that an earth with a 1000 mile diameter, as measured from the extreme frame of reference we have worked to death here, is an equally valid scientific description of earth as the well known 8,000 mile or so diameter. Whoever believes that the former is equally as valid as the latter is an idealist who believes that frame of reference determines reality, just like subjective perception but with an abstract point of view as 'subject.' Of course, "all hell would break loose" if earth were actually 8,000 miles pole to pole and 1000 miles through points on the equator... or vice-versa, depending on which direction the near 'C' travelers were heading, with the axis or 90 degrees to it. Since there has been no empirical observation of earth from the above extreme frame of reference, I have no idea why swansont keeps appealing to such as a verification of the above extreme example of earth's shape. If DrRocket is correct, and I believe he is, there has been no verification for length contraction outside a particle accelerator, specific to the above example or the often debated shortened version of the meter rod. I will just briefly summarize my argument against the assertion that the atmosphere is way thinner than the standard 200 or so miles "for incoming muons." No one has yet even addressed my argument which intends to debunk that nonsense. Yes, they live longer and travel further than expected compared to lab muons. Again, there is NO empirical data for an earth of 1,000 miles diameter or a meter rod of 12 cm, but there is abundant evidence for the nearly spherical earth. Further, there is no physical explanation, let alone evidence for the contracted diameter of earth or shortened meter rod. Finally, has anyone here considered a cosmos independent of measurement, (as per my post above) i.e., with intrinsic properties of its own which do not vary with frames of reference from which they are measured? That is the objective realism cosmos. Then the question is how best to accurately observe objects. I have been over this many times. It is nonsense to believe that flying by earth at near lightspeed is equally as accurate as at rest. And how about that microbe. Shall we observe it under a microscope or get a snapshot of it as it flies through the lab at near 'C?' Equally valid result? No. Also, record keeping is essential to science, and a mountain of records say earth is nearly spherical, while none say it is a very oblate spheroid. The frame-of-reference dependent cosmos with all points of view being equal is based on idealism. It makes the world/cosmos "subservient to" (as in dependent on) how it is observed. And it requires some common sense to decide from which frame of reference to study a given object for best accuracy. Does anyone get this? Certainly not swansont. This is the philosophical issue that this thread continues to address.

Schrodinger’s hat: In the thought experiment I asked you to consider (which you continue to refuse), there is no “according to the people,” because there are no people. Light from the sun or any star, or any source travels from the source at “lightspeed,” which, of course, is constant. Your, "according to the people" insists on a frame of reference, while I argue that frame of reference does not determine reality in objective realism but only in idealism. This does not deny that the light source is obviously the reference point from which it travels, 186,000 miles further for every second it travels. (More editing for clarification) Also, obviously, light traveling toward earth gets 186,000 miles closer every second... which I thought goes without saying, but...) Science based on objective realism will not grant equal validity to a severely oblate earth (of say a 1000 mile diameter) or an AU of only 12 million miles. So, the question, "How oblate is it, objectively, and why?" is really beside the point if you endorse the validity of an earth of 1000 mile diameter as seen from the extreme frame cited in support of length contraction. Swansont, First, this an off-topic attempt (initiated by Iggy) to derail the philosophical point of my post of 8/24. Second, I was using "centrifugal force" as the concept is commonly understood, notwithstanding the technical disclaimer that it is a "fictitious force." I will repeat the common understanding from Wiki: As a kid hangs on to the rotating device, centripetal force, toward the center of rotation, holds him on. When he lets go, centrifugal force as commonly understood above, away from center of rotation, throws him off. Yes, his inertia will carry him tangent to the spinning disk. ... And, yes, technically speaking, one could re-define centrifugal force as lack of centripetal force Wiki continues: Do you suppose all those devices should be renamed for the “real" dynamics involved with all of them? What would you like to rename a centrifuge? How a bout “lack-of-centripetaluge?” Can we get back to my topic now?

swansont: Assertion: That earth is nearly spherical, based on all the scientific evidence and compiled data since earth was thought to be flat. S: Double-talk. Have you ever been thrown off a playground "merry-go-round" that got going too fast? (I don't know; maybe you never played. Just a whimsical aside.) How real was that force, which throws one off? Very real when you hit the dirt... or foam padding, as the case may be.

Swansont, So, no specifics against my argument, as usual. Just, ‘you are wrong, cuz relativity, in all its particulars (including length contraction) is right.' No addressing: This is the cosmos according to objective realism. No flattened earth. No shrinking or expanding objects time or distance* as different observers see things differently... or: Distances between objects vary only as they physically *move* closer together or further apart. (Nobody is flying around at near lightspeed taking measurements!) Iggy: You are really not paying attention, as usual. Sunlight traveling from sun to earth has the well known constant velocity relative to both sun and earth. From Alpha Centauri to earth, its velocity is relative, again, to both source and destination of the light. (186,000 mps from sun or Alpha Centauri to earth.) Ever heard of centrifugal force? Wiki: The spinning of earth for ages has pushed out a bulge at the equator where inertial centrifugal force is at its greatest.

You still didn't get the point of my post, re-iterated above: "Setting aside relativity" for the moment..." Specifically, just for now, if you are willing to indulge my thought experiment (apparently not)... Consider a world/cosmos "as it is," independent of measurement... Sunlight always takes a bit over 8 minutes* to reach earth (*regardless of specific conventional time units), and there is no traveler going at near lightspeed trying to measure distance or travel time... in my presentation. They tell me* that "for a photon" there is no distance between sun and earth and no travel time. But "reality for a photon" is significantly different than the Reality of sun and earth and their relationship in space and light's actual travel time. *(Others say a photon has no inertial frame of reference. I suppose that is why you knocked 6000 mps off lightspeed for the traveler's speed.)

"Setting aside relativity" for the moment... Its speed from sun to earth, as above, is the same as its speed from Alpha Centauri to earth... constant, like 186,000 mps without the "miles" or "seconds'... or, light from galactic center to earth... same speed.

Follow me if you will on a journey into objective realism. This will require setting aside for the moment the dictum/dogma of relativity that everything is relative and that there is no preferred frame of reference, i.e., that measurements/descriptions of objects from all frames are equally correct. So, imagine a world/cosmos with no intelligent observers and no clocks or measuring sticks. It does not disappear just because it is not being observed and measured. It is intrinsically real and has intrinsic properties. Galaxies form and diversify into solar systems and planets. Most of the latter (stars and planets,) due to the well known laws of physics, are nearly spherical in shape, though no one is around to observe that fact. Distances between objects vary only as they physically *move* closer together or further apart. (Nobody is flying around at near lightspeed taking measurements!) *Movement* takes “time” (duration from here to there) even though nobody is “clocking” any particular movement event. All objects and the space they exist in are three dimensional, not counting the elapsed time factor,( not another “dimension”) for movement. There is no one around to invent a fourth dimension, but three cover all the axes: line, plane, volume or distance, area volume. Space is simply this volume, on all scales, whether the space between subatomic particles, stars and planets, or galaxies. Light travels at a constant velocity through space, so it still takes exactly the same amount of time for sunlight to reach earth even without assigning time and distance units to this velocity. This is the cosmos according to objective realism. No flattened earth. No shrinking or expanding objects time or distance* as different observers see things differently. (*Except as natural growth/shrinkage or, as above, objects moving closer or further from each other,) At this point I feel like resting my case as argued in this thread. I could be talked out of it, but that would require that respondents were actually able to fulfill the above opening requirement, not just continue beating the drum for “everything is relative to observational frames of reference.” Thanks to whomever actually “followed me” on this one.

Schrodinger’s hat: “Space and time are the same quantity.” me: “Saying so doesn't make it so.” My point is to be taken at face value. You state the above as a fact. I disagree, but my saying ‘space is 3-D volume and time is duration of movement through space’ doesn’t make it so either, though I believe it is true, based on a long life as an amateur scientist and as a critic of non-Euclidean geometry/cosmology. You: My beef with ‘time dilation” is that it appears to reify time, as if “it” were ‘something’ that expands/dilates. So I speak of event duration of physical processes to clarify what time means. I agree with your statement, "'time dilates' is just shorthand for clocks (and all observable processes) moving slower.” Also, when “it” is “woven together with space” to make “ the fabric of spacetime” then both are reified into a malleable medium. When you say, “that metre sticks for one person will sometimes measure time for another, and clocks in one frame measure distance in another.”... you seem to subscribe to this ‘fabrication.’ Of course the speed of light is well used as a ‘measuring stick’ for distance, as in “light minutes/years.” But that is clearly distance traveled in a specific duration of time. The debate over “spacetime” is still in full swing, as my spacetime ontology thread illustrates. Yet again, my argument for objective realism assumes that “Real world objects don't change with measurements from different frames of reference,” Given the above argument for what time is (and isn’t), there are no local time environments or local present/now environments. It obviously takes time for light to travel from 'there to here,' but now is now everywhere. Need we re-define "is," or is that a clear enough definition? If not, please explain whatever boundaries you see around time or “now” (this instant) that make 'it' local. me: “Earth is geometrically a 3-D near-sphere.” You: “No it's not. A slice of Earth at any given time is a near-sphere.” Again, given my “real world objects” statement above as a basic assumption of objective realism, “slicing” it and/or measuring it from Pluto does not change its intrinsic, nearly spherical shape, nor does flatly denying the extremely well established earth-science description of it. You: “If you slice it right you can get an oblate sphereoid.” Maybe you are so into the model/theory that you don’t see that theoretical ”slicing” to “get an oblate spheroid” doesn’t actually make it an oblate spheroid. Rather, you seem to believe that frames of reference create reality, and that there is no objective reality independent of measurement from different frames of reference. (Idealism.)

First a "process" note: By the nature of such a forum, my discussions with swansont on "no preferred frame of reference" as a form of idealism, and with Cap 'n R on what time is and the meaning of SR theory (aside from the math) will likely get swept under the rug by subsequent replies and replies to replies. I hope that doesn't happen here as I go ahead and reply to the immediately above. TAR: The Wiki quote on objective idealism said, "...only one perceiver, and that this perceiver is one with that which is perceived." "Only" makes it theistic, whether mono- or pan-theistic. Objective realism does not require "god" to posit that the world/cosmos is real all by itself, independent of observation and measurement. The relevant question is then, how can science best investigate that reality? It is obvious to me that the scientific method must minimize unknown variables as best it can. That means, to me, at rest with what is observed, or as close as possible to that, not via the notorious near 'C' fly by frame relative to the object investigated. A fine sentiment, but those who claim that a nearly flattened earth is just as correct as a nearly spherical earth (etc. with a very shortened AU or meter) are not correct. It requires a belief in an obviously absurd and experimentally unverified dogma, length contraction, to make two drastically different versions of earth's shape "equally true." Schrodinger's hat: Saying so doesn't make it so. I say space is 3-D volume and time is duration of travel or movement of any object through space. Check out the discussion and references in my ontology of spacetime thread. "Flat spacetime" is an invention of non-Euclidean geometry/cosmology. If it is just a coordinate system, ontology requires verification of the "real territory" to which "the map" refers. Euclideans see "flat" as describing a 2-D plane. Alllength contraction advocates here are saying that a very out of round earth is just as "real" as a nearly spherical earth, because it all depends on frame of reference, and none is "preferred" over another. Measurement of a meter rod as 12 cm is wrong, due to the error of measuring it while passing by at near lightspeed rather than stopping and coming to rest next to it. (Not saying that Lorentz transformation formula does not have useful application for "transforming" the observed 12cm measurement to the 100 cm that the meter is intrinsically, as an "objective" object in the real world. Well, either earth stays about 93 million miles from the sun (give or take in its elliptical orbit) or it varies to as little as 12 million miles, as seen from a high speed frame of reference. If you believe that such variation in the AU is "real" then you subscribe to the version of idealism that insists that reality Is as it appears from any/all frames of reference, no matter how extreme, short of full lightspeed. Any games with geometry you propose must answer to the above, as well as to the fact that earth can not be both shapes, as above. It is, in fact, not a very oblate spheroid, but nearly spherical. Here is your mind game vs the real world: Earth is geometrically a 3-D near-sphere. In the real world, space is 3-D (1-D = a line; 2-D = a plane; 3-D = volume = space.) And time is "that which elapses" as things move through space. Amazing! If earth were a flat circle and you turned it on edge... it would look like a 1-D line. (No argument.) For sure! Starting with earth as a flat circle. To be brief re: Time is how long it takes something to go from A to B in 3-D space. Real world objects don't change with measurments from different frames of reference, including looking at them at different times (discounting things like watching a tree grow or the earth getting 'fatter' over eons of spinning.) me: You: You are clearly unfamiliar with ontology, which does ask "What is time?" and will not accept the above tautology as an answer. We can observe clocks slowing down at high velocity, but we can not observe "time" slowing down, or "dilating." Then the question becomes, "Why do clocks slow down at high velocity?', not "what is this thing/medium/whatever that "dilates?" Time is not 'like' electrons. You can't point at "time", but you can identify the energy shells in the elements which are composed of swarms of "electrons." Not an appropriate similarity. Gotta go.

Philosophy of science examines its basic assumptions, the focus of this thread. Is the world as-is, in- and- of- itself and all its parts, independent of observation/measurement (objective realism);... Or is there no physical "reality" other than how we see the world (idealism; frame of reference determines reality.) Just so you understand the philosophical issue at hand here. As far as I know, all scientists except advocates of length contraction describe earth very precisely as very nearly spherical, an AU remains about 93 million miles even when (if) viewed as an eighth or so of that from the overworked extreme frame we've been discussing; and a meter remains a ten millionth of the surface quadrant of earth, equator to pole, even when a near 'C' frame sees it as about 12 cm. Here is a little review of the ontological question, "What is time?" from my other threads: Marat, post 7, Ontology of Time: I agree. As events happen, we can measure their duration and assign conventional "time units" by which clocks are calibrated. Do you disagree, Cap ‘n? If so, how so? On my understanding of SR, Ross: (My bold) I understand very well what the conceptual components of SR are. Deiks on spacetime (that it is debatable, not a given, as you use it): Deiks summarizes this debate as follows: (my bold again) From ontology of time, starting with my post 50: Cap ‘n R (same thread): Do you realize that it is a meaningless tautology to say that “Time is that which clocks measure?” ("Time is that"... that what but duration?) As an event is happening (any physical process) we can measure its duration by the elapsed time on a clock (adjusting for the effects of velocity, gravity, etc., as needed.) The clock measures the time it takes for actual processes to happen. From Lysa Zyga, quoted in post 51, spacetime ontology thread: Comments? (I'll be gone for the weekend.)

me: "There is such a thing as the real earth, which does not depend on how that traveler sees it?" Cap 'n R; "Yes." Then it is as it is regardless of frame of reference, as per objective realism. Cap 'n: I understand 3-D space as I've laid out the dimensions many times. I understand time as the duration it takes things to move, however far, however long it takes. So what does "through time" mean but the duration of travel from A to B? You: ... Referring to my: You missed the central point, in bold above. That does not contradict the first sentence. My space buoy was ejected from your moving object and retro-jetted to lose all the velocity it had while moving with the object, therefore becoming a stationary reference point relative to the object, which is still moving at the same velocity. This was suggested as a reality check for your assertion that, once you are on that object, it has no velocity, which is true relative to you, along for the ride, but not now relative to the buoy. You go on to say: Fine. Riding the object, at rest with it will be the best frame from which to measure and describe it. My point was that it is still moving away from (relative to) the ejected buoy, and as time passes (seconds tick away) it moves further from the buoy without making some entity out of time. Of course it is not moving relative to you, its passenger. You: I objected to your using a concept that is still in hot debate as if it were a given as part of your explanation. To my "what is time": "A dimension." How is the elapsed time between two clicks of a stopwatch (just to simplify) a dimension? It is the duration of any designated physical movement, yes? If you insist on calling that factor a dimension, fine. "No?" Just because you can specify how many seconds in a day and days in a year, a day is no longer one full revolution nor a year one full orbit? So real world referents are no longer relevant to passage of time? This should not surprise me considering that spacetime, (for example) works as a mathematical coordinate system without any ontological concern for what it actually is, if anything, in the "real world." (See ontology of spacetime thread.)

Cap 'n R: Like any other honest scientist (non-pro though I am) I have studied the real-world referents and phenomena which relativity addresses, and, like many others frequently cited in my ontology threads, I find good reason to disbelieve that a flattened version of earth or a shortened version of the AU or the meter rod (which, by consensus have no direct experimental evidence to support them) are equally as correct as the well established standard science textbook versions versions of earth, the meter and the AU. I will patiently await your answers to my recent questions.

This thread is in the philosophy section for good reason. The gist of this thread’s argument, from my last post: If you agree that earth (etc.) does not drastically change shape, then it stays the same shape. The same principle holds for lengths and distances between objects (in the "real world", assuming perception/frame of reference does not create reality.) Reality does not depend on how you look at it. If you agree, then you must accept the position of objective realism that earth (and objects, and their spatial relationships) have intrinsic properties not dependent on point of view (frame of reference.) Of course, the task of science then is to find out what those properties are by minimizing error in the process of investigation. (Again, I advocate the at-rest frame with whatever is investigated as introducing the fewest unknowns and error.) If you disagree, then you accept some version of idealism, which says that various shapes (diameters, etc) of earth and other objects, and distances between them are equally valid, based on the rule that "there are no preferred frames of reference.” I believe that this dictum constitutes a dogma in disservice to open and unbiased scientific investigation. It is pretty simple really. Relativity’s length contraction is based on a form of idealism which denies an objective universe with properties independent of measurement and observation from different frames of reference. The rest is quibbling over details. Yet I will address some of the recent arguments against the above (soon.) Cap 'n R, Some unanswered questions: Do you agree that, "There is such a thing as the real earth, which does not depend on how that traveler sees it?" Cap 'n R: * from any point A to point B. In "the real world," if an object is moving at constant velocity, a virtual coordinate marker (or actual space buoy) could be ejected and retro-jetted to lose all inertial velocity it had with the object (become stationary relative to the object.) This would serve as a 'reality check' to your "In its perspective, it's stationary..." I see "time" as event duration of (any) physical process (EDPP.) Since everything everywhere is moving, there is no case in which time does not elapse at all (unless considering a virtual instant in the ongoing NOW.) Time is not some entity interwoven with another dubious entity, space, according to all criticism of spacetime. Please address my recent comments on the ontology of spacetime, and immediately above, questioning 4-D space. You constantly assert,"Spacetime is four dimensional", as if the whole debate among scientists and philosophers of the International Society for the Advanced Study of Spacetime is over and it's advocates won. this is not the case. (Again, see my spacetime ontology thread and references.) Then you assert that time is not the duration of such an event as movement of an object from point A to point B, as I contend. Do you "win" without an argument, or will you explain what you think time is? Isn't a day one revolution (the spinning movement) of earth and a year one orbit, movement around the sun? (See my "ontology of time" thread if interested in the argument on what time is.)

You continue to assert “spacetime” as a given without having addressed any of the criticisms of it presented in the ontology of spacetime thread. If you refuse to engage in discussion of what spacetime is, then we can not have a conversation about it as if non-Euclidean geometry and Minkowski’s spacetime were not an issue, as you seem to assume. I have posted a lot on the assumptions inherent in the transition beyond Euclidean 3-D space and time as merely the movement factor. (Obviously it takes time for things to move around in space even with space as simply volume described by three axes.) An interval is elapsed time for any physical movement through 3-D space. How do you see “the spacetime interval” as four dimensions if different from that, i.e., if not a fourth spatial dimension, which I have often challenged? In other words, what does “four-dimensional length” actually, ontologically* mean? (*Referring to the objective world.) How do you explain this four dimensional length? Please present a cogent argument against the following: Length is one dimensional, a straight line from one point to another. A plane is area, with two dimensions. Space (volume) is three dimensional. Time introduces event duration of movement from one point to another through space. (Please, no lectures on intrinsic vs extrinsic curvature relative to different mental models or conceptual “manifolds.” Have you even looked at the Kelley Ross paper on all of that?... The Ontology and Cosmology of Non-Euclidean Geometry.) To your last question: The closest form of that philosophy that I know of is called “objective idealism,” which I have called an oxymoron because realism as objectivity and pure subjective idealism are mutually exclusive. But there is a 'gray area’ explained by the following entry from Wikipedia on Objective Idealism: “One perciever” is clearly theistic, and I dismiss it. But my first emphasis in bold addresses your question. The second bold emphasis requires the explanation I have repeatedly provided: That *the properties of material objects* (not denying the objects per se) exist independently of frames of reference, even abstract ones, not insisting on human perception. Finally, the most common metaphor for your "reality is real, but we all see different parts of it"... is of course the old saw about the three blind men and the elephant. From one 'frame of reference' it is like a tree trunk. From another, a fire hose. For the third, a rope. (Leg, trunk and tail. I guess none of them felt the belly or climbed on top.)

Cap ‘n R: I wouldn’t call my rejection of spacetime “rash.” I’ve studied criticisms of it for a few years now. (See references in the ontology of spacetime thread.) And again, my argument is that changing coordinates (frames of reference) does not effect the intrinsic properties of objects observed. So when you say, “for a high speed traveler, earth is an oblate spheroid,” that does not mean that earth *IS* such. Here is a diagram of the sentence; Independent clause (primary sense of the sentence); ..."earth is an oblate spheroid." Dependent clause (condition under which the primary sense is true): "for a high speed traveler." So the above condition makes the earth an oblate spheroid. False. There is such a thing as the real earth, which does not depend on how that traveler sees it. If you disagree, you are a subjective idealist as presented in contrast to objective realism in this thread. If that is the case, I have made my argument. Swansont: My logic compared what we know about incoming natural muons to lab muons, i.e., longer lifespan, and then explained that traveling further through the atmosphere than expected, because of that does not mean that the atmosphere is shallower (length contracted) because of all of the above. “For a muon” grants a point of view to a muon which contradicts the known depth of earth’s atmosphere. If that happens to be ridiculous, (which it is) it is not that my ridicule makes it so. You say the following is not true... “Repetition doesn't make this true.”: (me) If you agree that earth does not drastically change shape, then it stays the same shape. It does not depend on how you look at it. If it stays the same shape, what shape is that? (Multiple choice): Nobody knows. Nearly spherical, as per the mountain of empirical evidence from earth science, from at rest frame. Severely oblate, granting equal validity to a frame of reference flying by it at near light speed. Science (with the exception of length contraction advocates) says it is nearly spherical, not in fact a severely oblate spheroid. You can say “all of the above” but you will be wrong. You can't dress up my conditional logic as a categorical syllogism by introducing a fourth term which is not part of the argument, and pretend it is faulty logic on my part. The Wiki example is intended to show how stupid such fourth term fallacy is in a syllogism ... which it is.

swansont: You can “reword” it all you want and appeal to “protocols of measurement without error”, but since the earth doesn’t drastically change shape, it IS either very oblate or nearly spherical. In all honesty, it can not be both, in the “real world.” I have taught university level “Logic and the Scientific Method” and you are way out of your element (field of expertise) here. I don’t intend to embarrass you personally, but you have grossly misapplied the “fallacy of four terms,” which I just reviewed from your link. First I am not using a “categorical syllogism” as exemplified in your link. Rather I am using a simple conditional form of “If,... Then” logic. If my premise is true then the conclusion logically follows. First the misplaced example from Wikipedia: My argument again: (note, there is no fourth term stupidly interjected as in the above example): We agree on the premise that earth does not “morph,” does not change form drastically, the “If.” The "Then” (obviously implied) is (Then) “... it can not be both. It's diameter can not be "different lengths." My premise is consistent with the argument promoted in this thread, that objects (including earth) have objective intrinsic properties independent of the frame of reference from which they are observed (realism.) So the conclusion verifies that looking at earth from a different frame of reference will not make its diameter Be different, as in the variation of idealism where frame of reference supposedly establishes a reality in which earth’s diameter IS different. swansont; If you find fault with my “for a muon” logic (earth has a very shallow atmosphere), it is up to you to explain the fault... hopefully more cogently than above.

Cap 'n R, Please address my "airtight logic" above.

How does this address my "philosophically speaking" paragraph above? How is length contraction, derived from constant 'C', "better tested" than earth science facts? The earth; size (about 8000mi diameter) and shape (nearly spherical) is probably the most precisely measured and thoroughly studied object ever. It is rigid. It doesn't morph. It does not have a 1000 mile diameter. These are facts. How does constant 'C' invalidate them?... By a dictum that insists "all frames of reference are equally valid." Isn't "under a microscope" a more valid way to study the factual properties of a microscopic object than with it flying by at near light speed? (Ans: Yes.) (Argument for "at rest" frame with what is measured giving more valid results.) I am not arguing against the constant value of 'C', just the assumptions and conclusions of length contraction derived from it which deny the above facts. swansont: We agree that objects don’t change shape and size (in the context of length contraction.) But there is a big difference between my claim that they just look different from different frames of reference and your claim that they are different, "have different lengths in different frames of reference." Case in point, using absolutely airtight logic: If earth does not morph, it cannot change from spherical to very oblate. It must be one or the other, i.e., it can not be both. It's diameter can not be "different lengths." You guys constantly avoid the thread title question. “For” a muon, you say the atmosphere is way less than 200 miles thick. This is based on the following faulty logic: We "know” the above because incoming muons “live” longer and travel further than “expected” based on observation of lab muons, so the distance traveled must be shorter than the established depth of atmosphere. Some logic! “For” the (overworked) high speed traveler through our solar system, an AU is about 11 million miles rather than the well established 93 million miles, and earth, as above, has a diameter of about 1000 miles rather than the at-rest frame 8000 or so. “For the traveler.” “For” the same traveler passing a meter rod, it is about 12 cm long. But, of course the meter rod doesn’t change length, nor does earth’s diameter nor the earth-sun distance. All of the above perfectly fits the description of philosophical subjective* idealism, transposing "frame of reference" ("for" whatever) for "subjective." The latter says "The world is as it is perceived. It has no intrinsic properties independent of perception/frames of reference." Philosophical realism says it does. *("Subject" need not be a person but can be just an abstract point of view.) Iggy: We look at each situation in all its particulars and apply the scientific method. Your hand in front of your face was an obvious illustration. How do you "know" it is not just a palm when you can't see the back? Because, ever since we were born we have seen it from all angles and *know* it as a whole hand with all its "intrinsic properties" even when we only see one side or the other. Apply that on all scales to all "known objects." Of course, the more familiar we are with a given object the better, because we have memory and previous records as well as immediate observation as part of empirical science. Duration can be the time between the "ticks" of a clock (or "clicks" of a stopwatch) or any elapsed time of any physical process under consideration. The physical objects have intrinsic properties, as belabored above, and duration is the concept explained yet again above. As objects move we can only assign velocity relative to other objects, because that is the meaning of velocity. A car's velocity designated as 60 mph is relative to the road, but a mile-marker on the road is spinning at over 1000 mph relative to the center of earth, and the whole earth is going whatever velocity in orbit around (relative to) the sun, which has whatever velocity relative to the center of the galaxy... etc., etc... to belabor the obvious, yet again.

Backtracking to a comment by Cap 'n R last Friday: Cap ‘n R: Philosophically speaking, given a choice between the constant speed of light (with plenty of evidence for it) and the constant shape/length of 'immutable' solid objects like earth and solid rods, (with overwhelming evidence for them staying solid, not morphing out of shape or changing lengths) why is it that constant ‘C’ is assumed to be correct and immutable objects are actually mutable? How does it “make physical sense” that solid objects have no intrinsically stable properties, and rather, that light, relatively quite insubstantial, has “immutable” (constant) velocity. Just asking. Iggy, I give up yet again on explaining realism, as knowing that objects have intrinsic properties vs the idealism of "things ARE as they appear" from different frames of reference. Your hand in front of your face does not in fact change shape and characteristics as you view the palm and then the back. I'm done arguing with you about it.