Iggy

Kant disproved the ontological argument in exactly that way. A jump is made from thought to reality. Kant here objects that being or existence is not a mere attribute which may be added on to a subject, thereby increasing its qualitative content. The predicate, being, adds something to the subject which no mere quality can give. It informs us that the idea is not a mere conception, but is also an actually existing reality. Being, as Kant thinks, actually increases the concept itself in such a way as to transform it. You may attach as many attributes as you please to a concept; you do not thereby lift it out of the subjective sphere and render it actual. So you may pile attribute upon attribute on the conception of God, but at the end of the day you are not necessarily one step nearer his actual existence. So that when we say God exists, we do not simply attach a new attribute to our conception; we do far more than this implies. We pass our bare concept from the sphere of inner subjectivity to that of actuality. This is the great vice of the Ontological argument. The idea of ten dollars is different from the fact only in reality. In the same way the conception of God is different from the fact of his existence only in reality. When, accordingly, the Ontological proof declares that the latter is involved in the former, it puts forward nothing more than a mere statement. No proof is forthcoming precisely where proof is most required. We are not in a position to say that the idea of God includes existence, because it is of the very nature of ideas not to include existence. Wikipedia - Critique of Pure Reason - Refutation of the Ontological Proof of God's Existence With one caveat -- abstract reasoning does prove the reality and the real existence of the reasoner -- because, you know, I think therefore I am. False dichotomy. Earth is spherical (in its rest frame) and its shape depends on frame of reference. It's like asking "is it raining today or is it dry and sunny depending on location?" Yeah, it is "raining today" (here) and it is "dry and sunny depending on location". It's equivocating, just like... If "change" and "morph" refer to changes over time in a single frame and "different lengths" refers to differences between frames then it's a false dichotomy... but it's an amphiboly so who could say. Even after people point this out, Owl, you keep doing it. I would be embarrassed.

I'm sorry if you feel like people aren't paying enough attention to you, but you in fact did not say "relative to both sun and earth". You didn't say what the velocity was relative to, and that's why I asked. I would assume it's why Schrodinger asked as well. But, if distance and duration are constant (i.e. the same in all frames) then that cannot be. It is a small matter of deduction to prove this. The blue planet has a velocity relative to the green planet. The lines mark distance. Fill in some numbers. Try showing that the red arrow, the light, has the same speed relative to both planets. It obviously can't. The change in the length of the red line over time is the speed of light relative to the blue planet and the change in the length of the green line over time is the speed of light relative to the green planet. They can't be the same. Without time dilation and length contraction you just have classical mechanics -- in which the speed of light is not constant. This should literally be the first thing you learn when learning relativity. You missed my point. I guess I should explain in more detail. To your assertion that stars and planets take on their oblate spheroid shape "due to the well known laws of physics", and that it is somehow separate from relativity, it should be pointed out that general relativity is that well known physics. Newtonian physics, including Newton's law of gravitation, is different from relativity -- it makes different predictions. Where those differences have been tested the results support general relativity and disagree with Newton's system. "for ages"? Earth becomes more spherical over time.

Could you answer Schrödinger's question, please? If "velocity requires specificity as to 'moving how fast relative to what'", and its speed is "186,000 mps", then *with respect to what* is that its speed? By refusing to say, you are directly contradicting yourself. The best explanation for the bulging spherical shape of planets and stars is general relativity. A rotating gravitationally bound object has a surface of constant potential making it a surface of constant proper time.

Think of it this way, Tar... Two people who are floating away from each other at great speed in deep space can each measure the speed of the same ray of light and get the same answer... 300 thousand meters per second (or whichever units you like)... as Schrodinger says... So, as an analogy... Imagine someone standing in the street watching a bus drive away from them. They measure the bus move away from them at 60 miles per hour. Every hour the guy in the street notices that the bus is another 60 miles away from him. Someone else is driving in a car chasing the bus. They drive their car 58 miles per hour relative to the guy standing in the street. The person in the car measures the speed of the bus relative to himself and gets 60 miles per hour. Every hour the guy in the car notices that the bus is another 60 miles away from himself. Someone else is driving a car in the opposite direction. They drive their car 50 miles per hour relative to the guy standing in the street. This person measures the speed of the bus relative to himself and also gets 60 miles per hour. Every hour this guy finds that the bus is another 60 miles away from himself. Everyone, no matter how fast they are going in either direction on the road, measures that the bus moves 60 miles relative to themselves each hour. In this analogy the speed of the bus, 60 mph, is constant. In our world 300 thousand km/s is constant.

Perhaps in the recesses of your mind exits a fantastic vault of reasoning supporting your belief. But, I can't help notice, you've failed entirely in expressing it. Could you, again, try giving one reason why (never mind a "good reason") distance should be constant and not relative? Once you do that, and, again, you have completely failed thus far -- All of your work is still ahead of you! You must then apply that exact same reasoning to the concept of velocity (or momentum or any other property you've picked out of the frame-dependent hat) and come up with an entirely different answer. I'm holding my breath in anticipation.

If earth is spherical at one point in a frame of reference then it is spherical at all points in that frame of reference. At no point is it not. The method of observation shouldn't matter. The method of measuring distance shouldn't matter. Whatever works. Correct. If there is a speed, less than infinity (call it "c"), that is the same no matter how fast one changes their point of observation then it should matter very much.

A good answer. You know it because you see it every day. In order to deal with the world your mind is programmed with an intuition about what to expect of the world. Your mind expects objects to maintain their dimensions no matter how you rotate the object. There is no preferred direction in space. This is correct and intuitive to you because, as a human, you have to deal with it on a day to day basis to survive in the world. But, you are now dealing with a subject which you, personally, have never dealt with in your life. You have no intuition upon which to draw -- nor should you expect to have an intuition of length contraction, time dilation, and the relativity of simultaneity. You again didn't answer why you should expect duration to be intrinsic and not relative to frame of reference, but I haven't expected you to answer. The truth, Owl, is that you don't know why you expect that. You don't know why you claim it as a fact. You have no information upon which you have drawn that conclusion and no reason to expect having any intuition of it. It's quite clear you are just guessing and you are guessing wrong. The duration between two events (between a plane taking off and landing, for example) is not constant. It is different in every different reference frame just as much as velocity is different in every different reference frame. Hafelle and Keating proved it and GPS systems are programmed to "know it" or they couldn't do their job. If you regularly judged duration in terms of nanoseconds or if you accelerated a significant fraction of the speed of light every day then you would have an intuition of it too. But you don't, so if you want to keep talking about the fact of this matter then stop expecting things to be true for no reason at all. Stop expecting your intuition to tell you the truth. It's not going to help you.

The question was, how do you decide if a property is intrinsic or not. Why is duration intrinsic and velocity not? You keep saying that's the way the world is and that's the way it has to be. Have you asked yourself why?

Counterexample.

Nothing of that is inconsistent with special relativity. That is not presentism. On the grounds that everything is moving and velocity requires specificity as to "moving how fast relative to what."(as I've said a few time already.) Whereas, (as I've also repeated many times) realism posits that objects have intrinsic properties like shape, size, density, rigidity, etc., independently of how (or if) they are seen from whatever FOR. Likewise, the distance between bodies, is also intrinsic as above, depending only on their movement relative to each other (closer or further away), i.e., one AU or about 93 million miles between earth and sun. This does not change just because a high speed traveler might see that distance as, say 1/8th the standard AU. That would mean that perception creates reality, the idealist belief, contradicting the realism that insists that the only variation in that distance is due to the irregularity of the elliptical orbit, sometimes closer, sometimes further. It is difficult to tell if you are purposefully not answering or if you do not understand what I am asking. Let's try this. Get a piece of paper and draw a line down its center. Label the left side of the paper "constant, frame independent, intrinsic properties". Label the right side "relative, frame dependent, non-intrinsic properties". Now write these words on the page wherever you think they belong... on the left side or the right side: distance, velocity, size, duration, color, momentum. The question is *how did you decide* where to put the words. In each case, how was the decision made? If you think that realism demands that certain words go on the left or right then, why? Why do you think realism demands velocity on the right, but demands duration on the left? So far all you have said is that velocity is relative because velocity is relative and distance is constant because distance is constant. That doesn't get us anywhere. According to SR and the thought experiment you laid out you wouldn't have to.

It may be important to note that the events themselves are not in transit. The light emanating from them is. I don't know of any specific label to give the category of events you outline. They are events that were in your present instant at some time in the past.... which is, I suppose, a drawn out way of saying that they are in the past. Those events could also, interestingly enough, be in your present instant again if you took on a sufficient velocity away from Alpha Centauri. You could google "Rietdijk–Putnam argument" if that sounds of interest. I share Owl's concern, however, that we've gotten a bit beyond the topic at hand. I understand your position. There is no point in repeating it. You say that velocity is relative to reference frame. I assume you would say the same thing of momentum and a few other frame-dependent properties. But, distance and duration, you say, can't be relative. This begs a very obvious question... On what grounds do you choose which properties can and cannot be relative? Why does it imply subjective idealism to say "distance depends on frame of reference" and it does not imply subjective idealism to say "velocity depends on frame of reference"?

Yeah, I understand what you're saying. One set of events are observed now and the other happen now. The first relativity calls your past light cone and the second it calls the present instant. By your silence I assume I'm correct -- because you say velocity depends on reference frame you have thrown out philosophical realism and subscribed to a form of idealism in which objects have no intrinsic properties.

So when they say mass curves spacetime they mean it curves a coordinate system, a map? What curves in the real world... is the ontological question, which has not yet been addressed. Yes, it curves a coordinate system. The coordinate system represents what clocks and rods measure. A "clock" is any regularly repeating physical process. What is "duration"? What is an "event"? You couldn't define "velocity" either. What is Euclid's fifth postulate and how have you proven it correct when hundreds of years of mathematicians have failed at that task? What would a "referent in the real world" of a violation of Euclid's fifth look like and how have you proven that there isn't one? "Speculations must be backed up by evidence or some sort of proof."

Do you have a scientific theory that suggests these things are true? Einstein, on the issue, said: When Einstein says that his theory proves something we should probably give that quite a bit of weight.

Not that I've heard of. At larger and larger scales, homogeneity is a better and better approximation. When it becomes a 'good' approximation would very much depend on how good of an approximation you need... which would be situation specific and not something that could be declared in general.

The reason it is not universal is that it is not shared by multiple frames of reference. Two people who have a relative velocity do not agree on which events happen 'right now'. I understand what you mean. I saw you talking about it earlier. All of the events that happen 'right now' or 'at the present instant' happen simultaneously -- or at the same time. Saying "right now" is another way of saying "at this time". If the current time is 4:00 am then all the events which happen 'right now' happen at 4:00 am. You are, of course, correct -- a person will not see all of those events straight away. An event that is one light-second away will take one second before it is seen. An event that's one light-year away takes a year before it is seen. This is not a problem because 1: light has a finite speed, and 2: we are talking about when events happen, not when they are observed. In fact, these are two separate events we're talking about. When a star goes supernova several light-years away that is an event. When humans observe the supernova that is another event. The supernova event and the observation event are separated by space and time. They are different dots on a space-time diagram. In relativity "simultaneous" refers to time. Two events that are simultaneous will be seen by an observer half way between them at the same time. This is the way Einstein defined the term. It is also, by the way, the way St. Augustine defined the term fifteen hundred years ago. He said that two women who are separated by a great deal of distance would have given birth simultaneously if messengers sent out at the moment of delivery met up midway between the two women.

I've read the blog you're talking about. It calls relativity a "metaphysically elegant theory" and disagrees with all of your objections to intrinsic curvature.

I think you make a good point. But, I believe homogeneity is a typical simplifying assumption with this type of thing -- even at quite small scales. The Jeans length for example, is often applied to molecular clouds and other relatively small things. I agree. That is a good counterexample.

Because you say that velocity depends on frame of reference, you have thrown out philosophical realism? Can't answer? The speed of light, the space-time interval, and a host of other properties do not depend on frame. "no intrinsic properties... independent of frames of reference" is a strawman, and you've already been told this.

Besides disregarding the cosmological constant, it is model independent. A somewhat comprehensive description can be found on Ned Wright's Cosmology Tutorial - Part 2 with the paragraph that begins "We can compute the dynamics of the Universe". If you want to know if an area of space will eventually collapse or continue to expand indefinitely, mark the area as a sphere. Measure the radius of the sphere -- [math]r[/math], and the velocity of the edge of the sphere compared to the center -- [math]v[/math], and solve: [math]\frac{3 \left( \frac{v}{r} \right)^2}{8 \pi G} [/math] That will be the critical density. If it is greater than the measured average density of the sphere (mass / volume) then it will continue to expand.

As far as my point is concerned, it doesn't matter if something was sent from A to B 10 years ago or 10 minutes ago. The point is to counter Owl's claim that *only* things at rest to the thing being measured will measure distance accurately. In fact, something at rest can't measure distance at all. When the measurement happened is really beside the point. I can't quite make sense of this. Space-time spans time. Measurements of it made yesterday, today, and tomorrow, are all measurements of the same space-time. That is a fantastic point!... especially in terms of the ontology of time. For humans to understand perception they categorize data in terms of space and time. Kant called time a category. This means, according to Kant, that an object cannot be experienced unless it has the property of time -- or, put more correctly, it can't be experienced unless the thing experiencing it has an a priori category of time in which to organize the perceptive data of that object. I think this has significant philosophical implications. I wouldn't say they make it into something that it is not. I thin we can put this into the language of philosophy easily. Humans have three complimentary intuitions that are pertinent to what we're talking about: space, time, and movement. What is at issue here is the relationship between the three. Does the amount of space and the amount of time depend on movement. Intuition says no, but relativity and observation says yes. This doesn't mean that time, space, and movement are *not* categories like Kant believed they were -- that they make it something that it is not. It just means that the three categories work a little different than intuition would expect. A good answer to this is found on this page with the paragraph that starts "The question that may be raised in philosophical cosmology is whether this cosmic time constitutes an absolute time..."

Owl wasn't talking about the perspective of light, and length contraction and time dilation equations don't apply to light (although this is a typical misapplication). To say that light experiences no time or space is to apply equations outside of their boundary. I would say more, but I don't want to venture off topic. Anything that moves from A to B can't be at rest relative to A and B -- this was my point. You can't measure [math]\overline{AB} [/math] without sending something from A to B.

I believe you. No, you are either obfuscating, mistaken, or lying. You were replying to something really rather simple: Your answer was also rather simple: "at rest" means "zero velocity". Are we on the same page now? Earth, according to you, doesn't have a single velocity. It has zero velocity according to one frame of reference and a great deal of velocity according to another. By your reasoning: earth changes its velocity, does it not? How is this not, again by your reasoning, subjective idealism? Do you think a person's perspective changes the velocity of an object? If you don't believe perspective changes velocity then you must believe earth has a single, unchanging, immutable, intrinsic velocity. Either earth has a single absolute velocity, or you are (by your own understanding of the term) a subjective idealist. So, which is it? 1. Earth has a single velocity that does not depend on various points of view. 2. Earth's velocity changes with perspective. <edit>I should add... it is, of course, entirely agreeable that velocity is frame dependent. The implications attributed to frame dependent quantities by Owl are disagreeable (eg they are subjective idealism)</edit> No, Minkowski space-time is not "simply three spatial dimensions (line, plane, and volume) and time". You could describe space-time that way, but Minkowski space-time is a specific instance of space-time which is different from other space-times. For example, Minkowski space-time has a metric signature (+---) (or -+++ depending on sign convention) and Galilean -- a Euclidean space-time -- has a metric signature (++++). Minkowski's metric signature preserves time-like, null, and space-like vectors under Lorentz transforms where the other does not. This means a time-like vector is always time-like in Minkowski space, and the same with null and space-like vectors. This is important because preserving a null vector is the same as saying "the speed of light is constant". This was the point of my previous very lengthy and laborious post. The speed of light is constant in Minkowski space-time while it is not in classical space-time.

I also would have guessed limestone... dolomitic limestone (it reacts weakly to acid). Can't really tell from the pic though. ... edit... "dolostone" might turn up a better search than "dolomitic limestone" ...edit...

Velocity is relative... that is interesting... are you saying that an object's velocity changes from one frame of reference to another? The earth's velocity changes? If that is the case, why do people not fly off the surface into deep space when the earth's velocity changes from zero to near the speed of light?