Brent's statement Re: parking paradox

[Alan Grayson]

We were arguing about is whether I ever changed my mind. Quentin doesn't believe I did. What do you say? More important is this: if fitting and not fitting do not happen at the same time. AG

They do happen at the same time as clearly shown on my diagrams.  In the garage frame the entrance door closes before the exit door has to open.  The car is in the garage for about 2.5 nano-seconds. In the car frame the doors are open at the same time so the car extends thru both.

Brent

[Alan Grayson]

Since you know SR well enough to know that every frame has its own clocks and its own time. Consequently there's no single same time ("They do happen at the same time ... ")  for the car and garage frames to share. That being the case, I'd appreciate your interpretation of your words above. TY, AG 

[Alan Grayson]

Brent; if you have time please reply to above question. 

My likely last word on the parking paradox problem. As Clark posted, the paradox exists if one assumes the car fits and doesn't fit AT THE SAME TIME. Of course, this is not a realistic scenario in SR, since it assumes the car and garage frame share the same clocks. But they don't. And the proof of that is the disagreement on simultaneity. So, IMO, using this disagreement just shows that fitting and not fitting cannot occur simultaneously. However, also IMO, it really doesn't resolve the paradox which doesn't simply depend on contradictory events occurring simultaneously. It depends on relaviity showing that the car can and cannot fit in the garage regardless of the time this occurs, and this prediction surely seems inherently contradictory even if predicted by SR. 

AG

[Quentin Anciaux]

AG, your "last word" is just another rehash of misunderstandings wrapped in feigned profundity. Let’s address it directly:

1. "The paradox exists if one assumes the car fits and doesn’t fit at the same time":

This is not the paradox at all—it’s a strawman. The frames disagree about whether the car fits due to their differing simultaneity, which is exactly what special relativity predicts. There’s no shared universal time or clock between frames, so no contradiction exists.

2. "Disagreement on simultaneity just shows fitting and not fitting cannot occur simultaneously":

Correct, and this is the resolution. The frames disagree on the timing of events, which fully explains why one sees the car fitting and the other doesn’t. This disagreement is the heart of relativity, not a flaw.

3. "It really doesn’t resolve the paradox":

Yes, it does. The so-called paradox is fully resolved when simultaneity is accounted for. If you’re still clinging to the idea that there’s some deeper contradiction, it’s because you’re stuck on pre-relativistic notions of absolute time and space.

4. "It depends on relativity showing the car can and cannot fit regardless of time":

No, it doesn’t. Relativity shows that the car fits in the garage’s frame and doesn’t fit in the car’s frame, with both perspectives being valid within their own simultaneity. This is not contradictory—it’s precisely how SR works.

What "surely seems inherently contradictory" is only so because you refuse to fully grasp how relativity dismantles classical intuitions. The paradox is resolved; the only thing that persists is your refusal to let it go.

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[Alan Grayson]

On Saturday, January 18, 2025 at 8:53:14 AM UTC-7 Quentin Anciaux wrote:

AG, your "last word" is just another rehash of misunderstandings wrapped in feigned profundity. Let’s address it directly:

I'm not feigning anything. We just disagree and you find that intolerable. AG 

1. "The paradox exists if one assumes the car fits and doesn’t fit at the same time": 

This is not the paradox at all—it’s a strawman. The frames disagree about whether the car fits due to their differing simultaneity, which is exactly what special relativity predicts. There’s no shared universal time or clock between frames, so no contradiction exists.

Yes, this is the root of the paradox, as Clark claimed; the assumption that the car and garage frames share the same clocks. And I don't claim they do. AG

2. "Disagreement on simultaneity just shows fitting and not fitting cannot occur simultaneously":

Correct, and this is the resolution. The frames disagree on the timing of events, which fully explains why one sees the car fitting and the other doesn’t. This disagreement is the heart of relativity, not a flaw.

I see it as indicating a possible flaw in SR. And last I heard, I am entitled to my opinion, but maybe not in Belgium. AG 

3. "It really doesn’t resolve the paradox": 

Yes, it does. The so-called paradox is fully resolved when simultaneity is accounted for. If you’re still clinging to the idea that there’s some deeper contradiction, it’s because you’re stuck on pre-relativistic notions of absolute time and space.

AFAICT, nothing to do with any notions of absolute time and space. AG 

4. "It depends on relativity showing the car can and cannot fit regardless of time": 

No, it doesn’t. Relativity shows that the car fits in the garage’s frame and doesn’t fit in the car’s frame, with both perspectives being valid within their own simultaneity. This is not contradictory—it’s precisely how SR works.

Sounds like you're a True Believer. AG

What "surely seems inherently contradictory" is only so because you refuse to fully grasp how relativity dismantles classical intuitions. The paradox is resolved; the only thing that persists is your refusal to let it go.

I think I grasp the theory well enough, if not perfectly. As I wrote, I am entitled to my opinion, and you are entitled to yours. Now do me a favor and don't respond. AG

[Quentin Anciaux]

AG, you don’t get to throw out baseless accusations, misunderstand core concepts, and then demand no response. If you genuinely believed in the value of your "opinion," you wouldn’t need to constantly dismiss valid explanations as the ramblings of a "True Believer." Let’s be clear:

1. The "root of the paradox": The disagreement in simultaneity isn’t the "root of the paradox"; it’s the resolution. The paradox only exists in the mind of someone who insists on applying pre-relativistic intuitions to relativistic phenomena. You say you don’t claim shared clocks, yet your reasoning keeps circling back to implicit notions of universal agreement.

2. Your "possible flaw in SR": You’re entitled to your opinion, but opinions without evidence or logical consistency hold no weight in scientific discourse. SR has been rigorously tested and confirmed; if you’re going to call it flawed, you need more than "it feels contradictory to me."

3. "Nothing to do with absolute time and space": If it doesn’t, then what exactly is your objection? Relativity’s predictions and resolutions rely on the dismissal of absolute time and space. By denying this as the source of your discomfort, you’re refusing to engage with the actual foundations of SR.

4. "True Believer" dismissal: A cheap shot to avoid addressing the explanation. Understanding a well-supported scientific theory isn’t "belief"; it’s acknowledging evidence and logic. Refusing to grasp it isn’t skepticism—it’s obstinacy.

If you really want no response, stop responding yourself. But deep down, you know you don’t actually want the last word silenced—you want it to validate your misconceptions. That won’t happen here.

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