I know, I was joking. And it was a good opportunity to link to this (genuinely interesting) paper.
… well, mostly joking. There’s a kernel of truth there. “There are no photons” says more than just banning a word. “Wavepackets of light” don’t exist either. There’s just the electromagnetic field, its intensity changes with time, and the change propagates in space. Looking at it like this may help understand the other responses to the question (which are all correct).
When you think of a photon as a particle flying in space, it’s hard to shake off the feeling that you somehow ought to be able to attach yourself to it and come along for the ride, or to imagine how the particle itself “feels” about its existence, how its inner time passes. And then the answer that for a photon, time doesn’t pass at all, feels weird and counter-intuitive. If you tell yourself there’s no particle, just a bunch of numbers everywhere in space (expressing the EM field) and a slight change in those numbers travels down the line, it may be easier to process. A change is not an object to strap yourself to. It doesn’t have “inner time”.
By this argument, ocean waves don’t exist either. There’s only the sea, its height changes with time, and the change propagates in space.
You say that as a reductio ad absurdum, but it is good for some purposes. Anatoly didn’t claim that one should deny photons for all purposes, but only for the purpose of unasking the original question.
Anatoly didn’t claim that one should deny photons for all purposes, but only for the purpose of unasking the original question.
In this case, unasking the original question is basically an evasion, though, isn’t it?
Denying photons may enable you to unask hen’s literal question, or the unnamed Reddit poster’s literal question, but it doesn’t address the underlying physical question they’re driving at: “if observer P travels a distance x at constant speed v in observer Q’s rest frame, does the elapsed time in P’s rest frame during that journey vanish in the limit where v tends to c?”
I reject the claim that your rephrasing is the “real” question being asked. By rephrasing the question, you are rejecting it just as much as Anatoly. I think it is more accurate to say that you evade the question, while he is up front about rejecting it.
In fact, I think your answer is better and probably it is generally better to rephrase problematic questions to answerable questions before explaining that they are problematic, but the latter is part of a complete answer and I think Anatoly is correct in how he addresses it.
I reject the claim that your rephrasing is the “real” question being asked.
That multipledifferentpeople automatically treated hen’s question like it were my rephrasing backs me up on this one, I reckon.
By rephrasing the question, you are rejecting it just as much as Anatoly. I think it is more accurate to say that you evade the question, while he is up front about rejecting it.
Rephrasing a question can be the first step to confronting it head-on rather than rejecting it. If a tourist, looking for the nearest train station, wandered up to me and asked, “where station is the?”, and I rearranged their question to the parseable “where is the station?” and answered that, I wouldn’t say I rejected or evaded their query.
Problem evaded. Banning a word fails to resolve the underlying physical question. Substitute “wavepackets of light” for “photons”; what then?
I know, I was joking. And it was a good opportunity to link to this (genuinely interesting) paper.
… well, mostly joking. There’s a kernel of truth there. “There are no photons” says more than just banning a word. “Wavepackets of light” don’t exist either. There’s just the electromagnetic field, its intensity changes with time, and the change propagates in space. Looking at it like this may help understand the other responses to the question (which are all correct).
When you think of a photon as a particle flying in space, it’s hard to shake off the feeling that you somehow ought to be able to attach yourself to it and come along for the ride, or to imagine how the particle itself “feels” about its existence, how its inner time passes. And then the answer that for a photon, time doesn’t pass at all, feels weird and counter-intuitive. If you tell yourself there’s no particle, just a bunch of numbers everywhere in space (expressing the EM field) and a slight change in those numbers travels down the line, it may be easier to process. A change is not an object to strap yourself to. It doesn’t have “inner time”.
I feel I should let this go, and yet...
But we can make them! On demand, even.
By this argument, ocean waves don’t exist either. There’s only the sea, its height changes with time, and the change propagates in space.
You say that as a reductio ad absurdum, but it is good for some purposes. Anatoly didn’t claim that one should deny photons for all purposes, but only for the purpose of unasking the original question.
In this case, unasking the original question is basically an evasion, though, isn’t it?
Denying photons may enable you to unask hen’s literal question, or the unnamed Reddit poster’s literal question, but it doesn’t address the underlying physical question they’re driving at: “if observer P travels a distance x at constant speed v in observer Q’s rest frame, does the elapsed time in P’s rest frame during that journey vanish in the limit where v tends to c?”
I reject the claim that your rephrasing is the “real” question being asked. By rephrasing the question, you are rejecting it just as much as Anatoly. I think it is more accurate to say that you evade the question, while he is up front about rejecting it.
In fact, I think your answer is better and probably it is generally better to rephrase problematic questions to answerable questions before explaining that they are problematic, but the latter is part of a complete answer and I think Anatoly is correct in how he addresses it.
That multiple different people automatically treated hen’s question like it were my rephrasing backs me up on this one, I reckon.
Rephrasing a question can be the first step to confronting it head-on rather than rejecting it. If a tourist, looking for the nearest train station, wandered up to me and asked, “where station is the?”, and I rearranged their question to the parseable “where is the station?” and answered that, I wouldn’t say I rejected or evaded their query.