Your thinking about it also wrong: whether or not absolute zero is actually practically achievable has zero bearing on whether or not it is the coldest possible state in the universe, which it is.
See, as jothki pointed out, this is a very problematic statement you are making. If it is impossible, how is it then possible? This seems to be a rather stark contradiction, perhaps a failure to meaningfully distinguish imagination from observation/reality (often a cause of failed truth). Perhaps you are saying that it is a well-argued lower bound on possible temperatures? Ok, but that does not make it a possible temperature itself. In simple terms, what coolant could you use to cool something to 0K? Wouldn't that coolant have to be below 0 in order to cool something to 0? Absolute zero only exists as a point on a graph at which any amount of any gas would be expected to shrink to a volume of size zero. Presuming it didn't condense to liquid first... which they all do at some point above zero. So again, there are a trunkfull of reasons to question the nature of "truth" with respect to absolute zero.
You can't cool something to absolute zero. There's a proof showing that no process can be devised which reduces a system to absolute zero in a finite number of steps. You can get down to a few pico-Kelvins using laser cooling, though. Coolants stop being useful in the tens of Kelvins range, so cryogenic systems operating below that level use mechanical methods like diffusion pumping or magneto-optical trapping.
Absolute zero also has nothing to do with gases or state graphs. It's the temperature of a system with minimum entropy. A collection of molecules at absolute zero wouldn't have a volume of zero because the minimum entropy state of the system isn't a singularity.
I'm always confused by your 'observation is reality' stance. There are plenty of things in the universe that we either don't have the technology to directly observe or have reason to believe that such technology can't exist. Are none of them real? We can't send a probe into the center of the sun, so is there just nothing in there?
Interesting. Truth only matters if someone wants to live correctly. Truth has different definitions by everyone and every religion. I have an opinion, but I'm not going to say. The key is to look at what is most authentic, I think.
Interesting. Truth only matters if someone wants to live correctly. Truth has different definitions by everyone and every religion. I have an opinion, but I'm not going to say. The key is to look at what is most authentic, I think.
What does authentic mean here?
I guess I mean it as a synonym for original, what existed at first or what is attached and descended from that which existed originally.
We all seem to be using the word "true" without any sort of difficulty. What sort of definition are you looking for?
LoserForHireX on
"The only way to get rid of a temptation is to give into it." - Oscar Wilde
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
You can't cool something to absolute zero. There's a proof showing that no process can be devised which reduces a system to absolute zero in a finite number of steps. You can get down to a few pico-Kelvins using laser cooling, though. Coolants stop being useful in the tens of Kelvins range, so cryogenic systems operating below that level use mechanical methods like diffusion pumping or magneto-optical trapping.
I think we already established this to a less detailed but equally meaningful degree.
Absolute zero also has nothing to do with gases or state graphs. It's the temperature of a system with minimum entropy. A collection of molecules at absolute zero wouldn't have a volume of zero because the minimum entropy state of the system isn't a singularity.
You are mistaken, and just confusing yourself. We know exactly what temperature 0K is in Celsius or Farenheit. If it's impossible to reach, how do we know it's value? Obviously we couldn't have measured it. If we've never actually achieved minimum entropy, then how could we measure absolute zero to know what temperature it is?
Because, despite your incorrect claim, absolute zero is calculated as the point on a temp/volume graph where volume of gas would equal zero, in some alternate universe where such a thing was possible anywhere but on a graph.
The only reason anyone (including Lord Kelvin and even earlier scientists) ever claimed that 0K = -273.15 Celsius is because if you follow Charles's Law, and if you measure the volume of gas at constant pressure and two different temperatures, and then extrapolate the line all the way to the same pressure and volume 0, you predict a temperature reading of -273.15C. This is where the calculation of absolute zero comes from. Try it. Any plot of temp/volume on a graph (at constant pressure) has an origin at 0K and 0mL. Or, equivalently, you can use a constant volume and extrapolate to a pressure of zero.
As I pointed out, as far as we know, no amount of any element or compound in the universe would remain gaseous as it's volume approached zero, they all go liquid at some point. As you pointed out redundantly, a collection of molecules at absolute zero couldn't really have a volume of zero. This is all parallel to my point. Absolute zero is calculated in a manner that pretty much denies its own possibility. The very notion of it would seem to be impossible.
I'm always confused by your 'observation is reality' stance. There are plenty of things in the universe that we either don't have the technology to directly observe or have reason to believe that such technology can't exist. Are none of them real? We can't send a probe into the center of the sun, so is there just nothing in there?
I'm confused by a lot of things, including how you react to some basic scientific definitions with statements like, "it has nothing to do with that." I'm also confused that you don't see the simple point here - the statement "Absolute zero is the lowest possible temperature" was given as an absolute truth. You yourself have given a couple reasons, including a proof no less, as to why we believe that absolute zero isn't a possible temperature. So which is it? Is it a possible temperature, or is it not? If it is, how so? The very way it is calculated is a known impossibility. You really don't see any issues here that call into question what notion of "truth" is being used? You really have no problem saying that absolute zero is the coldest possible temperature but also saying it is an impossible temperature?
Your analogy of the sun doesn't quite match up, but that would only derail this right now.
Absolute zero also has nothing to do with gases or state graphs. It's the temperature of a system with minimum entropy. A collection of molecules at absolute zero wouldn't have a volume of zero because the minimum entropy state of the system isn't a singularity.
You are mistaken, and just confusing yourself. We know exactly what temperature 0K is in Celsius or Farenheit. If it's impossible to reach, how do we know it's value? Obviously we couldn't have measured it. If we've never actually achieved minimum entropy, then how could we measure absolute zero to know what temperature it is?
Because, despite your incorrect claim, absolute zero is calculated as the point on a temp/volume graph where volume of gas would equal zero, in some alternate universe where such a thing was possible anywhere but on a graph.
The only reason anyone (including Lord Kelvin and even earlier scientists) ever claimed that 0K = -273.15 Celsius is because if you follow Charles's Law, and if you measure the volume of gas at constant pressure and two different temperatures, and then extrapolate the line all the way to the same pressure and volume 0, you predict a temperature reading of -273.15C. This is where the calculation of absolute zero comes from. Try it. Any plot of temp/volume on a graph (at constant pressure) has an origin at 0K and 0mL. Or, equivalently, you can use a constant volume and extrapolate to a pressure of zero.
As I pointed out, as far as we know, no amount of any element or compound in the universe would remain gaseous as it's volume approached zero, they all go liquid at some point. As you pointed out redundantly, a collection of molecules at absolute zero couldn't really have a volume of zero. This is all parallel to my point. Absolute zero is calculated in a manner that pretty much denies its own possibility. The very notion of it would seem to be impossible.
You do realize science has done a lot of things since 1848 right?
Absolute 0 is not a reference to the Ideal Gas law (of which Charle's law is a special case). The ideal gas law doesn't apply to any gas because it's first assumption is that a gas is made up of particles with an infinitely small volume.
Whether or not a scientist in 1848 realized this (of which it was clearly realized that the law wouldn't work at all for very low temperatures) is irrelevant to the fact that absolute zero is a real temperature, though not necessarily one we can ever observe. It's also worth nothing that the modern consideration of absolute zero treats the quantum mechanical noise of any particle as separate to it's thermodynamic temperature - which would be a correct treatment, since the whole point of quantum noise is that it averages out to zero (hence why vacuum energy is not generally viable and matter isn't exploding into existence all around us all the time).
EDIT: To highlight the problem I have with your position - consider this: what is the fastest speed a fermion (i.e. regular, non-force exchange particle matter) can move at? You would say the speed of light. But - the speed of light is not practically achievable for fermionic matter. That's ok you say - it's a limit, the matter can get infinitely close to that speed but never travel at it.
Consequently though, why then, do you have a problem with the notion that 0 Kelvin is the coldest possible temperature for matter (fermionic matter, as again, whether it applies to bosons at all I'm not actually sure of), given that it's clear we can get infinitely close to it without actually reaching it - in much the same way that we treat light speed.
Both are variables observed to within some certain achievable degree of truth, for which a true value can be inferred.
EDIT 2: To be perfectly clear - this is notwithstanding the somewhat more fluid nature of the speed of light. The point is both are reached by the same observational paradigm, but you are insistent one cannot be "possible" despite an obvious trend. Also some fairly horrendous interpretations of gas laws.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
I'm pretty sure that Yar's response will be yes because he refutes the existence of geometric points. Which is part of what I was referring to with my comment about his stance regarding observables and reality. I don't get it because his stance appears to be that reality is our observation of it and that it is not worthwhile (or possibly not even possible?) to even ask questions about reality that transcend our observational capabilities. Which is, I guess, one way around the solopsism problem, but one that seems weird to me.
I don't get it because his stance appears to be that reality is our observation of it and that it is not worthwhile (or possibly not even possible?) to even ask questions about reality that transcend our observational capabilities. Which is, I guess, one way around the solopsism problem, but one that seems weird to me.
Yeah, the bolded text actually corresponds with a view called verificationism, which is a major part of logical positivism, and has been largely discredited. It's a tempting view, one that I've kind of leaned towards in the past, but was nicked by a thousand cuts and slowly bled to death during the 20th century.
Also, elm:
Feral on
every person who doesn't like an acquired taste always seems to think everyone who likes it is faking it. it should be an official fallacy.
EDIT: To highlight the problem I have with your position - consider this: what is the fastest speed a fermion (i.e. regular, non-force exchange particle matter) can move at? You would say the speed of light. But - the speed of light is not practically achievable for fermionic matter. That's ok you say - it's a limit, the matter can get infinitely close to that speed but never travel at it.
Why would he say the speed of light? The fastest possible speed is clearly less than the speed that would be produced by feeding all the energy in the universe into that fermion, which is itself impossible.
I'd say that the fastest possible speed of a fermion is the fastest speed a fermion actually ever had or will have, since going above that is impossible.
Interesting how the discussion has evolved, though I'm disappointed by the obsession with quantum mechanics that is only tangentially related. Science really has nothing to say about the nature of truth, or how much it matters. People aught to read more academic logicians and philosophers which are much more interesting and relevant to the question at hand.
I brought up absolute zero, because it was an easy example to use to illustrate my point (like the speed of light) about "absolute"/"relative" truth. However, my statements about the difference between them were meant as little more than toy-problem variety speculation based on common usage of "relative truth" or "absolute truth". I gave a stab at why one might bother using the word absolute with truth, instead of simply truth, which was MM's question on the topic. I suppose one could interpret what I said to be that "an absolute truth is a tautology or constant", though that's not exactly what I was trying to say, but close enough that I won't argure the point.
The only reason I could think of for using the "absolute" modifier on truth is if you also choose to use "relative" to describe some forms of "less" true statements as well. This caused me to speculate on their normative usage and that's really all I was trying to address, not the concepts' validity or level of interesting-ness, just the way people that use those terms generally use them. I don't care enough to try to do more than offer educated guess rooted in common usage and some reasoning faclities, so I'll let others decide if absolute and relative truth are valid and worthwhile concepts.
From my perspective as a computer scientist I would never seriously use that terminology, unless someone else did and I needed to play along to have a conversation. Boolean logic, upon which computing is based, gives only true or false as constants and the truth value of a given statement can always be derived exactly at some given point in time. Naturally, the truth value of any statement that includes a variable may change anytime the variable changes, and this is the part that confuses people into thinking that there is an actual difference between varieties of truth, when there really is not (true is always true and false is always false, though they both are represented many different ways). In Boolean Logic, there are simply statements that are true or false when examined, never absolute or relative truths.
This is also why I agreed with Feral that the difference between relative and absolute truths is purely semantics, having no real significance.
I had an argument similar to this thread's basic point with a friend. He's basically the King of Spin and I'm a humble disciple of Truth (but yes, truth is mostly relative and blahblahblah).
From that I realised that, yes, you could 'get with the program' and start teaching spin, or lying - ie, how to convince someone of something you don't believe, or do believe for illogical reasons. But you could also try to teach everyone logic and reasoned debate.
Seriously. If this then that, but not this. Teach kids at an early age (and again, and again) how to find "that" but not "this" and why. Make "Logic and Logical Fallacies" a basic subject. Maybe it'll help with the rest of their schooling. Maybe it will even help them sift through the bull in their adult lives. Who knows?
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
Given sufficient energy, you can confine an electron to an arbitrarily small amount of space. This is why you hear people say that the electron is for all intents and purposes a point particle. This might run contrary to what you've learned about the "classical electron radius", but this concept is just that--a classical limit. Electrons don't really have a radius.
You can't, however, compress it to a literal point, because this would require infinite energy.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
Given sufficient energy, you can confine an electron to an arbitrarily small amount of space. This is why you hear people say that the electron is for all intents and purposes a point particle. This might run contrary to what you've learned about the "classical electron radius", but this concept is just that--a classical limit. Electrons don't really have a radius.
You can't, however, compress it to a literal point, because this would require infinite energy.
Basically the reason things like neutron stars and black holes exist is because with sufficient energy most of the quantum limits on things can be crushed out of existence (e.g. degeneracy pressure in atoms, which in chemistry is why we have orbitals and the like, is just an energy term in the end - with sufficient energy electrons will actually become degenerate).
An elementary particle like an electron, not being "made" of any other stuff, means you can push something else ever closer to it, with a consequent rise in the amount of energy trying to repel you away.
EDIT: Just to add more examples to what Moridin said.
EDIT: To highlight the problem I have with your position - consider this: what is the fastest speed a fermion (i.e. regular, non-force exchange particle matter) can move at? You would say the speed of light. But - the speed of light is not practically achievable for fermionic matter. That's ok you say - it's a limit, the matter can get infinitely close to that speed but never travel at it.
Why would he say the speed of light? The fastest possible speed is clearly less than the speed that would be produced by feeding all the energy in the universe into that fermion, which is itself impossible.
I'd say that the fastest possible speed of a fermion is the fastest speed a fermion actually ever had or will have, since going above that is impossible.
How is it that you can know what all speeds that all fermions will ever have? Can you say that at some point one will have the speed just under the limit? Can you say that one wont? How can you know either of those facts?
If we adopt your position, then we run into that kind of problem. Of course, you can't really chop that part off and just use the first half of your statement, because that also has obvious problems.
I think that the only solution is to throw the whole notion away and go with something else.
Also, ELM - I'm so hot right now. Keep talking about physics...yeah...that's it...
LoserForHireX on
"The only way to get rid of a temptation is to give into it." - Oscar Wilde
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
Me too, or nearly always. Because I'm a born liar and if I didn't make a special effort god knows what would happen.
Fun. Fun is what would happen.
The question is, when is it OK to lie? Some people would say "NEVER" while others would not have a problem with the occasional lie. Personally, I don't have a problem with the occasional lie as long as you can justify it and no one gets hurt.
[EDIT: To highlight the problem I have with your position - consider this: what is the fastest speed a fermion (i.e. regular, non-force exchange particle matter) can move at? You would say the speed of light. But - the speed of light is not practically achievable for fermionic matter. That's ok you say - it's a limit, the matter can get infinitely close to that speed but never travel at it.
Consequently though, why then, do you have a problem with the notion that 0 Kelvin is the coldest possible temperature for matter (fermionic matter, as again, whether it applies to bosons at all I'm not actually sure of), given that it's clear we can get infinitely close to it without actually reaching it - in much the same way that we treat light speed.
Both are variables observed to within some certain achievable degree of truth, for which a true value can be inferred.
EDIT 2: To be perfectly clear - this is notwithstanding the somewhat more fluid nature of the speed of light. The point is both are reached by the same observational paradigm, but you are insistent one cannot be "possible" despite an obvious trend. Also some fairly horrendous interpretations of gas laws.
IIRC my very first response to this absolute zero thing was to specify that it was perhaps a well-argued lower bound on possible temperatures. So all the stuff you're saying here doesn't really address any current point of contention.
If I need to be more clear about it to satisfy: I don't have a problem with the practicality of saying "absolute zero is the coldest possible temperature," as a short-hand way of saying that it is a "well-argued lower bound on possible temperatures, but also well-argued as impossible itself." But in a discussion on truth, we ought to acknowledge the contradiction there, and the challenge it raises to an assertion of absolute or objective truth.
Recall that the statement was given as an example of pure, unadulterated absolute truth, in contrast to conditional truths, and in contrast to truths that are simply well-argued practicalities. I am pointing out why I don't accept it as a good example of such a thing, and also explaining some basic science, it seems.
Such as... isn't the speed of light, like, the speed of light? I get that it is also on upper bound on possible speeds of matter, assuming you can't have infinite energy... but don't we also just measure light and say, yup, thar she goes? This is a poor analogy to absolute zero, which has never been measured or observed, only extrapolated. As far as I can tell, you are completely incorrect in your statement that c and 0k are calculated under the same observational paradigm.
As for a "horrendous interpretation of gas laws," I'd prefer a better explanation there. Do you have any evidence of how we calculate absolute zero? You admit we can't/haven't observed it, so obviously we didn't measure it. How do we know its value compared to known thermodynamic measurements? Are you saying that it is calculated by plotting observable temperatures of really cold stuff and then retrofitting a logarithmic equation onto those to find an asymptote? I can't find anything to support that.
But I do see a lot of information you might want to read about how absolute zero is, and has always been, a linear extrapolation of ideal gas laws into territory where we know gasses don't behave ideally (or can even exist, actually). You say that we've done a lot of science since Kelvin's day, but your implication there couldn't be more incorrect. The SI definition of absolute zero is simply "0 kelvin," where the triple-point of water equals 273.16k, and that 273.16 comes from none other than Kelvin and Charles themselves, and where they calculated zero to be based on various measurements of gasses. UC Physics. Hivemind. WP.
Just to be clear: You are 100% incorrect, SI currently defines absolute zero based entirely on the value that Charles and Kelvin extrapolated to be the point at which linear graphs of gas temperatures would go to a pressure or volume of zero. They related it to the triple point of water and Celsius for good measure, but it all still rests entirely on the 273.16 number that Charles and Kelvin gave us.
I would appreciate it if future statements telling me that "it has nothing to do with that" or accusing me of a "horrendous interpretation" would be accompanied by some sort of justification or reference. And there's no need to keep trying to explain to me that zero volume is impossible, or that a lack of entropy is impossible. That is exactly my point. It's defined in terms that we now for a fact to be impossible. You're arguing with yourself. Again, I'm not saying I've proved it false. I'm saying that I reject it as a great example of a perfect truth.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
The Captain is correct. Screw electrons, this is just a Zeno-style paradox in observation, and you could make all sorts of similar hypotheticals to the same end. A center is defined as a point. It's zero-dimensional. How could anything be proven to be precisely at it? The philosophy on this has been sound for decades (or even millenia) before physics caught up. Mathematics, geometry, etc, they are useful tools to model the universe. But they aren't reality. When you neglect to distinguish imaginary conceptual models from scientific data (which can easily happen when so much of physics is math), you are likely to find yourself trapped in riddles.
In other words, you might as well have asked me, "if you always have to cross a midpoint to get from one point to another, then how can you ever cross any distance in a finite number of steps?" Mathematics itself is based on axioms that contain certain inherent paradoxes, so I'm not too concerned that these paradoxes rear their ugly head when you act as if a mathematical concept like a centerpoint is an actual thing that you ought to be able to prove exists somewhere in an electron.
I don't get it because his stance appears to be that reality is our observation of it and that it is not worthwhile (or possibly not even possible?) to even ask questions about reality that transcend our observational capabilities. Which is, I guess, one way around the solopsism problem, but one that seems weird to me.
Yeah, the bolded text actually corresponds with a view called verificationism, which is a major part of logical positivism, and has been largely discredited. It's a tempting view, one that I've kind of leaned towards in the past, but was nicked by a thousand cuts and slowly bled to death during the 20th century.
To me this mostly looks like some more strawmen put into my mouth. To clarify as simply as I can without seriously spiralling this out of control: my point would just be that I have a problem with treating "truth" without any regard for the significance of the conceptual vs. the observed.
The only reason I keep asking about the fact that we've never observed or measured absolute zero is NOT to say, "ah ha, it isn't observed, so it must be false!" I'm bringing it up because Cpt and ELM are very much mistaken about the basic scientific facts concerning where absolute zero comes from, and I'm trying to help them understand why. It isn't a value we ever measured. We used mathematics to model conditions that we know for certain are an impossibility, but used the results of that model anyway, and gave it a name, because we wanted an absolute temperature scale. That's where it comes from. We also have a well-argued theoretical description of it in terms of entropy and energy, which we're also pretty sure is impossible. Good for us. Bad example of objective truth if you ask me.
I have a problem when someone claims to have solved the essence of objective truth because they made something up that doesn't and can't exist, gave it a name, and now call it an objective truth that such is its name. In the end, I don't mind calling the imaginary thing "true" at all, especially if it's a useful concept, a practical approximation that relates to observable things, with general acceptance, and doesn't cause problems. I think that is "truth," more or less. I just don't accept it as proof of, or a solution to, absolute objectivity.
As for a "horrendous interpretation of gas laws," I'd prefer a better explanation there. Do you have any evidence of how we calculate absolute zero? You admit we can't/haven't observed it, so obviously we didn't measure it. How do we know its value compared to known thermodynamic measurements? Are you saying that it is calculated by plotting observable temperatures of really cold stuff and then retrofitting a logarithmic equation onto those to find an asymptote? I can't find anything to support that.
But I do see a lot of information you might want to read about how absolute zero is, and has always been, a linear extrapolation of ideal gas laws into territory where we know gasses don't behave ideally (or can even exist, actually). You say that we've done a lot of science since Kelvin's day, but your implication there couldn't be more incorrect. The SI definition of absolute zero is simply "0 kelvin," where the triple-point of water equals 273.16k, and that 273.16 comes from none other than Kelvin and Charles themselves, and where they calculated zero to be based on various measurements of gasses. UC Physics. Hivemind. WP.
Just to be clear: You are 100% incorrect, SI currently defines absolute zero based entirely on the value that Charles and Kelvin extrapolated to be the point at which linear graphs of gas temperatures would go to a pressure or volume of zero. They related it to the triple point of water and Celsius for good measure, but it all still rests entirely on the 273.16 number that Charles and Kelvin gave us.
I would appreciate it if future statements telling me that "it has nothing to do with that" or accusing me of a "horrendous interpretation" would be accompanied by some sort of justification or reference. And there's no need to keep trying to explain to me that zero volume is impossible, or that a lack of entropy is impossible. That is exactly my point. It's defined in terms that we now for a fact to be impossible. You're arguing with yourself. Again, I'm not saying I've proved it false. I'm saying that I reject it as a great example of a perfect truth.
The triple-point of water is the triple-point of water. Those original values were close to what must be the true values, since we keep measuring them. I don't know why you'd expect them to change dramatically, which seems to be what you're implying - but the original data was known to be wrong because, obviously, the Ideal Gas Law is for a point-gas which doesn't exist.
The SI definition is not fixed to the triple point of water, so much as the magnitude of the unit Kelvin is fixed to the triple point of water, but 0 Kelvin is still defined as - 0 Kelvin, which the triple point of water is defined against. (Wiki Link). The definition is fixed so Celsius and Kelvin will always have a simple linear conversion, but the magnitude of what 0 is is not defined by the triple-point of water.
However, the existence of absolute zero is not a simple extrapolation of ideal gas law and I don't know why you keep hammering on this point because it's wrong. The existence of absolute zero is defined by thermodynamics, which, unlike what you keep saying, is not the Ideal Gas Law.
The definition of thermodynamic temperature shows absolute 0 to be a necessity. If there is a temperature lower then absolute zero, then it would be possible to build a heat engine with greater then 100% efficiency. All sorts of absurd things become possible outside of that bound.
EDIT: It is also worth noting that there's nothing incompatible with this definition and quantum mechanics, since the reason QM is a correct theory - in part - is that the mean of quantum jitter for energy is still zero. It has to be - because again - otherwise it would violate thermodynamics.
Like I said, science has done lots of things since the 1800s - that the founders of thermodynamics got close to the correct answer doesn't mean that's the only thing on which it's based. Much like General Relativity is not just based on the Michelson–Morley experiment even though that was very important foundational research in leading to it.
I do however cede - I think - your point about your original introduction of absolute 0, I came in half-way through a discussion. But your understanding of the interaction of gas laws and thermodynamics is simply incorrect and in some cases fallacious - i.e. the argument that we should think absolute zero is unreachable because any real gas would condense into a liquid.
We all seem to be using the word "true" without any sort of difficulty. What sort of definition are you looking for?
people seem to be talking past each other a fair bit. "what is truth" and "what is true" are both old, annoying philosophical questions, and are kind of inseparable, and they're also prerequisites for the answer the thread title is seeking. i don't think the question is trivial.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
Given sufficient energy, you can confine an electron to an arbitrarily small amount of space. This is why you hear people say that the electron is for all intents and purposes a point particle. This might run contrary to what you've learned about the "classical electron radius", but this concept is just that--a classical limit. Electrons don't really have a radius.
You can't, however, compress it to a literal point, because this would require infinite energy.
Basically the reason things like neutron stars and black holes exist is because with sufficient energy most of the quantum limits on things can be crushed out of existence (e.g. degeneracy pressure in atoms, which in chemistry is why we have orbitals and the like, is just an energy term in the end - with sufficient energy electrons will actually become degenerate).
An elementary particle like an electron, not being "made" of any other stuff, means you can push something else ever closer to it, with a consequent rise in the amount of energy trying to repel you away.
EDIT: Just to add more examples to what Moridin said.
This is a bit off topic, so sorry, and again my physics is a good 7 or 8 years behind me, but I only really ever remember electrons being defined as either orbitals (I'd assume derived from wave function) or a point particle? In other words the idea of an electron as something other than a point in space with a charge (though something of a "fuzzy" point due to uncertainty) or a shape representing a probability field is foreign to me. I understand the concept of an exclusion - ie that only 1 electron in an atom can be in a given energy level or whatever in an atom, but that doesn't seem to be exactly what you're saying.
Also it would seem like to some extent it must be possible for things to impact the 'center' of electrons, otherwise things like electron-positron annihilations or electron particle accelerators wouldn't be possible.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
Given sufficient energy, you can confine an electron to an arbitrarily small amount of space. This is why you hear people say that the electron is for all intents and purposes a point particle. This might run contrary to what you've learned about the "classical electron radius", but this concept is just that--a classical limit. Electrons don't really have a radius.
You can't, however, compress it to a literal point, because this would require infinite energy.
Basically the reason things like neutron stars and black holes exist is because with sufficient energy most of the quantum limits on things can be crushed out of existence (e.g. degeneracy pressure in atoms, which in chemistry is why we have orbitals and the like, is just an energy term in the end - with sufficient energy electrons will actually become degenerate).
An elementary particle like an electron, not being "made" of any other stuff, means you can push something else ever closer to it, with a consequent rise in the amount of energy trying to repel you away.
EDIT: Just to add more examples to what Moridin said.
This is a bit off topic, so sorry, and again my physics is a good 7 or 8 years behind me, but I only really ever remember electrons being defined as either orbitals (I'd assume derived from wave function) or a point particle? In other words the idea of an electron as something other than a point in space with a charge (though something of a "fuzzy" point due to uncertainty) or a shape representing a probability field is foreign to me. I understand the concept of an exclusion - ie that only 1 electron in an atom can be in a given energy level or whatever in an atom, but that doesn't seem to be exactly what you're saying.
Also it would seem like to some extent it must be possible for things to impact the 'center' of electrons, otherwise things like electron-positron annihilations or electron particle accelerators wouldn't be possible.
I'm not really familiar with how the mathematics work out for electron-positron annihilation, but that is a reasonable circumstance under which something could reach the center of an electron - I'm not really sure what happens there.
With regards to electron accelerators though, it doesn't seem incongruous, though it's probably incorrect for me to think, that the main advantage is that the "collisions" concentrate more kinetic energy into smaller spaces, and create a situation where the fastest way to get rid of it is to pop some more particles into existence (the notion of super-stars which explode because their cores get so dense the photons start turning into particle-antiparticle pairs spontaneously would seem to be the same process).
Again, I don't fully understand the physics behind those sorts of interactions beyond a very general concept.
In the case of annihilations, it does occur to me that two charged particles with infinitely small centers would effectively be accelerating towards each other exponentially faster and thus representing a moving electric and thus magnetic field (which would lead to the creation of photons) - but that's probably too classical.
We all seem to be using the word "true" without any sort of difficulty. What sort of definition are you looking for?
people seem to be talking past each other a fair bit. "what is truth" and "what is true" are both old, annoying philosophical questions, and are kind of inseparable, and they're also prerequisites for the answer the thread title is seeking. i don't think the question is trivial.
I'm not sure what's going on with the physics discussion, largely because it seems to be above my scientific pay grade.
However, I think that there is a fundamentally simple problem here that people are really blowing out of proportion.
Again, though, what sort of definition are you looking for? I mean, we seem to all know what it means for something to be true. Now the question such as "what is true?" isn't actually asking simply for a definition, but rather some examples of things that are true. Examples no one could give if there was confusion over what it meant for something to be true.
Now, we do attach all sort of adjectives to true (some of which have reared their ugly heads in this discussion) such as "objective" "absolute" "conditionally" "a priori" "a posteriori" but we all seem to grasp what the word "true" means well enough to understand how it works with all of these modifiers.
So I ask again, what sort of definition are you looking for? Is it something like "a statement is true iff it corresponds to something correct"? Even that seems really to be a tautology since "true" and "correct" seem to be used the same way here. Maybe "a statement is true iff it correctly states a fact about the world" but that doesn't seem to cover all the things that are true. Because we could make statements about another world that might be contradictory to ours in some ways yet still make true statements.
Essentially, I don't know what to tell you other than "something is true if it's true." But I'm sure that you would find that extremely barren.
I'd like to answer your question, but I'm afraid I don't really know what you're looking for.
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"The only way to get rid of a temptation is to give into it." - Oscar Wilde
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
"The only way to get rid of a temptation is to give into it." - Oscar Wilde
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
I prefer the definition "A statement is true if a reasonable person (assumed to be you, the person reading this definition), upon examining it, would conclude that it is true".
Can anyone come up with a counterexample?
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MrMisterJesus dying on the cross in pain? Morally better than us. One has to go "all in".Registered Userregular
The Captain is correct. Screw electrons, this is just a Zeno-style paradox in observation, and you could make all sorts of similar hypotheticals to the same end. A center is defined as a point. It's zero-dimensional. How could anything be proven to be precisely at it? The philosophy on this has been sound for decades (or even millenia) before physics caught up. Mathematics, geometry, etc, they are useful tools to model the universe. But they aren't reality. When you neglect to distinguish imaginary conceptual models from scientific data (which can easily happen when so much of physics is math), you are likely to find yourself trapped in riddles.
In other words, you might as well have asked me, "if you always have to cross a midpoint to get from one point to another, then how can you ever cross any distance in a finite number of steps?" Mathematics itself is based on axioms that contain certain inherent paradoxes, so I'm not too concerned that these paradoxes rear their ugly head when you act as if a mathematical concept like a centerpoint is an actual thing that you ought to be able to prove exists somewhere in an electron.
I'm not sure exactly what you take Zeno's paradoxes to prove. After all, the original goal of the paradoxes was to prove that movement was an illusion and the knowledge of the senses was a lie, so, presumably, that's not what you're going for.
As per the inherent paradoxes in the axioms of mathematics, I'd be surprised if more than one or two people on the board even knew the axioms of ZFC*, and I'd eat my hat if you could derive a contradiction from them, let alone explain how said contradiction could be relevant to modern physics.
(*I'm not being a poser, I definitely only have a sub-basement level knowledge of set theory).
I prefer the definition "A statement is true if a reasonable person (assumed to be you, the person reading this definition), upon examining it, would conclude that it is true".
Can anyone come up with a counterexample?
Even ignoring the immediate circularity of defining truth in terms of what one would conclude is true under idealized circumstances, the more important problem is that the definition is just obviously wrong. There is nothing impossible about a reasonable person examining the evidence and yet rendering the wrong verdict. After all, maybe the evidence was misleading.
For instance, I have every reason to believe that I am not about to die of a stroke (young, healthy, etc. etc.). A reasonable person most certainly would conclude that I am not about to die of a stroke. But that does not mean that it's true that I'm not about to die from a stroke.
On the one hand, what a reasonable person would conclude about my current cerebral health depends on facts about that person, their psychology, and their immediately available evidence. On the other hand, what is actually true of my current cerebral health depends on facts about the current state of my brain. These are just different categories, and there's no reason to think that they always line up, let alone that the very meaning of the word 'true' guarantees that they must always line up.
The Captain is correct. Screw electrons, this is just a Zeno-style paradox in observation, and you could make all sorts of similar hypotheticals to the same end. A center is defined as a point. It's zero-dimensional. How could anything be proven to be precisely at it? The philosophy on this has been sound for decades (or even millenia) before physics caught up. Mathematics, geometry, etc, they are useful tools to model the universe. But they aren't reality. When you neglect to distinguish imaginary conceptual models from scientific data (which can easily happen when so much of physics is math), you are likely to find yourself trapped in riddles.
In other words, you might as well have asked me, "if you always have to cross a midpoint to get from one point to another, then how can you ever cross any distance in a finite number of steps?" Mathematics itself is based on axioms that contain certain inherent paradoxes, so I'm not too concerned that these paradoxes rear their ugly head when you act as if a mathematical concept like a centerpoint is an actual thing that you ought to be able to prove exists somewhere in an electron.
I'm not sure exactly what you take Zeno's paradoxes to prove. After all, the original goal of the paradoxes was to prove that movement was an illusion and the knowledge of the senses was a lie, so, presumably, that's not what you're going for.
As per the inherent paradoxes in the axioms of mathematics, I'd be surprised if more than one or two people on the board even knew the axioms of ZFC*, and I'd eat my hat if you could derive a contradiction from them, let alone explain how said contradiction could be relevant to modern physics.
(*I'm not being a poser, I definitely only have a sub-basement level knowledge of set theory).
As far as I know, in the modern interpretation, Zeno's Paradox disappears with the introduction of the idea of a converging series. Mathematicians do not see Zeno's Paradox as some kind of indication that the axioms of math are divorced from reality.
You'd have to look at the 'C' of ZFC set theory for that. The axiom of Choice has all kinds of fun implications, the Banach-Tarski Paradox for instance--the result that it's possible to cut a sphere into finitely many pieces, and rearrange those pieces to form two whole spheres.
And considering how seemingly mundane the axiom of choice is, I consider that result far more profound and puzzling than some argument involving turtles and halving distances repeatedly.
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MrMisterJesus dying on the cross in pain? Morally better than us. One has to go "all in".Registered Userregular
edited June 2011
I was under the impression that Banach-Tarski was less of a contradiction than it was an unexpected result. If it were a contradiction, then ZFC would imply all propositions and have to go the way of naive set theory. Instead, it's like the fact that infinite sets can be paired 1-1 with their proper subsets: a super-weird fact.
We all seem to be using the word "true" without any sort of difficulty. What sort of definition are you looking for?
people seem to be talking past each other a fair bit. "what is truth" and "what is true" are both old, annoying philosophical questions, and are kind of inseparable, and they're also prerequisites for the answer the thread title is seeking. i don't think the question is trivial.
I'm not sure what's going on with the physics discussion, largely because it seems to be above my scientific pay grade.
However, I think that there is a fundamentally simple problem here that people are really blowing out of proportion.
Again, though, what sort of definition are you looking for? I mean, we seem to all know what it means for something to be true. Now the question such as "what is true?" isn't actually asking simply for a definition, but rather some examples of things that are true. Examples no one could give if there was confusion over what it meant for something to be true.
Now, we do attach all sort of adjectives to true (some of which have reared their ugly heads in this discussion) such as "objective" "absolute" "conditionally" "a priori" "a posteriori" but we all seem to grasp what the word "true" means well enough to understand how it works with all of these modifiers.
So I ask again, what sort of definition are you looking for? Is it something like "a statement is true iff it corresponds to something correct"? Even that seems really to be a tautology since "true" and "correct" seem to be used the same way here. Maybe "a statement is true iff it correctly states a fact about the world" but that doesn't seem to cover all the things that are true. Because we could make statements about another world that might be contradictory to ours in some ways yet still make true statements.
Essentially, I don't know what to tell you other than "something is true if it's true." But I'm sure that you would find that extremely barren.
I'd like to answer your question, but I'm afraid I don't really know what you're looking for.
I think that Evil is being quite reasonable. I mean there's many flavours and varieties of the correspondence theory of truth - some basic, some not so much. There are multiple manifestations of the coherence theory of truth. Pragmatic theories invoke related, but quite different theories of truth. And these are just the big-ticket items. If you try and say what it means for something to be "true" you explore and define the content of the concept you are working with. Different intelligent people have constructed theories of truth that reveal them to be using the word differently - showing differences between the content of the concepts they all name "truth" and showing that these differences are related to differences in many other fundamental concepts such as "mind", "matter", "intention", "external", "internal", "reality", and so on. And virtually all theories of truth proposed in philosophy (with the exception of a few outliers) have the benefit of accomodating most of the common use of the vague and loosely defined term "truth" that we use in daily conversation, and is perfectly good for our usual purposes. Where philosophy goes bad and becomes a waste of time (and this is what I think that Evil wanted to make sure didn't happen) is when people try to import common concepts into philosophical discussion that requries precise and well-defined concepts without making clear exactly how they are using the term.
Right, right, it isn't a contradiction within ZFC set theory. It's just a result of the Axiom of Choice.
But have you ever seen someone cut up an orange into two complete oranges? :P
Well, the Banach-Tarski cutting method is, itself, inherently non-physical, so I don't think you could really turn it into a problem for physics. It's only a problem for mathematicians if you don't like that result.
But mathematics is only based on the axioms of set theory in the same way that medicine is based on germ theory. Having it makes advanced applications possible and it's a much better description of what's going on than we previously had, but not knowing set theory didn't stop people doing math for millenia before it was invented. So most set theories seem to be based on some mathematicians not liking something about a previously existing one rather than actualy problems with it. It's not exactly a problem for anyone besides a certain portion of the mathematics community that ZFC doesn't allow for a universal set, for example.
Anyway, back to the topic...
It seems to me that saying that all truths are truths and that calling some relative and some absolute is semantics ignores a lot of things about the person making the statement. As MrMister pointed out, many "true" statements are based on imperfect knowledge, which in most non-trivial cases is going to be what people have. Beyond that are value and ethical statements, where the back-load going into the truth to make it absolute is just enormous and not really communicable by any means. It is arguably an absolute truth that "Ice cream is delicious" because I think it is when I say it, but there is no method to communicate the information required to qualify it into a statement which any reader at any time or place in the universe would agree is true.
I don't know where the dividing line is, but it seems like there must be a division between statements which are true for any observer provided a finite, communicable amount of qualifying data and statements which are not.
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MrMisterJesus dying on the cross in pain? Morally better than us. One has to go "all in".Registered Userregular
As MrMister pointed out, many "true" statements are based on imperfect knowledge, which in most non-trivial cases is going to be what people have. Beyond that are value and ethical statements, where the back-load going into the truth to make it absolute is just enormous and not really communicable by any means. It is arguably an absolute truth that "Ice cream is delicious" because I think it is when I say it, but there is no method to communicate the information required to qualify it into a statement which any reader at any time or place in the universe would agree is true.
Statements of taste ('he's beautiful,' 'fish sticks are tasty'), epistemic modals ('possibly in the drawer,' 'might not rain,' 'probably arriving on time,'), and ethical claims ('murder is wrong,' 'one ought to donate') are all domains of discourse which people attempt to give relativist glosses; I just finished a class where we read some of the recent work by people like MacFarlane and Richard claiming that we need relative truth to make sense of the conversational data on the way that people offer and retract those sorts of claims. Of those, ethics is probably the most traditional area where people attempt relativist theories, and epistemic modals are the most recent trendy one.
Which is why I was sort of surprised by the earlier equation of relative truth with omitted information. Generally, philosophers don't want to relativize truth if they don't have to, and you most certainly don't have to in order to deal with omitted information. The areas where it looks like you might have to after all are not those dealing with omitted information, but rather those dealing with taste, epistemic modals, and ethics.
Edit: for the record, I'm not surprised that no one immediately mentioned relatively rarefied topics like epistemic modals, I'm more surprised that no one went for ethics off the bat.
For instance, I have every reason to believe that I am not about to die of a stroke (young, healthy, etc. etc.). A reasonable person most certainly would conclude that I am not about to die of a stroke. But that does not mean that it's true that I'm not about to die from a stroke.
But you just concluded that it isn't necessarily true, so why are you claiming that it makes sense to conclude that it's true?
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Has anyone defined what it means to be "defined"?
Absolute zero also has nothing to do with gases or state graphs. It's the temperature of a system with minimum entropy. A collection of molecules at absolute zero wouldn't have a volume of zero because the minimum entropy state of the system isn't a singularity.
I'm always confused by your 'observation is reality' stance. There are plenty of things in the universe that we either don't have the technology to directly observe or have reason to believe that such technology can't exist. Are none of them real? We can't send a probe into the center of the sun, so is there just nothing in there?
What does authentic mean here?
By-golly, gee-wizz, that is a damn good point you have there, sir.
I guess I mean it as a synonym for original, what existed at first or what is attached and descended from that which existed originally.
Is there some confusion?
We all seem to be using the word "true" without any sort of difficulty. What sort of definition are you looking for?
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
Hagen-das?
He has what is arguably the most excellent point in all of philosophy.
You are mistaken, and just confusing yourself. We know exactly what temperature 0K is in Celsius or Farenheit. If it's impossible to reach, how do we know it's value? Obviously we couldn't have measured it. If we've never actually achieved minimum entropy, then how could we measure absolute zero to know what temperature it is?
Because, despite your incorrect claim, absolute zero is calculated as the point on a temp/volume graph where volume of gas would equal zero, in some alternate universe where such a thing was possible anywhere but on a graph.
The only reason anyone (including Lord Kelvin and even earlier scientists) ever claimed that 0K = -273.15 Celsius is because if you follow Charles's Law, and if you measure the volume of gas at constant pressure and two different temperatures, and then extrapolate the line all the way to the same pressure and volume 0, you predict a temperature reading of -273.15C. This is where the calculation of absolute zero comes from. Try it. Any plot of temp/volume on a graph (at constant pressure) has an origin at 0K and 0mL. Or, equivalently, you can use a constant volume and extrapolate to a pressure of zero.
As I pointed out, as far as we know, no amount of any element or compound in the universe would remain gaseous as it's volume approached zero, they all go liquid at some point. As you pointed out redundantly, a collection of molecules at absolute zero couldn't really have a volume of zero. This is all parallel to my point. Absolute zero is calculated in a manner that pretty much denies its own possibility. The very notion of it would seem to be impossible.
I'm confused by a lot of things, including how you react to some basic scientific definitions with statements like, "it has nothing to do with that." I'm also confused that you don't see the simple point here - the statement "Absolute zero is the lowest possible temperature" was given as an absolute truth. You yourself have given a couple reasons, including a proof no less, as to why we believe that absolute zero isn't a possible temperature. So which is it? Is it a possible temperature, or is it not? If it is, how so? The very way it is calculated is a known impossibility. You really don't see any issues here that call into question what notion of "truth" is being used? You really have no problem saying that absolute zero is the coldest possible temperature but also saying it is an impossible temperature?
Your analogy of the sun doesn't quite match up, but that would only derail this right now.
I like your definition! If you can use information without difficulty, then that information is true. Impressive.
You do realize science has done a lot of things since 1848 right?
Absolute 0 is not a reference to the Ideal Gas law (of which Charle's law is a special case). The ideal gas law doesn't apply to any gas because it's first assumption is that a gas is made up of particles with an infinitely small volume.
Whether or not a scientist in 1848 realized this (of which it was clearly realized that the law wouldn't work at all for very low temperatures) is irrelevant to the fact that absolute zero is a real temperature, though not necessarily one we can ever observe. It's also worth nothing that the modern consideration of absolute zero treats the quantum mechanical noise of any particle as separate to it's thermodynamic temperature - which would be a correct treatment, since the whole point of quantum noise is that it averages out to zero (hence why vacuum energy is not generally viable and matter isn't exploding into existence all around us all the time).
EDIT: To highlight the problem I have with your position - consider this: what is the fastest speed a fermion (i.e. regular, non-force exchange particle matter) can move at? You would say the speed of light. But - the speed of light is not practically achievable for fermionic matter. That's ok you say - it's a limit, the matter can get infinitely close to that speed but never travel at it.
Consequently though, why then, do you have a problem with the notion that 0 Kelvin is the coldest possible temperature for matter (fermionic matter, as again, whether it applies to bosons at all I'm not actually sure of), given that it's clear we can get infinitely close to it without actually reaching it - in much the same way that we treat light speed.
Both are variables observed to within some certain achievable degree of truth, for which a true value can be inferred.
EDIT 2: To be perfectly clear - this is notwithstanding the somewhat more fluid nature of the speed of light. The point is both are reached by the same observational paradigm, but you are insistent one cannot be "possible" despite an obvious trend. Also some fairly horrendous interpretations of gas laws.
EDIT 3: Somewhat better example - is the center of an electron a real place? An electron is an unbounded sphere of charge of a value no greater then e. You can get infinitely close to the center of an electron, but there's no way to actually be at the center of an electron. Would you be happy to claim that the center of an electron is not in fact a real location?
I'm pretty sure that Yar's response will be yes because he refutes the existence of geometric points. Which is part of what I was referring to with my comment about his stance regarding observables and reality. I don't get it because his stance appears to be that reality is our observation of it and that it is not worthwhile (or possibly not even possible?) to even ask questions about reality that transcend our observational capabilities. Which is, I guess, one way around the solopsism problem, but one that seems weird to me.
Yeah, the bolded text actually corresponds with a view called verificationism, which is a major part of logical positivism, and has been largely discredited. It's a tempting view, one that I've kind of leaned towards in the past, but was nicked by a thousand cuts and slowly bled to death during the 20th century.
Also, elm:
the "no true scotch man" fallacy.
Why would he say the speed of light? The fastest possible speed is clearly less than the speed that would be produced by feeding all the energy in the universe into that fermion, which is itself impossible.
I'd say that the fastest possible speed of a fermion is the fastest speed a fermion actually ever had or will have, since going above that is impossible.
I brought up absolute zero, because it was an easy example to use to illustrate my point (like the speed of light) about "absolute"/"relative" truth. However, my statements about the difference between them were meant as little more than toy-problem variety speculation based on common usage of "relative truth" or "absolute truth". I gave a stab at why one might bother using the word absolute with truth, instead of simply truth, which was MM's question on the topic. I suppose one could interpret what I said to be that "an absolute truth is a tautology or constant", though that's not exactly what I was trying to say, but close enough that I won't argure the point.
The only reason I could think of for using the "absolute" modifier on truth is if you also choose to use "relative" to describe some forms of "less" true statements as well. This caused me to speculate on their normative usage and that's really all I was trying to address, not the concepts' validity or level of interesting-ness, just the way people that use those terms generally use them. I don't care enough to try to do more than offer educated guess rooted in common usage and some reasoning faclities, so I'll let others decide if absolute and relative truth are valid and worthwhile concepts.
From my perspective as a computer scientist I would never seriously use that terminology, unless someone else did and I needed to play along to have a conversation. Boolean logic, upon which computing is based, gives only true or false as constants and the truth value of a given statement can always be derived exactly at some given point in time. Naturally, the truth value of any statement that includes a variable may change anytime the variable changes, and this is the part that confuses people into thinking that there is an actual difference between varieties of truth, when there really is not (true is always true and false is always false, though they both are represented many different ways). In Boolean Logic, there are simply statements that are true or false when examined, never absolute or relative truths.
This is also why I agreed with Feral that the difference between relative and absolute truths is purely semantics, having no real significance.
From that I realised that, yes, you could 'get with the program' and start teaching spin, or lying - ie, how to convince someone of something you don't believe, or do believe for illogical reasons. But you could also try to teach everyone logic and reasoned debate.
Seriously. If this then that, but not this. Teach kids at an early age (and again, and again) how to find "that" but not "this" and why. Make "Logic and Logical Fallacies" a basic subject. Maybe it'll help with the rest of their schooling. Maybe it will even help them sift through the bull in their adult lives. Who knows?
hAmmONd IsnT A mAin TAnk
Can you elaborate a bit? Not a physicist but based on my limited knowledge of college QM that whole question makes no sense at all.
Given sufficient energy, you can confine an electron to an arbitrarily small amount of space. This is why you hear people say that the electron is for all intents and purposes a point particle. This might run contrary to what you've learned about the "classical electron radius", but this concept is just that--a classical limit. Electrons don't really have a radius.
You can't, however, compress it to a literal point, because this would require infinite energy.
Basically the reason things like neutron stars and black holes exist is because with sufficient energy most of the quantum limits on things can be crushed out of existence (e.g. degeneracy pressure in atoms, which in chemistry is why we have orbitals and the like, is just an energy term in the end - with sufficient energy electrons will actually become degenerate).
An elementary particle like an electron, not being "made" of any other stuff, means you can push something else ever closer to it, with a consequent rise in the amount of energy trying to repel you away.
EDIT: Just to add more examples to what Moridin said.
How is it that you can know what all speeds that all fermions will ever have? Can you say that at some point one will have the speed just under the limit? Can you say that one wont? How can you know either of those facts?
If we adopt your position, then we run into that kind of problem. Of course, you can't really chop that part off and just use the first half of your statement, because that also has obvious problems.
I think that the only solution is to throw the whole notion away and go with something else.
Also, ELM - I'm so hot right now. Keep talking about physics...yeah...that's it...
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
It makes my life difficult.
Me too, or nearly always. Because I'm a born liar and if I didn't make a special effort god knows what would happen.
Fun. Fun is what would happen.
The question is, when is it OK to lie? Some people would say "NEVER" while others would not have a problem with the occasional lie. Personally, I don't have a problem with the occasional lie as long as you can justify it and no one gets hurt.
If I need to be more clear about it to satisfy: I don't have a problem with the practicality of saying "absolute zero is the coldest possible temperature," as a short-hand way of saying that it is a "well-argued lower bound on possible temperatures, but also well-argued as impossible itself." But in a discussion on truth, we ought to acknowledge the contradiction there, and the challenge it raises to an assertion of absolute or objective truth.
Recall that the statement was given as an example of pure, unadulterated absolute truth, in contrast to conditional truths, and in contrast to truths that are simply well-argued practicalities. I am pointing out why I don't accept it as a good example of such a thing, and also explaining some basic science, it seems.
Such as... isn't the speed of light, like, the speed of light? I get that it is also on upper bound on possible speeds of matter, assuming you can't have infinite energy... but don't we also just measure light and say, yup, thar she goes? This is a poor analogy to absolute zero, which has never been measured or observed, only extrapolated. As far as I can tell, you are completely incorrect in your statement that c and 0k are calculated under the same observational paradigm.
As for a "horrendous interpretation of gas laws," I'd prefer a better explanation there. Do you have any evidence of how we calculate absolute zero? You admit we can't/haven't observed it, so obviously we didn't measure it. How do we know its value compared to known thermodynamic measurements? Are you saying that it is calculated by plotting observable temperatures of really cold stuff and then retrofitting a logarithmic equation onto those to find an asymptote? I can't find anything to support that.
But I do see a lot of information you might want to read about how absolute zero is, and has always been, a linear extrapolation of ideal gas laws into territory where we know gasses don't behave ideally (or can even exist, actually). You say that we've done a lot of science since Kelvin's day, but your implication there couldn't be more incorrect. The SI definition of absolute zero is simply "0 kelvin," where the triple-point of water equals 273.16k, and that 273.16 comes from none other than Kelvin and Charles themselves, and where they calculated zero to be based on various measurements of gasses. UC Physics. Hivemind. WP.
Just to be clear: You are 100% incorrect, SI currently defines absolute zero based entirely on the value that Charles and Kelvin extrapolated to be the point at which linear graphs of gas temperatures would go to a pressure or volume of zero. They related it to the triple point of water and Celsius for good measure, but it all still rests entirely on the 273.16 number that Charles and Kelvin gave us.
I would appreciate it if future statements telling me that "it has nothing to do with that" or accusing me of a "horrendous interpretation" would be accompanied by some sort of justification or reference. And there's no need to keep trying to explain to me that zero volume is impossible, or that a lack of entropy is impossible. That is exactly my point. It's defined in terms that we now for a fact to be impossible. You're arguing with yourself. Again, I'm not saying I've proved it false. I'm saying that I reject it as a great example of a perfect truth.
The Captain is correct. Screw electrons, this is just a Zeno-style paradox in observation, and you could make all sorts of similar hypotheticals to the same end. A center is defined as a point. It's zero-dimensional. How could anything be proven to be precisely at it? The philosophy on this has been sound for decades (or even millenia) before physics caught up. Mathematics, geometry, etc, they are useful tools to model the universe. But they aren't reality. When you neglect to distinguish imaginary conceptual models from scientific data (which can easily happen when so much of physics is math), you are likely to find yourself trapped in riddles.
In other words, you might as well have asked me, "if you always have to cross a midpoint to get from one point to another, then how can you ever cross any distance in a finite number of steps?" Mathematics itself is based on axioms that contain certain inherent paradoxes, so I'm not too concerned that these paradoxes rear their ugly head when you act as if a mathematical concept like a centerpoint is an actual thing that you ought to be able to prove exists somewhere in an electron.
To me this mostly looks like some more strawmen put into my mouth. To clarify as simply as I can without seriously spiralling this out of control: my point would just be that I have a problem with treating "truth" without any regard for the significance of the conceptual vs. the observed.
The only reason I keep asking about the fact that we've never observed or measured absolute zero is NOT to say, "ah ha, it isn't observed, so it must be false!" I'm bringing it up because Cpt and ELM are very much mistaken about the basic scientific facts concerning where absolute zero comes from, and I'm trying to help them understand why. It isn't a value we ever measured. We used mathematics to model conditions that we know for certain are an impossibility, but used the results of that model anyway, and gave it a name, because we wanted an absolute temperature scale. That's where it comes from. We also have a well-argued theoretical description of it in terms of entropy and energy, which we're also pretty sure is impossible. Good for us. Bad example of objective truth if you ask me.
I have a problem when someone claims to have solved the essence of objective truth because they made something up that doesn't and can't exist, gave it a name, and now call it an objective truth that such is its name. In the end, I don't mind calling the imaginary thing "true" at all, especially if it's a useful concept, a practical approximation that relates to observable things, with general acceptance, and doesn't cause problems. I think that is "truth," more or less. I just don't accept it as proof of, or a solution to, absolute objectivity.
The triple-point of water is the triple-point of water. Those original values were close to what must be the true values, since we keep measuring them. I don't know why you'd expect them to change dramatically, which seems to be what you're implying - but the original data was known to be wrong because, obviously, the Ideal Gas Law is for a point-gas which doesn't exist.
The SI definition is not fixed to the triple point of water, so much as the magnitude of the unit Kelvin is fixed to the triple point of water, but 0 Kelvin is still defined as - 0 Kelvin, which the triple point of water is defined against. (Wiki Link). The definition is fixed so Celsius and Kelvin will always have a simple linear conversion, but the magnitude of what 0 is is not defined by the triple-point of water.
However, the existence of absolute zero is not a simple extrapolation of ideal gas law and I don't know why you keep hammering on this point because it's wrong. The existence of absolute zero is defined by thermodynamics, which, unlike what you keep saying, is not the Ideal Gas Law.
The definition of thermodynamic temperature shows absolute 0 to be a necessity. If there is a temperature lower then absolute zero, then it would be possible to build a heat engine with greater then 100% efficiency. All sorts of absurd things become possible outside of that bound.
EDIT: It is also worth noting that there's nothing incompatible with this definition and quantum mechanics, since the reason QM is a correct theory - in part - is that the mean of quantum jitter for energy is still zero. It has to be - because again - otherwise it would violate thermodynamics.
Like I said, science has done lots of things since the 1800s - that the founders of thermodynamics got close to the correct answer doesn't mean that's the only thing on which it's based. Much like General Relativity is not just based on the Michelson–Morley experiment even though that was very important foundational research in leading to it.
I do however cede - I think - your point about your original introduction of absolute 0, I came in half-way through a discussion. But your understanding of the interaction of gas laws and thermodynamics is simply incorrect and in some cases fallacious - i.e. the argument that we should think absolute zero is unreachable because any real gas would condense into a liquid.
people seem to be talking past each other a fair bit. "what is truth" and "what is true" are both old, annoying philosophical questions, and are kind of inseparable, and they're also prerequisites for the answer the thread title is seeking. i don't think the question is trivial.
This is a bit off topic, so sorry, and again my physics is a good 7 or 8 years behind me, but I only really ever remember electrons being defined as either orbitals (I'd assume derived from wave function) or a point particle? In other words the idea of an electron as something other than a point in space with a charge (though something of a "fuzzy" point due to uncertainty) or a shape representing a probability field is foreign to me. I understand the concept of an exclusion - ie that only 1 electron in an atom can be in a given energy level or whatever in an atom, but that doesn't seem to be exactly what you're saying.
Also it would seem like to some extent it must be possible for things to impact the 'center' of electrons, otherwise things like electron-positron annihilations or electron particle accelerators wouldn't be possible.
I'm not really familiar with how the mathematics work out for electron-positron annihilation, but that is a reasonable circumstance under which something could reach the center of an electron - I'm not really sure what happens there.
With regards to electron accelerators though, it doesn't seem incongruous, though it's probably incorrect for me to think, that the main advantage is that the "collisions" concentrate more kinetic energy into smaller spaces, and create a situation where the fastest way to get rid of it is to pop some more particles into existence (the notion of super-stars which explode because their cores get so dense the photons start turning into particle-antiparticle pairs spontaneously would seem to be the same process).
Again, I don't fully understand the physics behind those sorts of interactions beyond a very general concept.
In the case of annihilations, it does occur to me that two charged particles with infinitely small centers would effectively be accelerating towards each other exponentially faster and thus representing a moving electric and thus magnetic field (which would lead to the creation of photons) - but that's probably too classical.
I'm not sure what's going on with the physics discussion, largely because it seems to be above my scientific pay grade.
However, I think that there is a fundamentally simple problem here that people are really blowing out of proportion.
Again, though, what sort of definition are you looking for? I mean, we seem to all know what it means for something to be true. Now the question such as "what is true?" isn't actually asking simply for a definition, but rather some examples of things that are true. Examples no one could give if there was confusion over what it meant for something to be true.
Now, we do attach all sort of adjectives to true (some of which have reared their ugly heads in this discussion) such as "objective" "absolute" "conditionally" "a priori" "a posteriori" but we all seem to grasp what the word "true" means well enough to understand how it works with all of these modifiers.
So I ask again, what sort of definition are you looking for? Is it something like "a statement is true iff it corresponds to something correct"? Even that seems really to be a tautology since "true" and "correct" seem to be used the same way here. Maybe "a statement is true iff it correctly states a fact about the world" but that doesn't seem to cover all the things that are true. Because we could make statements about another world that might be contradictory to ours in some ways yet still make true statements.
Essentially, I don't know what to tell you other than "something is true if it's true." But I'm sure that you would find that extremely barren.
I'd like to answer your question, but I'm afraid I don't really know what you're looking for.
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
Preposterous Knave!!!
Luminiferous Ether and Phlogiston for all!!!!
"We believe in the people and their 'wisdom' as if there was some special secret entrance to knowledge that barred to anyone who had ever learned anything." - Friedrich Nietzsche
Can anyone come up with a counterexample?
I'm not sure exactly what you take Zeno's paradoxes to prove. After all, the original goal of the paradoxes was to prove that movement was an illusion and the knowledge of the senses was a lie, so, presumably, that's not what you're going for.
As per the inherent paradoxes in the axioms of mathematics, I'd be surprised if more than one or two people on the board even knew the axioms of ZFC*, and I'd eat my hat if you could derive a contradiction from them, let alone explain how said contradiction could be relevant to modern physics.
(*I'm not being a poser, I definitely only have a sub-basement level knowledge of set theory).
Even ignoring the immediate circularity of defining truth in terms of what one would conclude is true under idealized circumstances, the more important problem is that the definition is just obviously wrong. There is nothing impossible about a reasonable person examining the evidence and yet rendering the wrong verdict. After all, maybe the evidence was misleading.
For instance, I have every reason to believe that I am not about to die of a stroke (young, healthy, etc. etc.). A reasonable person most certainly would conclude that I am not about to die of a stroke. But that does not mean that it's true that I'm not about to die from a stroke.
On the one hand, what a reasonable person would conclude about my current cerebral health depends on facts about that person, their psychology, and their immediately available evidence. On the other hand, what is actually true of my current cerebral health depends on facts about the current state of my brain. These are just different categories, and there's no reason to think that they always line up, let alone that the very meaning of the word 'true' guarantees that they must always line up.
As far as I know, in the modern interpretation, Zeno's Paradox disappears with the introduction of the idea of a converging series. Mathematicians do not see Zeno's Paradox as some kind of indication that the axioms of math are divorced from reality.
You'd have to look at the 'C' of ZFC set theory for that. The axiom of Choice has all kinds of fun implications, the Banach-Tarski Paradox for instance--the result that it's possible to cut a sphere into finitely many pieces, and rearrange those pieces to form two whole spheres.
And considering how seemingly mundane the axiom of choice is, I consider that result far more profound and puzzling than some argument involving turtles and halving distances repeatedly.
But as I say this is not my area of expertise.
But have you ever seen someone cut up an orange into two complete oranges? :P
A novel approach to solving world hunger, certainly.
I think that Evil is being quite reasonable. I mean there's many flavours and varieties of the correspondence theory of truth - some basic, some not so much. There are multiple manifestations of the coherence theory of truth. Pragmatic theories invoke related, but quite different theories of truth. And these are just the big-ticket items. If you try and say what it means for something to be "true" you explore and define the content of the concept you are working with. Different intelligent people have constructed theories of truth that reveal them to be using the word differently - showing differences between the content of the concepts they all name "truth" and showing that these differences are related to differences in many other fundamental concepts such as "mind", "matter", "intention", "external", "internal", "reality", and so on. And virtually all theories of truth proposed in philosophy (with the exception of a few outliers) have the benefit of accomodating most of the common use of the vague and loosely defined term "truth" that we use in daily conversation, and is perfectly good for our usual purposes. Where philosophy goes bad and becomes a waste of time (and this is what I think that Evil wanted to make sure didn't happen) is when people try to import common concepts into philosophical discussion that requries precise and well-defined concepts without making clear exactly how they are using the term.
Well, the Banach-Tarski cutting method is, itself, inherently non-physical, so I don't think you could really turn it into a problem for physics. It's only a problem for mathematicians if you don't like that result.
But mathematics is only based on the axioms of set theory in the same way that medicine is based on germ theory. Having it makes advanced applications possible and it's a much better description of what's going on than we previously had, but not knowing set theory didn't stop people doing math for millenia before it was invented. So most set theories seem to be based on some mathematicians not liking something about a previously existing one rather than actualy problems with it. It's not exactly a problem for anyone besides a certain portion of the mathematics community that ZFC doesn't allow for a universal set, for example.
Anyway, back to the topic...
It seems to me that saying that all truths are truths and that calling some relative and some absolute is semantics ignores a lot of things about the person making the statement. As MrMister pointed out, many "true" statements are based on imperfect knowledge, which in most non-trivial cases is going to be what people have. Beyond that are value and ethical statements, where the back-load going into the truth to make it absolute is just enormous and not really communicable by any means. It is arguably an absolute truth that "Ice cream is delicious" because I think it is when I say it, but there is no method to communicate the information required to qualify it into a statement which any reader at any time or place in the universe would agree is true.
I don't know where the dividing line is, but it seems like there must be a division between statements which are true for any observer provided a finite, communicable amount of qualifying data and statements which are not.
Statements of taste ('he's beautiful,' 'fish sticks are tasty'), epistemic modals ('possibly in the drawer,' 'might not rain,' 'probably arriving on time,'), and ethical claims ('murder is wrong,' 'one ought to donate') are all domains of discourse which people attempt to give relativist glosses; I just finished a class where we read some of the recent work by people like MacFarlane and Richard claiming that we need relative truth to make sense of the conversational data on the way that people offer and retract those sorts of claims. Of those, ethics is probably the most traditional area where people attempt relativist theories, and epistemic modals are the most recent trendy one.
Which is why I was sort of surprised by the earlier equation of relative truth with omitted information. Generally, philosophers don't want to relativize truth if they don't have to, and you most certainly don't have to in order to deal with omitted information. The areas where it looks like you might have to after all are not those dealing with omitted information, but rather those dealing with taste, epistemic modals, and ethics.
Edit: for the record, I'm not surprised that no one immediately mentioned relatively rarefied topics like epistemic modals, I'm more surprised that no one went for ethics off the bat.
But you just concluded that it isn't necessarily true, so why are you claiming that it makes sense to conclude that it's true?