By bouncing photons off it and measuring timings and frequency shifts. Its the fact the demon has to do some physical process which prevents it from violating thermodynamics. The entropy the demon produces by doing his measurements always exceeds the entropy lost by his sorting of particles. This is covered in any decent thermodynamics book's description of the thought experiment. I suggest you get your hands on one. After learning the basics required to even attempt to learn thermodynamics.
Is there a way to measure the position of the molecule without using photons? I already know the answer to this question, because I already know the demon has to do work ("some physical process") to gain information. That's why I've said just that a few times in this thread. If you don't believe me, you can find out if I'm lying (go have a look, duh). Selective blindness much?
Wait, wait, wait...Maxwell's Demon isn't real? I thought he lived in a basement in Geneva? Anyway, Arf, Maxwell's original demon possessed *divine* knowledge that resided outside of any logical, mathematical or physical means of obtaining it. Only later was it proven that any ACTUAL means of obtaining it (such as that described by AN above) would necessarily require more work than could be produced by the system and also produce a net increase in entropy that more than off-set the reduction in entropy achieved by the demon's sorting. Does that answer what you're getting at?
". . .a proof by Brillouin, Gabor, et al, that observing the molecule (so that, for instance a partition or barrier can be lowered and trap the molecule in one half) means the demon has to emit at least one photon and this must have an energy greater than the energy of the molecule. " Sorry, I shouldn't have posted this, that's Alphanumeric's job. I don't even understand what I was saying way back in post #12. (on the first page of this thread) Aha, the demon uses a divine function--well, that explains it! Not very convincingly, but, yeah. . .
So why are you asking? What purpose does asking the question serve, other than an attempt to change the subject from your complete lack of understanding in regards to basic terminology like 'function', 'continuous' etc. People in glass houses. So, to get back to the issue at hand.... Do you understand that the action of the demon can depend on the position and velocity of the molecule, ie the action is a function of position and velocity, yet position does not have to be a function of velocity nor vice versa? Do you understand that position can be a function of time and velocity can be a function of time but in such situations it is not automatic that position is a function of velocity or vice versa? If you don't understand why or you disagree say precisely what you don't understand or disagree with and why and I'll try to explain further.
I understand that to think a demon can open a trapdoor as a molecule approaches, means thinking a demon can see the molecule--its position and its velocity. I understand that a particle changes position because it has a velocity. I understand a particle can change position without changing velocity, but not why this is a "problem" for the demon. The demon can see the molecule change position, and it can see a melecule move towards the trapdoor (because molecules have a velocity). As established, whether this is physically possible, or mathematically possible is irrelevant, the function of the demon is logical (it's a product of logical thought), it doesn't have to be mathematical or physical. But then, unfortunately I have "complete lack of understanding in regards to basic terminology like 'function', 'continuous' etc. "
Is there a way to measure the position of the molecule without using photons? (Yes, there is a way, a mechanical way to do this with a modified Szilard device. Anyone who has studied it should know that) What is a reversible computation? Is computation a function, so it's a reversible function? Does entropy always increase, even in reverse computation? So, "you're" happy to answer questions, as long as the question appears to have something in it you can disagree with, so you can spend a few pages and multiple paragraphs pursuing it?
I suggest you do your own damn homework. There's lots of material out there about reversible computing.* After doing this, if you have some proper questions, I'll be happy to answer them. And, yes, I'm an expert. *Google is your friend. If you're interested in the link to thermodynamics and Maxwell's demon, Charlie Bennett has written some very nice stuff about this. Check out the Scientific American texts for some easy introductions.
It isn't a problem. I've already conceeded that that actions of the demon are a function of position and velocity. This has nothing to do with whether or not position is a function of velocity. You're lacking a basic understanding in this stuff and thus you don't realise that even if I were to grant your contentions in regards to the demon it wouldn't justify your original claim. I'll ask again... Do you understand that the action of the demon can depend on the position and velocity of the molecule, ie the action is a function of position and velocity, yet position does not have to be a function of velocity nor vice versa? Do you understand that position can be a function of time and velocity can be a function of time but in such situations it is not automatic that position is a function of velocity or vice versa? At least you can admit it.
It does if the demon can measure both the position and the velocity; if it has to predict the position of any molecule, how does the demon avoid knowing one if it knows the other? As far as the demon is concerned molecules have both, so how does it not use a "function"of velocity? The standard objection is that you can't write a function that, given a velocity, can return a position. But the demon can see the position and the velocity, as you say, so the demon "is" the function. But despite your claims, you haven't answered any questions, the questions in post#1 for instance. Not proper enough for you? You didn't say anything about this question, posted a long time ago: Why does Charles Bennett claim that it took new insights into theories of computation and the minimum energy required to compute something? So your suggestion that I google Charles Bennet is another funny joke, yes? You are a joke, too? Please don't lie about how happy you are. p.s. actually you're right about google, I've found a lot more using that than I could hope for from any place like this, that has a load of bullshitters in it. What this site has taught me though is that it pays not to believe much of what anyone has to say. For instance, nobody who has bothered to post anything believes anything much I've said. Hell nobody seems to believe I've asked any questions. If you are happy, I'm glad for you. This site isn't about discussing anything, it's about something else altogether. It isn't that difficult to work that one out, unless you're a moron.
You're really struggling with this I see. The demon's knowledge and actions depend on the position and velocity, ie they are functions of the molecule's position and velocity. That isn't the same as saying the position is a function of velocity. Its measurement method, such as bouncing photons off things, will give it both the position and the velocity but that doesn't mean the position is a function of velocity. I've already given you a situation where you know both the position and velocity of an object and yet the position is not a function of the velocity. There are a great many instances in mathematics where the existence of something can be proven even if its impossible to write it down. It's not that the function can't be written down, it doesn't exist. The distinction is important. That doesn't make the position a function of velocity. You simply are not grasping the definitions. So leave. If this place is such a waste, filled with idiots, why are you here?
Listen, many people here think they're the smartest guy in the room, but that obviously can't be the case. The reason you're getting beat up is because you're more arrogant than most with less ability to justify it. - You claimed you've been formally educated on entropy, but you haven't - You claimed you have "students", but you don't - You claimed, unbelievably, that those WITH a formal education (and at least one PHD) are idiots along with everyone else in this forum (except yourself of course) - Your beliefs about entropy include descriptions that are not only foreign to me, they are completely BACKWARDS to anything I've ever read - You won't say where you learned your "version" of entropy but you blindly demand that the rest of the world is wrong (W...T...F?) I've already said I'm willing to discuss all kinds of stuff but your responses are mostly monosyllabic versions of "Wrong." Are you really surprised that you aren't finding many participants interested in philosophizing with you?
I'm trying to show that some people have all kinds of ideas about information and what entropy is. See if you can refute the statement: "information entropy is a measure of the appearance of different symbols". Is it too general, or too poorly worded? Is it what I've been saying since page 1, or have I changed my story? Why did I predict there would be a problem? I don't feel like I'm getting beat up, but there are people here with certain problems--communication problems. Lots of people have problems like that. Can you suggest a reason that this question, also from page 1: What about the use of terms like algorithmic pressure and temperature? hasn't been beaten up? What isn't wrong with it?
I think it's a pretty simple thing. Any concept is also a function, so then do we conceive time and space as functions? What about motion? Is time a function of motion, in which case measuring motion means a clock must exist or "measuring" becomes meaningless? Is the whole position-velocity argument just a hill of beans? Because a demon can measure both, it can predict which molecules will approach the trapdoor. But does it have to measure both position AND velocity, really? Let's go over it once again: And way back when my statement first appeared, I was, I thought, still talking about the context of a demon, that will need to know three things about a molecule to predict if it's moving towards the trapdoor: an initial position, a second postion, and a direction. It has a function that can calculate, given two positions, the direction of a molecule. The velocity means there is one other argument needed, the time interval between the two measured positions. That's three 'inputs': two positions and a time, and two 'outputs', speed and direction. Whether the demon "sees" direction as a function of changing position, or sees position as a function of "motion", isn't all that important. But if the demon wants to sort molecules it has to be able to predict their motions, and "know" which ones are moving faster than others.
Too vague for practical use. The Shannon entropy definition talks about probability distributions, which gives it practical power. As a very superficial arm wavy definition I wouldn't say its wrong but I wouldn't use it myself. You're the guy who has, on more than one occasion, read something I've written and then claimed I said precisely the opposite. You're hardly a model of communicative abilities. Because they are not well defined or even coherent. I previously asked you to define things you've said because you either make up your own terminology or you butcher pre-existing terminology. Can you define 'algorithmic pressure' and 'algorithmic temperature' for me please. Functions of what? Is 'sad' a function? Is 'five' a function'? Is 'god' a function? 'Function' has several meanings, which one means that all concepts are functions. Motion is a function of time, not time is a function of motion. Time can exist without motion, motion cannot exist without time. It needs to know the velocity to know which molecules to let through. It needs to know the position as well to work out when the molecule will get to its door and thus when to open and close the door. If all you knew were velocities you'd not know when to open and close the door as you'd not know where the fast moving molecules were. Yes, two positions gives you a direction, you just draw a line through the two positions. Thus you can regard direction as a function of two points. If your inputs are two positions and time then by construction your velocity motion value is a function of two positions. That still doesn't mean position is a function of velocity. Are you at any point going to try to make your case for your claim or are you going to continue just rambling about the irrelevant demon example?
The one that stops you saying "time isn't a function". If this is true then time isn't a concept. Or, firstly prove that a concept is not a function and so the concept of time cannot be either. Good luck with that. Someone else got there before me, so I don't even have to try. "The algorithmic temperature, T , is roughly the number of times you have to double the runtime in order to double the number of ways to satisfy the constraints on length and output [of an ensemble of programs]. The algorithmic pressure, P, measures the tradeoff between runtime and length [4]: if you want to keep the number of ways to satisfy the constraints constant, then the freedom gained by having longer runtimes has to be counterbalanced by shortening the programs. This is analogous to the pressure of gas in a piston: if you want to keep the number of microstates of the gas constant, then the freedom gained by increasing its energy has to be counterbalanced by decreasing its volume." http://arxiv.org/abs/1010.2067v1
So your definition is whatever one makes you right. Please Register or Log in to view the hidden image! And what if no such definition exists? You have yet to demonstrate all concepts are functions. What precisely do you mean by 'function' in this context? Some concepts have functions, in that they have a particular purpose. Some concepts are functions of other concepts, for instance a vector field is a concept and elements in the vector field are functions of the location in the base manifold. Is 'sad' a function? How so? God? Five? Hard? Angle? Explain precisely how time is a functionm or any other one of those concepts I just listed. And you can't do it by just saying "all concepts are functions" because you have yet to demonstrate that. I asked you this in my previous post, I gave a couple of examples of concepts and asked you to explain how they are functions. If you're unwilling (or more likely unable) to discuss things in an honest manner you're not exactly taking the high ground in the thread. You made a claim, I ask you to elaborate, you fail to do so and then just reassert your assertion. Do I need to explain to you why that isn't a way to demonstrate the validity of your claims? So you know that the terms exist within the mainstream literature and yet you're asking why no one has objected to them? I didn't join the thread till page 2, I didn't see you post them.
You have yet to demonstrate the existence of a function which cannot be conceived, that is that a function exists which is not a concept. That's you and the rest of humanity. Measuring time is a function of clocks. Clocks are constructed according to our concept of time. Is time something physical when it's measured? "An interval of time" is a concept--there is no proof that such things really exist. But measurement is real, clocks measure time because of motion--a clock with no moving parts isn't going to measure anything. Hmm. Oh well, now you can explain why you object, or don't object to some terms in the mainstream literature.
You've made a basic mistake in your logic. What you've just said is that I need to provide a function which is not a concept, ie you're claiming all functions are concepts. But what you were saying before is that all concepts are functions. For instance you said "I think it's a pretty simple thing. Any concept is also a function". So which is it? Are you claiming all concepts are functions or all functions are concepts? The latter is true, all functions are concepts. However not all concepts are functions and its that which pertains to your original claim. I'm trying to work out if you're really so incoherent in your thoughts you honestly contradict yourself and say completely opposite things accidentally or whether you're just a troll. Yes, the function or purpose of a clock is to measure time. This meaning of 'function' does not relate to your original claim that position is a function of velocity, as it is meaningless to say the purpose of velocity is position. The nature of time is something philosophically open to debate and since its utterly irrelevant to your claims about position being a function of velocity there's no point in us going off on another tangent. Try to marshal your thoughts a little better and actually present something relevant to your claim. None of which has anything to do with you demonstrating your claim or answering my questions. What?! You want me to explain why I do or don't object to some mainstream terminology? What possible purpose does that question have? Algorithmic temperature and pressure are irrelevant to your claims. Whether or not I do or don't object to the terms is irrelevant. Your question is pointless because you aren't responding to anything I've said, you're just asking me to explain my view, a view which I haven't even stated. How about you stop trying to change the topic and answer my questions? I'm asking you relevant questions which pertain to your claims. My posts are more relevant to your claims than your own posts! I'll make it simple for you, here's some direct questions : 1. Do you understand that position can be a function of time and velocity can be a function of time but in such situations it is not automatic that position is a function of velocity or vice versa? 2. Do you understand that even if all functions are concepts that doesn't mean all concepts are functions? If you think all concepts are functions explain how 'hard' is a function. If you can't justify your original claim at least have the intellectual honesty to admit it.
That's a really fine distinction though. If you conceive anything, you are "performing" a function. Can you give an example of a concept which isn't a function? Is "hard" a function? It depends on the existence of other concepts. Diamonds are hard, physics exams are hard. There is no such thing as a concept that 'stands alone", all concepts require the existence of other concepts, and all concepts are functions. Ask Frege. You might say that "god" is a concept which is not a function. But not a function of what other concepts/arguments? My claims about there being a TOE, which is based on the concept of an algorithm that prints a "universe"? Or you mean the claims you've targeted and pursued for several pages, and not any of the claims/questions I've asked about anything else? So this thread is about your claims about my claims, then? My original claim. that position is a continuous function of velocity was wrong, I openly and honestly admit that. Ok, now? My other claim, that this is irrelevant to Maxwell's demon is not wrong. The demon as you say, is an irrelevant argument, except it's an argument that has stayed relevant for over 100 years. Why is an irrelevant argument still relevant? Are scientists just dumbasses?
