What is Demon: Definition and 38 Discussions

A demon is a supernatural being, typically associated with evil, prevalent historically in religion, occultism, literature, fiction, mythology, and folklore; as well as in media such as comics, video games, movies, anime, and television series.
In Ancient Near Eastern religions and in the Abrahamic traditions, including ancient and medieval Christian demonology, a demon is considered a harmful spiritual entity which may cause demonic possession, calling for an exorcism. Large portions of the Jewish demonology, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and were transferred to Judaism during the Persian era.In Western occultism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled. The supposed existence of demons remains an important concept in many modern religions and occultist traditions. Demons are still feared largely due to their alleged power to possess living creatures. In the contemporary Western occultist tradition (perhaps epitomized by the work of Aleister Crowley), a demon (such as Choronzon, which is Crowley's interpretation of the so-called 'Demon of the Abyss') is a useful metaphor for certain inner psychological processes (inner demons), though some may also regard it as an objectively real phenomenon.
The original Greek word daimon did not carry negative connotations. The Ancient Greek word δαίμων daimōn denotes a spirit or divine power, much like the Latin genius or numen. The Greek conception of a daimōn notably appears in the works of Plato, where it describes the divine inspiration of Socrates.

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  1. N

    Particle Maxwell's demon full experiment description

    Hey! Does anyone have the large/full description of Maxwell's demon thought experiment? I've read it on Wikipedia, but I was wondering if someone knows a better source I can reach legally. Thanks.
  2. L

    I The Job of the Demon: Compressing Gas Without Work

    Suppose we have a cylinder with one wall guard by a demon. Inside is one gas molecule moving left and right for simplicity. Now we want to closer the wall (compress the gas) without doing work. The job of the demon is push the wall closer when the gas move left and lock the wall when the gas...
  3. Eric Bretschneider

    Is Maxwell's Demon Limited by Energy Required for Door Movement?

    Physics students are taught about Maxwell's demon and how by opening and closing a door between two chambers filled with gas. If the demon opens and closes the door to "concentrate" low energy molecules on one side and high energy molecules on the other side he can create a temperature...
  4. iVenky

    I Maxwell's Demon and the Uncertainty Principle

    Maxwell's demon measures the position and velocity of the particle. How can it do that when it violates the uncertainty principle? Does that mean uncertainty principle is unavoidable otherwise we will violate II law of thermodynamics as in the case of Maxwell's demon?
  5. P

    Is this another Maxwell's demon?

    A though experiment: We have two gas chambers at the same temperature and pressure, separated by a wall punctuated by very small pores. Let's say small enough to allow the pass of only a few gas molecules at a time (so, no complex interactions between gas molecules inside the pore). These...
  6. M

    Ending global warming with Maxwell's demon

    As a start for discussion I'd like to make the following bold claim: Both the problems of enough usable energy and global warming can be resolved by implementing Maxwell's demon on a large scale. To justify this bold statement somewhat, I'd like to point to a (relatively) recent...
  7. Deepblu

    Maxwell's Demon Paradox: Solving the Puzzle Without Memory Requirements

    The resolution for Maxwell's demon paradox is that the demon has limited memory and the demon will eventually run out of information storage space and must begin to erase the information it has previously gathered. Erasing information is a thermodynamically irreversible process that increases...
  8. bland

    I have a problem with Maxwell's demon

    The problem I have is that I fail to see how it caused so much consternation. The way I understand it the demon could passively allow or not allow particles of gas to pass or not pass, and thus gradually create a more ordered state free of charge. I have learned that the problem with the demon...
  9. R

    Is Maxwell's Demon Still an Unsolved Mystery?

    https://en.wikipedia.org/wiki/Maxwell%27s_demon, Is this solved, or any new ideas about it?
  10. G

    Does Laplace's demon know about entropy?

    Hi. I read this thread with great interest and have similar question: In a deterministic universe, does entropy exist for Laplace's demon? Since he knows the universe to it's microstate, does the term "macrostate" even make sense to him? And say there is a "half-demon" that only knows the...
  11. ramzerimar

    I Laplace's Demon and determinism

    Not sure if this is the correct forum to post this thread, but here we go. I'm a layman in physics and mathematics, and recently, I was reading about the Laplace's Demon and how, according to classical mechanics, the future could be entirely determined if some entity (the Demon) could have...
  12. H

    An Implementation of Maxwell's Demon

    http://physics.aps.org/articles/v8/127 It uses energy so it doesn't break any laws.
  13. KMote

    Does Maxwell's Demon violate the 2nd Law of Thermodynamics

    I'm a newbie (obviously), but I just read this recent paper describing an "experimental realization of an autonomous Maxwell’s demon" (along with this review). I think I understand the general concept of Maxwell's thought experiment well enough (from a layman's perspective), but I'm having...
  14. gre_abandon

    Demon algorithm for microcanonical ensemble

    I simulated a microcanonical ensemble of 10 ideal gas particles in one dimension and yielded the expected normal distribution of velocities. However, I still did not get how the algorithm works. The demon has non-negative energy content and the demon together with the system constitutes a closed...
  15. Rickswan

    Realistic demon physiology and weapons against them

    This thread is also my introduction to the forum, so hello. So the basic setup of my story is the hordes of hell invade New York City. I'm agnostic, so it's more "beings from another dimension enter ours" than a religious thing - it's like the DOOM game series. Let's say that a certain amount...
  16. fezster

    Where Can I Find Good Books on Maxwell's Demon?

    Can anyone recommend any good reading on Maxwell's demon? I'm mostly looking for things at the undergraduate level, but I don't mind something less rigorous or more advanced. (Apologies to the mods if this is in the wrong forum.)
  17. S

    Maxwell's demon - a new concept

    Could somebody disprove the following concept of a Maxwell's demon: Let's say we have a very small container, the size and a form of a nanotube, similar to ellipse, and only two gas molecules randomly flying inside. According to probability we will quite often find molecules in the different...
  18. L

    Scaling Maxwell's Demon Experiment: Macro-Level Rigid Ball Suspension

    I had the concept of scaling up Maxwells' demon experiment to a marco scale. Replacing molecules of gas with light, rigid, balls. Perhaps coated in magnets with varying poles so they never touch (non-interacting). Would suspend them in a thin fluid with neutral buoyancy.
  19. M

    Laplace's Demon: Quantum Mechanics & Determinism

    Laplace’s demon knows all forces and “positions of all items of which nature is composed” and enjoyed the knowledge of the future just like the past to be “present before its eyes”. Acording to Wikipedia, also the source of the first quote, “Due to its canonical assumption of determinism...
  20. K

    Maxwell's Demon: would a cone work?

    Maxwell's demon is the little guy who opens an atomic door to a container to let atoms fly in, but shuts it before an atom flies out, thus increasing the internal pressure. Suppose the walls of a container had several small cone-shaped holes built into it. The inside hole might be pretty...
  21. ThomasT

    Random thoughts on Maxwell's demon

    This just came into my head. I don't think I really understand the significance of Maxwell's demon. Please don't try to explain it to me. It's just a random thought.
  22. A

    What is the connection between Maxwell's Demon and Liouville's Theorem?

    Hi Folks, (Skip to next paragraph if you already know what M's D is.) Maxwell's demon was a counterargument to the second law of thermodynamics (and hence the first) involving two chambers of air connected by a trap door which this demon would open and close to let fast molecules go one way...
  23. W

    In regards to Maxwell's Demon

    In regards to "Maxwell's Demon" In regards to the Maxwell's Demon thought experiment and violation of the Second Law of Thermodynamics, I have a scenario that results in (a) question(s). First I won't pretend to have extensive knowledge of Thermodynamics so bear with me... Say we have two...
  24. B

    Maxwell's Demon via molecular reed valves can produce work?

    Well not literally The Maxwell's Demon... If a one-way reed valve can be brought down to size of only a few molecules, don't you think it could allow passage of a gas molecule across a barrier in one direction only? How I think it could work: -The small size (molecular) of the valve is...
  25. T

    Maxwell's Demon Thought experiment

    I recently just heard of this thought experiment where two rooms/resoviors whatever you want to call them are adjoined by a door that a little demon controls. Both rooms have the same temperature, The demon then opens this door when particles with higher kinetic energy are nearby to let them...
  26. K

    Maxwell's Demon: Exists, Hard at Work at Phase Interfaces

    In his famous thought experiment of 1867, James Clerk Maxwell postulated a creature (later called a “demon” by Lord Kelvin) who could discern the speeds of gaseous molecules and who could pass selected molecules through a partition or deny them passage on the basis of those speeds. The essence...
  27. S

    Why diode is not demon of Maxwell?

    Diode should conduct electrons in one direction only. Why doesn`t it produce power at ambient temperature or any temp.?
  28. W

    Maxwell's Demon: Chance of Violating the 2nd Law?

    http://en.wikipedia.org/wiki/Maxwell%27s_demon" when i read this i was wondering, what if the deamon accuires no information at all and just shoots blind by guessing wherever a approaching particle is A or B.. in most cases the demon would end up with a no separation, but if its lucky...
  29. D

    David Wolpert "Slams Door" on Laplace's Demon

    On the Wikipedia page about http://en.wikipedia.org/wiki/Laplace%27s_demon" , it says "In 2008, David Wolpert used Cantor diagonalization to "slam the door" on Laplace's demon." I'm not sure what that means.
  30. fluidistic

    Understanding Entropy: Exploring the Variant of Maxwell's Demon

    Hi, I've not covered yet the Second's Law of thermodynamics so I don't understand it well. A friend of mine talked to me about Maxwell's demon and now I have the following question : Imagine a planet such that its escape velocity is about Earth's one, but without any atmosphere. Now imagine...
  31. R

    Maxwell's Demon: Clarifying Arguments Against 2nd Law

    With my little reading on the subject (after listen to the argument in Stat.Mech. class a year ago), I am asking for help on clarifying the following points: The arguments against such a system violating the 2nd law focus on the two processes that would increase the entropy of the system...
  32. Loren Booda

    Nanotechnological Maxwell's demon?

    Has nanotechnology had any success in mechanically separating "cold" atoms from "hot" ones, an application first dreamt up by Maxwell in the late 1800s?
  33. D

    Maxwell's Demon: Is it Worth the Read?

    Maxwell's Demon by Hans Christian and Von Baeyer, for those who've read it, is it worth reading?
  34. T

    Has demon possession been researched?

    Has demon possession been researched? Did science find anything convincing?
  35. K

    Maxwell's Demon: What Do You Think?

    This came up in another topic, but rather than talk on about it there, I created a new thread as it would be too far off subject for the said other thread. I don't see the big deal about "Maxwell's Demon". Assuming the walls and everything in the system are perfect insulators, wouldn't...
  36. X

    Maxwell's Demon: An Energy Conversion Experiment

    Maxwell’s Demon An Energy Conversion Experiment in Contradiction to the Second Law We have performed successfully an experiment of energy conversion of a totally new type. Please see the attachment figures. The experiment relates to a special electronic tube, which has two similar and...
  37. S

    Maxwell's Demon Possibility?(Entropy)

    "Maxwell's Demon" Possibility?(Entropy) About a hundred years ago, James Clerk Maxwell imagined 2 adjacent chambers, each containing gas and both sealed to the outside world. The chambers are also sealed from one another, except for a single gate the size of a gas molecule. Guarding this gate...
  38. M

    “The Demon Haunted World”, by Carl Sagan review

    "DEMON HAUNTED WORLD", SAGAN - a CRITIQUE “The Demon Haunted World”, by Carl Sagan A Critique by MirabileAuditu The late Carl Sagan built a considerable reputation, and fortune, writing such books as “Cosmos”, “Pale Blue Dot”, and “The Demon Haunted World”. In each of them, he pretends...