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How does this prove that gravity is not an emergant phenomena? Doesn't this only claim that gravity and entropy don't have some type of a first order (direct)

How does this prove that gravity is not an emergant phenomena? Doesn't this only claim that gravity and entropy don't have some type of a first order (direct) relationship? Rant: I never understood how you can explain gravity as 1) a bending of space-time caused by mass and then 2) pretend it's a force transmited by "gravitons". If 1) is true then it's an effect (phenomena), not a cause (force). If 2) is true than it's a cause (force), not an effect (phenomena).

nutjob123 15y ago
This article does not claim to "disprove that gravity is not an emergant phenomena" it claims to prove that gravity is not an emergant phenomena
- powertower 15y ago
  Fixed the double negative.
Xlythe 15y ago
A phenomena is the summation of several causes. Even if gravity is a phenomena, there are still the causes for it to look for. And if it's not, well then we still have to find the single cause. We don't even have that. What strikes me as odd is that entropy dictates things eventually break away from each other while gravity pulls things closer. The two are at odds with each other. And that entropy is a phenomena itself.
- troels 15y ago
  Phenomena is plural of Phenomenon.
mattheww 15y ago
No, this paper claims that introducing gravity as an emergent phenomenon in Verlinde's framework breaks quantum mechanics. He shows that Verlinde's proposal changes the Hamiltonian. However, the solutions to the standard Schrodinger equation have been measured in experiments with ultra-cold neutrons and shown to agree (ergo, disagreeing with Verlinde's theory). Regarding your "rant": either way, it's still a force. Gravity still causes things to move. How that force is explained is clearly different in different theories. General Relativity suggests (1). Quantum Gravity theories suggest (2). Newton didn't really explain how it was mediated. You could apply the same rant to QED: Either electrodynamics is caused by the bending of a vector potential by electric charge or it's a force transmitted by photons. The two statements are equivalent. But with gravity, we're not sure if quantum part is true.
sipior 15y ago
The same way you can explain electromagnetism as a field throughout space-time, and then pretend that it's a force transmitted by photons. Feynman once famously claimed that no one really understood quantum mechanics, if that makes you feel any better; I'm not sure that's strictly true, but perhaps we've simply defined understanding down a bit :-) Usual disclaimer about the pending detection of the graviton, etc, etc. Your last sentence draws an arbitrary distinction between a "force" and a "phenomenon" which does not appear to be borne out in reality, and if I may say so, is at the heart of your trouble understanding why both 1) and 2) are correct.
- deleted 15y ago
  [deleted]
niklasl 15y ago
Pictures 1 and 2 are equivalent. See chapter 18 in Misner, Thorne, Wheeler. We can't distinguish a universe where space is bent by mass from one with flat space-time that has a massless spin-2 particle (a graviton). The flat space-time in the latter case would be unobservable in principle.
vinutheraj 15y ago
Feynman has expressed his opinion on this in one of the Messenger lectures on the Character of Physical Law that he gave at Cornell. This is an example of the wide range of beautiful ways of describing nature. When people say that nature must have causality, you can use Newton's law; or if they say that nature must be stated in terms of a minimum principle, you talk about it this last way; or if they insist that nature must have a local field - sure, you can do that. The question is: which one is right? If these various alternatives are not exactly equivalent mathematically, if for certain ones there will be different consequences than for others, then all we have to do is to experiment to find out which way nature actually chooses to do it. People may come along and argue philosophically that they like one better than another; but we have learned from such experience that all philosophical intuitions about what nature is going to do fail. One just has to work out all the possibilities, and try all the alternatives. But in the particular case I am talking about the theories are exactly equivalent. Mathematically each of the three different formulations, Newton's law, the local field method and the minimum principle, gives exactly the same consequences. What do we do then? You will read in all the books that we cannot decide scientifically on one or the other. That is true. They are equivalent scientifically. It is impossible to make a decision, because there is no experimental way to distinguish between them if all the consequences are the same. But psychologically they are very different in two ways. First, philosophically you like them or do not like them; and training is the only way to beat that disease. Second, psychologically they are different because they are completely unequivalent when you are trying to guess new laws.

nutjob123 15y ago

This article does not claim to "disprove that gravity is not an emergant phenomena" it claims to prove that gravity is not an emergant phenomena

powertower 15y ago
Fixed the double negative.

Xlythe 15y ago

A phenomena is the summation of several causes. Even if gravity is a phenomena, there are still the causes for it to look for. And if it's not, well then we still have to find the single cause. We don't even have that. What strikes me as odd is that entropy dictates things eventually break away from each other while gravity pulls things closer. The two are at odds with each other. And that entropy is a phenomena itself.

troels 15y ago
Phenomena is plural of Phenomenon.

mattheww 15y ago

No, this paper claims that introducing gravity as an emergent phenomenon in Verlinde's framework breaks quantum mechanics. He shows that Verlinde's proposal changes the Hamiltonian. However, the solutions to the standard Schrodinger equation have been measured in experiments with ultra-cold neutrons and shown to agree (ergo, disagreeing with Verlinde's theory). Regarding your "rant": either way, it's still a force. Gravity still causes things to move. How that force is explained is clearly different in different theories. General Relativity suggests (1). Quantum Gravity theories suggest (2). Newton didn't really explain how it was mediated. You could apply the same rant to QED: Either electrodynamics is caused by the bending of a vector potential by electric charge or it's a force transmitted by photons. The two statements are equivalent. But with gravity, we're not sure if quantum part is true.

sipior 15y ago

The same way you can explain electromagnetism as a field throughout space-time, and then pretend that it's a force transmitted by photons. Feynman once famously claimed that no one really understood quantum mechanics, if that makes you feel any better; I'm not sure that's strictly true, but perhaps we've simply defined understanding down a bit :-) Usual disclaimer about the pending detection of the graviton, etc, etc. Your last sentence draws an arbitrary distinction between a "force" and a "phenomenon" which does not appear to be borne out in reality, and if I may say so, is at the heart of your trouble understanding why both 1) and 2) are correct.

deleted 15y ago
[deleted]

niklasl 15y ago

Pictures 1 and 2 are equivalent. See chapter 18 in Misner, Thorne, Wheeler. We can't distinguish a universe where space is bent by mass from one with flat space-time that has a massless spin-2 particle (a graviton). The flat space-time in the latter case would be unobservable in principle.

vinutheraj 15y ago

Feynman has expressed his opinion on this in one of the Messenger lectures on the Character of Physical Law that he gave at Cornell. This is an example of the wide range of beautiful ways of describing nature. When people say that nature must have causality, you can use Newton's law; or if they say that nature must be stated in terms of a minimum principle, you talk about it this last way; or if they insist that nature must have a local field - sure, you can do that. The question is: which one is right? If these various alternatives are not exactly equivalent mathematically, if for certain ones there will be different consequences than for others, then all we have to do is to experiment to find out which way nature actually chooses to do it. People may come along and argue philosophically that they like one better than another; but we have learned from such experience that all philosophical intuitions about what nature is going to do fail. One just has to work out all the possibilities, and try all the alternatives. But in the particular case I am talking about the theories are exactly equivalent. Mathematically each of the three different formulations, Newton's law, the local field method and the minimum principle, gives exactly the same consequences. What do we do then? You will read in all the books that we cannot decide scientifically on one or the other. That is true. They are equivalent scientifically. It is impossible to make a decision, because there is no experimental way to distinguish between them if all the consequences are the same. But psychologically they are very different in two ways. First, philosophically you like them or do not like them; and training is the only way to beat that disease. Second, psychologically they are different because they are completely unequivalent when you are trying to guess new laws.