Originally Posted By: Bill

Now here Motl seems to be to be saying that for larger systems, such as life, there is no visible difference between classic and QM entropy.

Ok what he is saying is generally QM will approximate the classic theories at large scales we call it the correspondence principle.


=> In physics, the correspondence principle states that the behavior of systems described by the theory of quantum mechanics (or by the old quantum theory) reproduces classical physics in the limit of large quantum numbers. In other words, it says that for large orbits and for large energies, quantum calculations must agree with classical calculations.

Now there is a qualification here that the original theory was firstly correct and secondly being a classical theory it is an approximation and it may violate in the quantum domain. Think about Newtons laws with GR for example.

One of those two options seems to be failing with Gibbs free energy when used with biological life sciences unfortunately rewritting all this in relative entropy equations to check it is not trivial it's the sort of thing that one does for a doctorate. All I can tell at the moment is something is failing and others have clearly identified the same problem. The problem is compounded for me because I don't do biology I could probably attempt the check of Gibbs free energy for a straight chemical reaction in chemistry but thats not very helpful.

It will take probably a decade more for modern QM theory to successfully role out and check all our classic physics it isn't going to happen overnight.

Originally Posted By: Bill

Why would organisms always get more and more complex? It doesn't seem to me that they have to get more complex, they can just change. After all, they just have to know about their current environment, not what it was earlier. If they can handle the current environment they don't need to know how to handle the previous one, so they can forget it. Also the quote you give says they come into evolutionary equilibrium, not quantum equilibrium. I don't see that those are the same things at all.

Ok I will break this apart there are several ideas.

Firstly to store quantum information it must pack into a quantum spin. How that spin is encoded by the organisms DNA we don't have to get involved in it will be very complex. DNA will only have the ability to encode a certain number of spins per base pair and it may not even be per base pair it may need sequences that is all biological stuff I don't study perhaps ImagingGeek knows. I think it has something to do with protein foldings or something like that.

Essentially this becomes like computer bits where an 8 bit byte on a computer can only encode 256 discrete values.

Now your argument that the organism can stay the same is the same as saying I can hold a computer byte to a set value. I can do any problems I like so long as I don't require more than 256 different values.

The problem becomes the moment I need to add in a 257th entry I need to expand the information base and on a computer you could jump to a 9th bit but for simplicity they don't they jump to 16 bits.

See the same problem happening here computers as they evolve will get more and more complex because they are trying to deal with describing more complexity. Infact processor op-code sets similarly tend to bloat as well and we take that up with the next point.

Now lets talk about forgetting history and that too has a computer equivalent. Some 16 bit computers predominately RISC's drop the support for ever picking up or dealing with 8 bit Bytes they always work with 16 bits simply zeroing off the top 8 bits in what would have been an old byte instruction. What is imporatant here is they evolve by learning what they can ignore from history because it is no longer important and that implies intelligence smile

Now you may argue that there is no similarity between computer evolution and life but at this level there is and here is why.

When we started designing computers we had no idea of the end goal of what they would be expected to do. Thus the computer evolution is simply meeting the needs for taking the next step of complexity thus everything in a computer core continues to expand instruction bit width and memory.

Quantum information theory basically says the same sorts of things about the universe if we don't know the outcome from start the the system with head towards a state of more information.

For animals to evolve ergo they must encode more information or else they violate this central tennant of QM or don't evolve take your pick.

Now you may want to argue that evolution has stopped I can even tell you how to test it smile

I had not thought about life and QM much at all until I saw this thread and realised it.

Again I want to point out QM is not having anything to do with driving or being involved with evolution it is simply a description of what is happening and so long as life evolution is encoding more information it is not in violation of QM and the universe. ERGO life must continue to get more information complex to continue to evolve.

The bad news for creationists is that the system is acting as if it does not have a known endpoint or what you would call classically acting like an open system. Life is also acting like every other part of that system and thus is not special in any way.

Last edited by Orac; 03/12/13 08:34 AM.

I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.