04 November, 2010

Conservation of Information - meh!

This post is an expansion of a comment I left over at SMRT a while back. The topic was 'information' and whether or not it can be considered as a measurable quantifiable 'thing'. As stated by WEM in the OP:

There are a bunch of conservation laws (energy, momentum [angular and linear], electrical charge, etc); simply put, the value of X in a closed system will be unchanged no matter how that system changes.

It seems to me that Christian fundamentalists are trying to get "Information" added to the list. Although the devil's in the details (re. the definition of "information", whether a system is open or closed, etc), the idea is that it requires an external agent (ie. God) to introduce information to a system.

So is the total amount of information conserved? Is information an objective 'thing' that can be used by Creationists as some sort of proof for their God?

Here's my take on it...

Since different people can glean different information from the exact same source, this means that the very existence of information is subjective. It is fallacious to say that 'the information is there, you're just not seeing it', because that would leave open the possibility that there is additional information present which nobody has seen, and hence this refutes the notion that there is a quantifiable amount of information in the first place.

There could always be more information.

If two people are watching a documentary, they are taking in information. However, if one of them falls asleep before the end, the amount of information in the universe will be less than what would have existed had they both stayed awake. Thus, it is impossible to assign a tangible value to the amount of information in any system at any time, and so it is also impossible to definitively state whether it has increased or not - the amount of information might have increased for one observer but decreased for another.

The following scenario shows what I mean...

Two men watch a library and all its original contents (no other copies) burn to the ground. The first man observes a loss of information as hundreds of thousands of original books are incinerated. Most people would probably agree with this man. However, the second man, who is not interested in literature, observes an increase in information because he is an arsonist and has thus gained plenty of information from the experience. Who is to say that more information was lost than gained? What if 2 arsonists gleaned information from the fire? Would that mean that twice as much information was gained? If so, what if a billion arsonists were watching? By increasing the amount of arsonists watching, at some point in theoretical space more information would have been gained than lost. The same can be demonstrated the opposite way too, meaning information is subjective and can't be quantified or said to have definitively increased or decreased.

I'm not claiming that this example proves anything - I don't know enough about this subject and I imagine the definition of information is fuzzy at best. However, it does seem to suggest that information is not an objective thing that can be used to prove the existence of a God; eh sorry, I mean of an Intelligent Designer.


Pvblivs said...

     I have to say that you went in a rather different direction than I expected. Usually, when I hear of "conservation of information," it is to say everything theoretically measurable about the universe could be represented as a clump of bits. The "skin" of a "black hole" would be a set of bits each occupying a type of Planck area unit. This, incidentally, makes no distinction between useful and useless information. The contents of the original books is still maintained in the resultant pattern of smoke and ash. It is just unrecoverable to us. I had never heard of christians trying to invoke information theory.

rhiggs said...


Even if it were possible to represent everything as a clump of bits, surely this doesn't guarantee a conservation of information - this would be a conservation of matter/energy. All the information in the universe would include people's memories and abstractions, which I am suggesting is unquantifiable. Theroetically, perhaps all of this could also be represented as bits, but it is certainly not conserved (it can increase and decrease). The bigger the population, the more combined information is contained in people's memories and abstractions. If the human race began to die off, this combined information would decrease.

"The contents of the original books is still maintained in the resultant pattern of smoke and ash. It is just unrecoverable to us."

Yes, in terms of energy/matter. But not in terms of information. There is far more information in a library full of books than in a pattern of smoke. For example, all of the books could have been empty (blank pages) and the pattern of smoke would have been the same, or at least equally as informative. Thus, the vast amount of information contained in the books is simply lost. It is not still present in the smoke.

"I had never heard of christians trying to invoke information theory."

William Dembski certainly invokes information theory:

Intelligent Design as a Theory of Information

Talk Origins have a response to it here. I really don't know enough about the subject though so I'm not sure if my critique even applies to Dembski's argument, which concerns Complex Specified Information (which itself is disputed).

Pvblivs said...

     I don't deny that christians are (mis)using the idea. I had simply not run across that. I've seen them misuse plenty of other ideas. No, this link gives a better description of what I have seen regarding the idea of conservation of information, and its own uncertainty.

rhiggs said...

Interesting article, although I wonder if it is now outdated (1998)? Personally, I can't see how information must be conserved (see my last comment re the library books). This, of course, doesn't mean I am right, but it's nice to see that Stephen Hawking seems to agree with me...!

Pvblivs said...

I didn't notice any more recent findings. Even if they decide the conservation of information is wrong, that article is useful for understanding the idea. My own thoughts are that black holes can't actually form. Large massive bodies emit Hawking radiation without ("yet") being black holes and this radiation will eventually cause the mass to dissipate before ever achieving black hole status. In other words, the leak doesn't exist.