ASA - April 2007: Re: [asa] Information and knowledge

From: Randy Isaac <randyisaac@comcast.net>
Date: Mon Apr 09 2007 - 22:39:43 EDT

Bill,
All quibbling is welcome! Quibble away. These concepts aren't easy to understand and I'm a long way from understanding it. I may well be way off base in my understanding of it. I'm more than happy to get in touch with the information science group back in Watson to get clarification on any of this. I'm just trying to convey what I have learned. Or think I have.

It is true that the genome resembles a computer program to some extent. Actually I think we impose that resemblance in our attempt to understand the genome. It is human nature to use familiar concepts to interpret new observations.

The conveyance of instructions or data is a result of the replication process. That is indeed a marvel of creation. Understanding the origin of self-replication is tantamount to understanding the origin of life. But that doesn't determine what is information and what is complexity. By the way, I'm not sure it's proper to say "the genome contains complexity" in the same way that we would say a "memory chip contains information." I would rather say that the genome is characterized by a complexity that is transferred in two ways. One is in its entirety during cell replication. The other is piecemeal during protein formation. We commonly use the term "information" to characterize what is transmitted. That's ok but just realize that this is a different type of "information" than Shannon-information. The same rules don't apply.

Yes, k is Boltzmann's constant and T is the temperature of the system that embodies the information.

Randy
  ----- Original Message -----
  From: Bill Hamilton
  To: Randy Isaac ; asa@calvin.edu
  Sent: Monday, April 09, 2007 9:11 AM
  Subject: Re: [asa] Information and knowledge

Randy wrote

This also leads to an important observation on the 'information' in the genome. Charles Bennett once gently corrected me, saying that technically, the more accurate term is 'complexity' not 'information.' The genetic code conveyed from one cell to its replicated cell is not 'information' as Shannon described. This 'information' is not independent of its physical embodiment. The physical embodiment IS the information. It is never converted from one medium to another. This is really complexity, not information. The supposed notions of conservation of information don't apply to the genetic code. It is not a message conveyed from one agent to another. Information about the genome and its sequence of course is classical information.

I have to quibble with this. Evidently this distinction depends on the three points you stated at the beginning of your post:

  1. Information is physical
  2. Information is independent of its physical embodiment
  3. Erasing one bit of information dissipates at least kT/2 of energy

However, these points seem to leave out what information _is_: symbols organized in such a way that they convey instructions or data. To say that the genome contains complexity instead of information leaves out (IMO) this characteristic. The genome resembles a computer program that specifies an algorithm for building cellular structures. And that to me is something more specific than complexity.

BTW, in point 3 I presume k is Boltzmann's constant. Is T the temperature? And if so what temperature does it represent? Some latent heat required to record the bit? The ambient temp? ...?

  Bill Hamilton
  William E. Hamilton, Jr., Ph.D.
  248.652.4148 (home) 248.821.8156 (mobile)
  "...If God is for us, who is against us?" Rom 8:31

  ----- Original Message ----
  From: Randy Isaac <randyisaac@comcast.net>
  To: asa@calvin.edu
  Sent: Sunday, April 8, 2007 7:17:50 PM
  Subject: [asa] Information and knowledge

Having finally worked my way through the mountain of posts from the last three weeks, I'd like to comment on a couple. There were several references to information, its mass and energy, and its relationship to the genome. Maybe we should remind ourselves of some of the fundamental principles of information.

Claude Shannon was the key pioneer of information theory. Rolf Landauer may have done the most to turn it into a bona fide hard science. Charles Bennett has been a leader in moving Shannon's ideas in the classical realm to the exotic world of quantum theory.

Landauer made a number of key observations:

  1. Information is physical
  2. Information is independent of its physical embodiment
  3. Erasing one bit of information dissipates at least kT/2 of energy

The first point indicates that without mass or energy, there is no information. How much mass is there in information? The old joke is that "my briefcase is so heavy because I downloaded so many books onto my hard drive." This confuses two types of information--the message or meaning that is conveyed vs the basic binary bits underlying that information. A 80GB hard drive contains the same number of bits no matter what is downloaded. They just aren't all intelligible until we rearrange them.

The second point is easily visualized by thinking of a telephone conversation. As the information passes from the mind of person A to the mind of person B, the physical medium that conveys the information changes many times. The information doesn't.

Randy

------------------------------------------------------------------------------
Don't get soaked. Take a quick peek at the forecast
with theYahoo! Search weather shortcut.

To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Mon Apr 9 22:40:08 2007

This archive was generated by hypermail 2.1.8 : Mon Apr 09 2007 - 22:40:08 EDT