Natural and unnatural information

(Copied from a previous blog and updated).

This post is in response to a discussion on UD about whether DNA is a code and contains information. It is mostly well-worn territory but maybe there is something slightly different and what I have to say is too long for a comment so I put it here.

In this comment Jerry wrote:
This discussion has appeared several time in the last few weeks and the anti ID people think they have scored points by asking for a definition of information when the simplest definition from a dictionary will suffice.

This makes a point which runs through much of the discussion. Words such as “information”, “symbol”, “code” and “meaning” are bandied about as though their use was obvious and unambiguous. In fact the ordinary English usage of these words varies greatly according to the context. And it is no help defining one of these in terms of one of the others (for example, information is data that means something, a symbol is a sign with meaning, a code is a set of symbols) – that just shifts the ambiguity. I don’t say that DNA is not a code – I just want to pin down what “code” means in this context.

In particular a vital distinction is between natural and non-natural “meaning” (and therefore “information”, “symbol” and “code”). For a full explanation read P.H. Grice’s seminal paper on meaning. Briefly he points out that sometimes an event or object (A) means some other event or object (B) because their is a causal relationship "clouds mean rain". This is natural meaning. On other occasions an an event or object (C) means some other event or object (D) because we recognise the intention of the person who created C. Often, but not always, C takes advantage of a prior convention. Grice uses this example:

Compare the following two cases:
(1) I show Mr. X a photograph of Mr. Y displaying undue familiarity to Mrs. X.

(2) I draw a picture of Mr. Y behaving in this manner and show it to Mr. X.

Case 1 contains information because there is a well-defined causal chain from the impropriety to the sign. Case 2 only gives information if the recipient makes some assumptions about why I drew the picture.

 

I can illustrate this with Jerry’s attempt to tell us the meaning of “information”. He says the simplest definition from the dictionary will suffice. OK let’s try to pin down this simplest definition.

The link he kindly provides offers five different quick definitions.

1 (communication theory) a numerical measure of the uncertainty of an outcome
2 knowledge acquired through study or experience or instruction
3 a message received and understood
4 formal accusation of a crime
5 a collection of facts from which conclusions may be drawn
He also offers:
6 data that mean something
7 such things as news; intelligence; words; facts; data; learning; lore

There certainly seems to be a lot of definitions to choose from. But some can be eliminated either because they are not simple or because they cannot apply to DNA:

1 is close to how many ID people define information but it is certainly not simple. So I guess that is out.

2 requires study or experience. I am assuming you believe that DNA would contain its information even if no one studied it or even knew of it. So this is out.

3 requires someone to understand the message – so again I don’t think you can mean this for similar reasons to 2.

4 is specific to crime.

5 appears to be included in 7 – which also includes “data” in its list. It adds the requirement that it should be possible to draw a conclusion – but you can do that from all the items in 7.

6 defines “information” in terms of one of the other ambiguous terms: “meaning”. So it requires a description of the use of the word “means” in this context before it is useful

So the most useful definition appears to be the ostensive definition:

7 such things as news; intelligence; words; facts; data; learning; lore

A few striking things about this list.

1) They are man-made
2) The physical medium is not what defines them. News is the same news whether it be in print, on the radio or over the internet.
3) They are all instances of what Grice calls non-natural meaning. They allow us to know more about the world but only because we recognise the intention behind them. The news on TV is only news if you understand that the programme is intended to convey what is happening in the world – otherwise it could equally be a work of fiction or even just a set of abstract images.

So is Jerry saying that DNA has non-natural meaning? That it relies on us recognising the intention behind whoever or whatever created it? Somehow I doubt it. And I am still struggling for that definition of information