Re: Where does information come from?

On Fri, 02 Jun 2006 22:15:33 +1000, John Wilkins <john@xxxxxxxxxxxxx>
wrote:

r norman wrote:
On Thu, 01 Jun 2006 13:03:15 +1000, John Wilkins <john@xxxxxxxxxxxxx>
wrote:

Friar Broccoli wrote:
John Wilkins wrote:

Absolutely right. It comes only from intelligence.
This thread is growing so fast, that I will probably never be
able to read to the end, so I just gave up and decided to ask
you a question, hoping it has not been answered elsewhere.

If I see a spider with an hour glass shape on it I know it is a
black widow and quickly move my hand away.

If I am interpreting your statement correctly, something I am
not sure of, then the information is in me, not in the spiders
hour glass, and that is why I moved my hand.

Similarly, if a monkey in a tree, sees a leopard, then he also
has information, which allows him to escape.

Similarly if a frog (or dinosaur) sees a butterfly with
particular markings, it knows it to be poisonous and refrains
from eating it. Does the frog have the same type of information
that I do?

Next down, if a bumble bee sees a wasp with a certain coloration
approaching, it "knows" it is a predator that will inject it
with eggs, and so quickly leaves the premises. Does the bumble
bee have information?

If yes, the next step down is a sunflower, which sees the sun
and turns toward it. Does it turn because it has information?

Finally, embarrassingly, I do not know enough cell biology to
provide a single concrete example, but generally in a hand
waving kind of way, when I my cell community (my body) is
attacked by viruses, many cells in my body receive signals
telling them to transcribe special proteins of one sort or
another from the instructions contained in the DNA. You say
these instructions are not information.


So, I'm not sure where in the little ladder I have just
constructed, reactions go from being information to just
reactions (or whatever). Could you tell me where the break
occurs and why the event above is information, while the event
below is not?
First of all this sense of "information" is sometimes called Dretske
information after the philosopher who proposed it was the most useful meaning
in cognitive philosophy. I think of it as "signalling information". It
requires a functional neural system to process the stimuli, and so if the
organism lacks a nervous system or close analogue (I think phototaxis in
plants is insufficient), it ain't a signal.

Moreover, I would restrict (as I have in the paper I sent you) signalling
information to facultatively learning neural systems. If the organism does not
learn the "meaning" of the signal, then it is no different to any other causal
chain, such as the one that causes the sunflower to turn. It's just a
propensity to respond to external conditions in a reliable manner. As such
that, too, doesn't deserve the label "information".

Signalling, or Dretske*, information is learned correlations between
observation or stimulus and some fact in the world.

Now this is nothing at all like "genetic information". It is somewhat like
cell-cell signalling (for at least one obvious reason - a neural system is a
cell-cell signalling system), except that the propensities to signal are
obligate (can't be modified or occasional). So it is of a different class IMO.

DNA transcription is a simple chemical reaction mediated by structures in the
cell. Unless *every* chemical reaction is "information transfer", the
expression of DNA carries no information, only causal regularities.

*Dretske is a bit more restrictive here - he requires that the signalling is
100% reliable. I do not.

Detske information seems to be quite similar to the signaling
information I proposed. Of course it need not be 100% reliable,
nothing is. That is why I described it in terms of probability
distributions (the Shannon method, although it is not necessary to use
Shannon's specific metric). If receipt of some stimulus causes you to
change the probability distribution of your behavior, then that
stimulus carried some information.

Yes. I can live with this.

Genetic information can be put into this model -- the behavior is the
construction of a structure. In this sense, the genome is like the
blueprints for a house or the circuit diagram for an electronic device
-- when interpreted by an appropriate system, it results in the
production of a specific structure (more or less -- again the
description need not be 100% reliable or precise or followed in
complete detail). I happen to think that this is the only reasonable
interpretation of what biological 'information' might be.

I disagree. If you say that this is genetic information, you must also by
parity of reasoning suppose environmental normal conditions also to be
information, along with the entire suite of biological structures that stop
DNA from just being a white stringy substance that does nothing by slowly
denature.

The genome is not a set of blueprints or programs. DNA is a molecule that
catalyses other molecules in ways and at times that are determined by yet
other molecules as well as other parts of itself under conditions that are
normal for the organism. We can, if we safely ignore a range of complexities
and exceptions, *describe* the developmental sequence as a "program" but all
that does is tell the hearer what we happen to think is interesting about the
developmental processes. In fact, it does a range of things that are very much
unlike a program. For a start, much of the causal process is determined by
polarities in the cells, by the density and type of neighbouring cells, and by
the prior history of the cell in which the DNA is expressed, regulated or edited.

I think that the "blueprint" metaphor is almost 100% *not* what DNA is best
described as.

Of course, the fact that I am a physiologist particularly interested
in signaling and systems theory has no bearing whatsoever on the fact
that such a signaling model is the only reasonable one!

Of course. For the same reason, the fact that I am an extreme nominalist has
no bearing at all on my rejection wherever possible of abstract entities in
biology :-)

And plants most definitely respond to signals in the environment
including the position of the sun. If bugs that fly into the light
process information, than so do plants that grow towards the sun. In
fact, the part of the plant that detects the light is separate from
the part that responds to produce a change in shape of the stem. So
information is present in the photic stimulus needed to detect the
direction and that information is signaled from the receptor to the
effector. By the same token, magnetotactic bacteria use information
about the direction of the magnetic field to 'seek' deep water that
tends to be anoxic, their 'preferred' habitat. When you think in
terms of detector -> message channel -> effector, it is hard to put
plants and protists and prokaryotes into completely different
categories from animals. We all respond appropriately to
informational cues in the environment.

It's a big step from "phototaxis or magnetotaxis occurs reliably according to
physical causal processes" to "we all respond to informational cues". In fact,
it's wholly question begging, since this is exactly what is at issue.

You and *I* (and a few other organisms with facultative behaviours mediated by
learning systems) respond to information on my account. But a plant no more
processes information by turning to the sun than a bimetallic thermostat
processes information by curving in the heat.

Dretske may have intimated (or insisted, or you may have) that the
correlation between stimulus and response is learned but evolution can
also generate such a correlation. And the fact that genetic
'information' merely produces specific chemical reactions is no
impediment to the informational notion. When reduced to cellular
mechanisms, everything we do is reduced to specific biochemical and
biochemical reactions -- molecules reacting chemically or changing
size or shape or moving one with respect to another. That is about
all that any biological system can due, when you come down to it. The
"higher order" system (yes, I mean emergent properties) behave in
interesting ways, but at heart it is only biochemistry/biophysics.

Yes indeed. So why call it anything more than physical behaviours unless we
are applying informational language to the paradigm cases for which
informational talk was devised (i.e., learning systems guiding behaviour)?

It's very much like (and related to) the use of teleological language in
biology. It is one thing to say that an organism acts to achieve a goal when
it can visualise that goal and reason. It's a whole other matter to say a tree
acts teleologically in producing seed. The language is warped and the
reasoning processes are misled, sometimes dramatically. Information is the new
teleology.

We certainly are in agreement about mechanisms and physical behaviors.
Where we strongly disagree (and have for some time) is your obstinate
and inexplicable refusal to recognize 'emergent' properties, which is
exactly what 'information' is. The teleology you rightly describe is
simply the 'function' or the 'role' that some system or process plays
when it is considered as part of a larger complex system. That
'function' or 'role' is also completely described in mechanistic
terms, the working out of the components that the system or process
contains as elements, and how those components interact. The
mechanism involves drilling down levels of organization, it is
analytic and mechanistic. The teleology involves integrating up the
levels of organization, it is synthetic and holistic. They are
complementary ways of looking at the world.

The classical example of a regulatory system is the thermostatic
control of temperature in a house.The thermostat contains a
temperature measuring device, a "set point" and the ability to compute
whether the current temperature is above or below the set point. The
thermostat sends a signal to an effector structure, a furnace or air
conditioner that uses the information in the signal to change its
behavior in a way appropriate to deal with the situation detected by
the thermostat -- either add heat to the room to increase the
temperature in case it is below the set point or add 'cold' to the
room to decrease it in the opposite case. It is easily understood as
a negative feedback regulatory system (a homeostatic system in
physiological terminology) which involves both signaling, the
transmission of information from sense organ to effector organ, and
computation, the determination of whether the room is too warm or too
cold. At the same time, all that happens is that the two sides of a
bimetallic strip expand and contract differently in response to
temperature changes and consequently cause variable curvature.
Electrical contacts move when the curvature of the strip changes
causing them to touch or to separate. Electric circuits are either
closed, allowing the flow of current, or open, preventing the flow.
Motors (probably through intermediary relays) are activated by current
flow, etc. etc. Every detail is simply a physical process working
out. Still, the *system* as a whole processes information.

If you examined your " paradigm cases for which informational talk was
devised (i.e., learning systems guiding behaviour)" you will find
nothing more than chemicals reacting or molecules changing shape or
moving past one another. That is all that the components that make up
cells that make up brains that are responsible for learning and
behavior can do. Viewed in this light, everything is simply physical
behavior. That is the reductionistic, mechanistic, analytic view of
the world. However when you look at the molecules as part of a cell,
and the cell as part of a neural network, and the neural network part
of an organism with a history and experience, then you can see
'learning' and 'behavior' and 'information'. I say that the plant
responding to light and the molecular processes underlying protein
synthesis are exactly the same. From one perspective they are simply
physical processes. From another, they are part of a larger pattern
in which you can truly and usefully apply the concepts of information
processing.

As a separate and very minor issue, I agree that the "blueprint"
metaphor for DNA is terribly flawed. I was searching for some
description of how to specify structure and that was the bad example
that came to mind. DNA is more like the scrap book of some chef
thinking about writing a cook book someday. It contains recipes for
everything from appetizer to dessert, for formal dinners and quick
snacks. It contains snips and fragments of recipes. It contains bad
recipes that should be discarded and multiple copies of recipes with
terrible mistakes. It contains all the doodling and sketching and
idle scribbling that the chef might every have written. And it dumps
all those things together into a big pile with no index or table of
contents or commentary. Still, it contains 'information' when viewed
properly. That 'information content' depends critically on the
experience and judgement and discernment of the molecular biological
system that transcribes and translates it.



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Relevant Pages

  • Re: Where does information come from?
    ... Finally, embarrassingly, I do not know enough cell biology to ... I think of it as "signalling information". ... DNA transcription is a simple chemical reaction mediated by structures in the ... other molecules as well as other parts of itself under conditions that are ...
    (talk.origins)
  • Re: Where does information come from?
    ... Finally, embarrassingly, I do not know enough cell biology to ... I would restrict signalling information to facultatively learning neural systems. ... DNA transcription is a simple chemical reaction mediated by structures in the cell. ... DNA is a molecule that catalyses other molecules in ways and at times that are determined by yet other molecules as well as other parts of itself under conditions that are normal for the organism. ...
    (talk.origins)
  • Re: Where does information come from?
    ... Finally, embarrassingly, I do not know enough cell biology to ... I think of it as "signalling information". ... DNA transcription is a simple chemical reaction mediated by structures in the ... other molecules as well as other parts of itself under conditions that are ...
    (talk.origins)
  • Re: Where does information come from?
    ... Finally, embarrassingly, I do not know enough cell biology to ... It requires a functional neural system to process the stimuli, and so if the organism lacks a nervous system or close analogue, it ain't a signal. ... I would restrict signalling information to facultatively learning neural systems. ... Unless *every* chemical reaction is "information transfer", the expression of DNA carries no information, only causal regularities. ...
    (talk.origins)
  • Re: Chemical bonding inside living vs non-living things
    ... The atoms are the same, the molecules, however, are not. ... The cell cycle is well understood. ... and how a differentiated multicellular organism develops. ...
    (sci.chem)