In the weaker sense, informational connections between events or variables involve no more than ordinary correlations (or perhaps correlations that are "non-accidental" in some physical sense involving causation or natural laws). This sense of information is associated with Claude Shannon (1948), who showed how the concept of information could be used to quantify facts about contingency and correlation in a useful way, initially for communication technology. For Shannon, anything is a source of information if it has a number of alternative states that might be realized on a particular occasion. And any other variable carries information about the source if its state is correlated with that of the source. This is a matter of degree; a signal carries more information about a source if its state is a better predictor of the source, less information if it is a worse predictor.
Godfrey-Smith also pointed out, as have many ID critics before him, how Dembski and other "ID proponents of "Intelligent Design" creationism appeal to information theory to make their arguments look more rigorous." For instance Dembski likes to use the term information, rather than probability because the former can appeal to Information theory even though all he does is apply a transformation to a probabilityThis way of thinking about contingency and correlation has turned out to be useful in many areas outside of the original technological applications that Shannon had in mind, and genetics is one example. There are interesting questions that can be asked about this sense of information (Dretske 1981), but the initially important point is that when a biologist introduces information in this sense to a description of gene action or other processes, she is not introducing some new and special kind of relation or property. She is just adopting a particular quantitative framework for describing ordinary correlations or causal connections. Consequently, philosophical discussions have sometimes set the issue up by saying that there is one kind of "information" appealed to in biology, Shannon's kind, that is unproblematic and does not require much philosophical attention. The term "causal" information is sometimes used to refer to this kind, though this term is not ideal. Whatever it is called, this kind of information exists whenever there is ordinary contingency and correlation. So we can say that genes contain information about the proteins they make, and also that genes contain information about the whole-organism phenotype. But when we say that, we are saying no more than what we are saying when we say that there is an informational connection between smoke and fire, or between tree rings and a tree's age
That's the full extent of ID's appeal to information theory, take the negative base 2 logarithm of a probability.To assign a measure of information to the event, you just mathematically transform its probability. You find the logarithm to the base 2 of that probability, and take the negative of that logarithm. A probability of 1/4 becomes 2 bits of information, as the logarithm to the base 2 of 1/4 is -2. A probability of 1/32 becomes 5 bits of information, and so on. In saying these things, we are doing no more than applying a mathematical transformation to the probabilities. Because the term "information" is now being used, it might seem that we have done something important. But we have just re-scaled the probabilities that we already had.
So what about some of the other terms used by ID proponents such as complexity? Surely that means something?Despite all the detail that Dembski gives in describing information theory, information is not making any essential contribution to his argument. What is doing the work is just the idea of objective probability. We have objective probabilities associated with events or states of affairs, and we are re-expressing these probabilities with a mathematical transformation.
Again we find that ID's usage of terminology adds nothing and only leads its followers into confusion as they have come to believe that these terms mean something else. In other words, Complex Specified Information CSI all boils down to the followingSo far I have discussed Dembski's use of the term "information." Something should be said also about "complexity" and "specification," as Dembski claims that the problem for Darwinism is found in cases of "complex specified information" (CSI). Do these concepts add anything important to Dembski's argument? "Complexity" as used by Dembski does not add anything, as by "complex information" Dembski just means "lots of information."
Or in other wordsThat completes the outline of Dembski's information-theoretic framework. Dembski goes on to claim that life contains CSI – complex specified information. This looks like an interesting and theoretically rich property, but in fact it is nothing special. Dembski's use of the term "information" should not be taken to suggest that meaning or representation is involved. His use of the term "complex" should not be taken to suggest that things with CSI must be complex in either the everyday sense of the term or a biologist's sense. Anything which is unlikely to have arisen by chance (in a sense which does not involve hindsight) contains CSI, as Dembski has defined it.
Back to the age old creationist argument of improbability. Richard Wein, Mark Perakh, Wesley Elsberry and many others have shown how Dembski's 'novel' approach is neither novel nor particularly relevant as we lack sufficient resources to calculate the probabilities involved. In other words, the reason why ID is scientifically vacuous is because all it can contribute is a calculation of the negative base 2 logarithm of a probability and it cannot calculate said probability.So, Dembski's use of information theory provides a roundabout way of talking about probability.
103 Comments
Ryan · 2 January 2008
I've been hammering the creationist argument about information a lot. It gets brought up over and over, and the never seem to acknowledge that people have addressed their concern before.
Check out the blog:
http://aigbusted.blogspot.com
-Ryan
Tex · 3 January 2008
Joe Felsenstein · 3 January 2008
I think I have a different perspective. Specified information, which was defined originally by Leslie Orgel (as William Dembski himself says) is perfectly meaningful once we agree on what scale to rank individuals (and the relevant one is fitness). Dembski's critics point to his vagueness about what the scale is -- but defining it as fitness is the way to rescue that part of his argument. The rest of his argument, that deterministic and random functions can't create it, is where he is wrong, as I explain in my article in the current issue of Reports of the NCSE (the issue that isn't quite up on their web page yet).
The idea that random stuff has lots of information is mistaken. It has lots of things that need explaining but that is different from saying that it has a lot of specified information. It has none. If I ask you for some good hot tips on the coming horse races, and you say sure and send me random numbers, I ought to be royally ticked off, and should not congratulate you on sending me so much information. Because what you sent me does not help me at all.
Popper's Ghost · 3 January 2008
JuliaL · 3 January 2008
Jeffrey Shallit · 3 January 2008
Joe, the whole concept of "specified information" is nonsense. A 'specification' means the object conforms to a pattern, i.e., is easy to describe. But 'information' in the sense it is understood by mathematicians and computer scientists measures to what extent an object is hard to describe; that it, how much it does not conform to a pattern.
I recommend reading Kolmogorov complexity and its applications by my colleagues Li and Vitanyi, or my long paper with Elsberry debunking the notion of 'specified complexity'.
fnxtr · 3 January 2008
Semantic content. I think that's in a way what WAD is trying to say, that life has meaning. But that's a philosophical argument, and he's trying to make it sound scientific by calling it 'information' instead of 'meaning'... or 'intent'... or 'purpose'...or 'design'. Circular and pointless.
snex · 3 January 2008
Paul Burnett · 3 January 2008
The Stanford Encyclopedia of Philosophy also has an article on "Creationism," which contains the following statement in its conclusion:
"Scientifically Creationism is worthless, philosophically it is confused, and theologically it is blinkered beyond repair. The same is true of its offspring, Intelligent Design Theory."
mark · 3 January 2008
I forget--how did Dembski claim to specify information? It is so easy to look at some thing, and see a pattern in it. How much complex specified information can I detect in an ink blot, or in clouds? I can see patterns in biology, some that require a lot of words to describe, but many are easily explained by common descent or contingency.
Stanton · 3 January 2008
Pete Dunkelberg · 3 January 2008
Ye Filter.
Merlin Perkins · 3 January 2008
Dembski's No Free Lunch explains csi in a way that I could eventually understand. It was quite convincing and I think most of you have missed it.
On an unrelated issue: Dawkin's could not give an example of a mutation that increased information (by any definition). Is there an example of a mutation that improves the function of an enzyme or makes a new structure or is evolution in a positive direction?
Merlin
RBH · 3 January 2008
Stanton · 3 January 2008
RBH · 3 January 2008
Popper's Ghost · 3 January 2008
Popper's Ghost · 3 January 2008
Popper's Ghost · 3 January 2008
PD · 3 January 2008
PG nails it.
* NO SEMANTIC CONTENT IN INFORMATION THEORY
* INFORMATION THEORY IS USELESS TO ID and
everything else he said on this too.
Surprisingly there are even a couple
articles on one of the IDist websites
saying the same thing. It makes me think
the author was trying to get through to
someone. It obviously did'nt work but
that's what happens when people have
concrete in their heads.
Muldoon · 3 January 2008
I have not been impressed with Dembski's work with regards to CSI. Behe's idea about IC seems more a plausible angle, if it could be positively demonstrated that there is no chemical pathways to certain structures. I ask the crowd here for your thoughts: if design is present in nature, is there any way to detect it, excepting for blatant messages to us in the DNA?
Raging Bee · 3 January 2008
Muldoon: You'd have to give us an exact definition fo "design" before anyone could objectively verify whether or not it is "detected" in nature. "It looks designed (to me), therefore it is designed" doesn't cut it, especially for an artsy type like me who sees "design" of sorts in ice crystals.
Mike Elzinga · 3 January 2008
Some of the confusion and difficulties associated with attempting to apply information theory to biology can be illustrated with a simple analogy to dendritic growth (e.g., icicles, stalactites, or other mineral or neuronal growth). Initially, before a specified branch of a dendrite has developed, the probability of its development would appear to be very low. However, this misconception arises because the branch is specified, and it ignores the contingencies that could just as easily have produced others.
In reality, millions of possibilities are available before a particular branch develops, and once a branch starts (because of contingencies existing in the system or its environment), the probabilities of its continuation may be quite large. This is just another way of saying that the probability of reaching certain states is dependent on what nearby states are available. Singling out a particular branch and asserting that its probability is low relative to the background states from which it developed (and therefore special in some way) is misleading because millions of other branches could just as easily have developed.
It may be meaningful in some way to calculate the probability (or, equivalently, the entropy or “information”) of that particular branch relative to nearby states, but that doesn’t take into account the millions of other branches that could have but didn’t develop. Given the right conditions and energy throughput, dendritic growth may be inevitable for a given system; it’s just the particular configuration that appears improbable if one ignores the broader picture.
Similarly, singling out particular features of an organism and suggesting that they are improbable (and therefore must be designed) ignores the record of evolutionary history. The fact that there are so many varied life forms that exist, and have existed, suggests that a large number of life forms are possible within the energy ranges and conditions on this planet. Just because other forms didn’t develop doesn’t mean that, given suitable contingencies, they couldn’t have developed. The variety of life on this planet appears to be in a constant state of flux. And the evolutionary tree does appear to be much like constantly changing dendritic growth. Species and their characteristics arise against a background of contingencies, and once they are established and selected, they form a template for further development along a particular branch (at least temporarily until further contingencies wipe out the branch).
When Dembski asserts something is improbable (and hides this assertion in a negative logarithm to base 2), he is arrogantly assuming he knows specifically how the current state of an organism was achieved and that there were no alternative organisms that could have developed. It’s like he gets dealt a 52-card hand from a shuffled deck of cards and concludes that the amount of information contained in his hand is minus log2(1/52!).
JGB · 3 January 2008
I think some of your terminology is muddled muldoon however I think your question if I am interpreting it correctly has some merit. The problem lies in proving their are no viable mutation pathways from point A to point B. This is not impossible just incredibly difficult to do in a truly rigorous sense. You have to account for an impractical amount of possible contingencies if your initial set of conditions fail to be viable as well as the wide variety of possible pathways. On the other hand in cases where researchers have tried to fill in potential intermediates they have found a fair amount of success suggesting that in practice we will find molecular intermediates given a reasonable amount of time and resources for a wide variety of systems. It gets much dicer if you want to talk about any gene because many of them are not nearly as well suited to experimental characterization.
Popper's Ghost · 3 January 2008
Henry J · 3 January 2008
Popper's Ghost · 3 January 2008
Shebardigan · 3 January 2008
And all this time I'd been saddled with the impression that the word "specified" within the expression "CSI" had been put in there by the usual suspects in order to indirectly introduce the concept of a "designer" at the ground floor of the whole gallimaufry.
After all, something can't be "specified" unless some specifier has engaged in specifying. The CSI in the bacterial genome that produces a flagellum is clearly exactly equal, functionally, to a CNC tape for a milling machine or a set of cards for a Jacquard loom. Both of those are complex, informative, and would have been specified by some engineer or designer.
Tex · 3 January 2008
Henry J.
I’d think that to be relevant, the information has to be at least somewhat persistent. Positions of molecules in a vapor change constantly, so there’s no persistence there.
This does not argue against my point that there is a wealth of information there, no matter how useful you may find it.
If, however, you insist on persistance, then just change my analogy to a pile of 1000 bricks stacked in a 10 X 10 X 10 array versus the same number of bricks randomly scattered over a lawn where they will persist in this arrangement until serious effort is expended to move them.
Popper's Ghost · 3 January 2008
Joe Felsenstein · 4 January 2008
Jeffrey Shallit · 4 January 2008
Joe, the term "information" has precise meaning for mathematicians and computer scientists under the rubric of Shannon or Kolmogorov information. If you want to call the "Whatchamacallit" in the genome "information", you are going to confuse the rest of us who already have a different definition, established for many years, in mind. Why not give it a another name entirely?
Shebardigan · 4 January 2008
Mike Elzinga · 4 January 2008
Joe Felsenstein · 4 January 2008
Eric Finn · 4 January 2008
Carl Bergstrom · 4 January 2008
Joe Felsenstein · 4 January 2008
Thanks, Carl. That ought to do a good job of covering up the fact that I am an ignoramus. Check's in the mail.
Popper's Ghost · 4 January 2008
Popper's Ghost · 4 January 2008
Popper's Ghost · 4 January 2008
Henry J · 4 January 2008
Popper's Ghost · 4 January 2008
Popper's Ghost · 4 January 2008
Popper's Ghost · 4 January 2008
Popper's Ghost · 4 January 2008
Eric Finn · 5 January 2008
Popper's Ghost · 5 January 2008
Jeffrey Shallit · 5 January 2008
Joe:
You say "It’s going to be hard to find a different one, because “information” is also a word used in colloquial English as well as in the languages of Mathematics and of Computer Science. "
Sorry, I find this objection silly. The words "field" and "group" also have meanings in colloquial English, but if you talk about "elements in a group" or "field extensions", no one is going to think you are talking about their colloquial meanings.
If you want to give a mathematical definition of information that differs from the standard, call it something else.
Carl Bergstrom:
Dembski's "specified information" is completely bogus. Read my long paper with Elsberry.
Eric Finn · 5 January 2008
Torbjörn Larsson, OM · 5 January 2008
Thanks PvM, that was an interesting article.
If I may review it from my admittedly dim understanding (not using any of the two common information theories in my work), Godfrey-Smith has extensively covered "information" as used in biology. He is correctly noting the obvious problem of accepting Shannon's description of a physical observable, yet speculate in formulations that mistakes information for a physical object.
This philosophical description is however not how a scientist would have described a scientific area. We have two different models of information (Shannon theory and algorithmic information theory) that would need to be covered. Godfrey-Smith doesn't mention the later, even when discussing coding issues. Those two models have already limited applications in physics, which would warrant a description in such a review, and it would be surprising if biology would find information a better tool.
Finally, I think Godfrey-Smith may have less of a grip on signal theory. In its purest form signal theory isn't about what information (correlations) a signal codes of a source system, but how to detect and decode a predetermined signal among noise. This can even be done in a model-less fashion.
Source system identification (modelling), whether as a black box or as a physically informed model, is the domain of systems and control theory. I think that may be a point of the Developmental Systems Theory Godfrey-Smith mentions, but you wouldn't recognize it from his description. I have no idea of how successful systems identification can be of biological systems, with their likely distributed, changing (during growth, repair, sickness, et cetera), and contingent components. It is hard enough to reverse-engineer when you have systems with reasonably static and localizable but unobservable internal nodes, say IC circuits.
I think the later type of review would have prepared the reader for an informed discussion along the lines of Shallitt, Elzinga and PG. Each has obviously done some thinking about the applicability of information in biology, and I'm enjoyed about the opportunity to learn more.
Torbjörn Larsson, OM · 5 January 2008
Torbjörn Larsson, OM · 5 January 2008
Torbjörn Larsson, OM · 5 January 2008
Merlin · 5 January 2008
Does motivation of the questioner somehow make the question not legitimate?
Dawkins did not answer the question because he could not. And when he tried, he answered a different question. Various of you have at least tried to answer my question. Good.
Intuitively, (what one relies on when one is ignorant), one knows specification when he see it. (Wasn't it Dawkins who acknowledged this when he told his students that what they were seeing is only the appearance of design?) And intuitively one know what information is, and intuitively, YOU know that you cannot make random changes to any highly complex, functioning system and expect improvement. Would you go into an automated factory, make a few random changes and go to the shipping dock to await the new products? If you do, take a book. You'll be there a while.
Now, why should I doubt my intuition? If there were good examples of where it was wrong, I would begin to doubt. (The lactase example was not convincing. The Milano one was better.) Or if there were a good model of how NS could weed out all the bad mutations and keep the ones that increased information/improved function/created new structures, then you might be on to something. But along with what might be improved function/increased information there is clearly a lot of the opposite. Five thousand plus know genetic diseases? Wouldn't any increased information/improved function be swamped by the garbage?
Merlin
Joe Felsenstein · 5 January 2008
Mike Elzinga · 5 January 2008
Popper's Ghost · 5 January 2008
Popper's Ghost · 5 January 2008
Popper's Ghost · 5 January 2008
PvM · 5 January 2008
Mike Elzinga · 5 January 2008
If all one is trying to do with the idea of “information” is to make some quantitative assessment about survivability or fitness in a given environment, then I don’t see anything that is either profound or necessary in the idea, or that isn’t already available in other, more obvious kinds of calculation such as simple probability or change-of-entropy calculations.
Physical systems are full of examples in which improbable states are more easily reached by way of nearby states (crystal growth, catalysis and catalytic substrates, optical pumping, bootstrap processes, pressure changes, temperature changes, etc.). It is then possible, at least in principle, to calculate the probabilities of reaching and surviving in various nearby states from the current state (where the current state itself may be a result of the system’s history). Presumably, if one could nail down the probabilities of reaching successive stages in an evolving biological system, one could model theoretical evolutionary systems far out into their future by bootstrapping off successive states of development
But one can’t go back too far in the history of the system in order to do such a calculation on a late state because earlier states may not lead to many (or any) of the later states. That has to be a matter of system history. I think Torbjörn’s quote of Dawkins (comment #139317) is another way of stating these ideas in the case of gene pools.
Popper's Ghost · 5 January 2008
BTW, they themselves slip into the language of my alternative definition, e.g., "the fitness value of an informative cue". Of course "informative" is redundant; a cue is "informative" precisely to the degree that it has value (as defined).
Popper's Ghost · 5 January 2008
Popper's Ghost · 5 January 2008
P.S. how do you define a horse race? Perhaps you meant "specification of what we care about" ... how do you specify it, in a way that "works"?
Popper's Ghost · 5 January 2008
Popper's Ghost · 5 January 2008
Popper's Ghost · 5 January 2008
Mike Elzinga · 6 January 2008
Mike Elzinga · 6 January 2008
PvM · 6 January 2008
Mike Elzinga · 6 January 2008
Popper's Ghost · 6 January 2008
Popper's Ghost · 6 January 2008
Popper's Ghost · 6 January 2008
Hmmm ... actually, while the talkorigins page I linked to attributes the statement to (Adami et al. 2000), nothing of the sort appears in that paper.
Toni Petrina · 6 January 2008
It is also interesting to notice that Dembski equivocates between specification and function. Other error is that he calculates complexity with regards to uniform complexity and from scratch, ignoring natural contingency of biological systems.
Thus, it is trivial to show that when we discovered that HIV evolved VPU unit (thanks to Abbie Smith), HIV virus is CSI. I is complex (because Dembski ignores previous steps), it has a function so it is specified thus HIV with VPU (HIV-1?) is CSI and it is obviously designed. By definition.
Thus CSI fails because if you refuse to model according to evolutionary models (all organisms are descending one from another, so are their gene pools) you can make everything as CSI. In other words, all mutations that change function are designed mutations.
Toni Petrina · 6 January 2008
Err, instead of "with regards to uniform complexity" it should be "with regards to uniform probability". Also, "It[HIV] is complex" not I :o
PvM · 6 January 2008
ndt · 7 January 2008
Joe Felsenstein · 7 January 2008
PvM · 7 January 2008
Shebardigan · 7 January 2008
Torbjörn Larsson, OM · 7 January 2008
Thanks all, but particularly to Mike Elzinga and PG, for enlightening examples of contingencies in evolutionary history as pertaining to Dawkins et al descriptions of information in variation and selection.
Torbjörn Larsson, OM · 7 January 2008
Popper's Ghost · 8 January 2008
Popper's Ghost · 8 January 2008
Popper's Ghost · 8 January 2008
PvM · 8 January 2008
Merlin · 8 January 2008
Joe Felsenstein
A quick search gave me Kimura's neutral theory of mutation. Is that the one? It seems to me that it all depends on the ratios of deleterious, neutral and beneficial mutations. I have heard estimate of one out of 100, 1 out of 1000, and fewer beneficial mutations to all others. What are the current estimates?
Of course, deleterious mutations TEND to get weeded out, and the worst are weeded out the best, but with new ones arising continually and beneficial one rare, the net effect would seem to be negative. Could this be resolved by a computer model?
There is still the problem of getting new structures/new functions by mutations.
On some creationist or ID website, I read a discussion of an article claiming that the accumulation of "neutral" mutations had a negative effect. If I see it again I'll let you know.
PvM and Popper's Ghost
"Specification is simple: it's called function in biology"
Yes, however, the thing commonly specified is a polypeptide sometimes thousands of amino acids long that has to fold in a certain way. Lots of room for error. Not much for improvement. (Sex spreads the errors) Are rates of genetic diseases decreasing? Have they been decreasing throughout the existence of humans?
Torbjorn Larsson
Beneficial and a trivial increases in information, perhaps. And you may be correct on everything else if you assume the evolution that I am questioning. We observe genetic diseases. Where are the new structures/new functions?
....
Demski, using work by Douglas Axe, describes small islands of functioning genes surrounded by a vast ocean of non-functioning possible sequences of amino acids. The implication being that you cannot get from one function to another by descent with modification. Is this a fair picture?
Mike Elzinga · 8 January 2008
Popper's Ghost · 8 January 2008
Popper's Ghost · 8 January 2008
Popper's Ghost · 8 January 2008
Joe Felsenstein · 8 January 2008
Torbjörn Larsson, OM · 8 January 2008
Torbjörn Larsson, OM · 8 January 2008
Joe Felsenstein · 9 January 2008
Merlin · 10 January 2008
Torbjorn Larsson and Joe Felsenstein
I will try to get thru the materials you have referenced. Time and the math may be a problem. Thanks. I can see that I am not well enough informed to discuss this with you. None the less, the problem is getting new information/structures/function, by whatever definition. I understand that one can design a good radio antenna using a evolutionary algorithm, but one will never happen upon a bicycle wheel using the same algorithm.
Mike Elzinga
The fossil record shows little change, once a species shows up. Isn't this why the theory of punctuated equilibrium was proposed; to explain the stasis?
Popper's Ghost
Dembski, of course. Thanks, my mistake, and I should have said amino acids when I said genes. It is in No Free Lunch. For a functioning enzyme that has 1000 amino acids, there are 20 to the 1000th possible sequences of that same length. Sequences that vary slightly from the functioning one, will perform the same function, but as more changes are made, function drops off and ceases but the number of the remaining possible sequences is so huge that it is impossible to get to another functioning sequence by chance.
GuyeFaux · 10 January 2008
Stanton · 10 January 2008
Glen Davidson · 10 January 2008
Joe Felsenstein · 10 January 2008
Mike Elzinga · 10 January 2008