Dembski’s CSI

(5th April, 2013: stickying this, for a bit, as it has come up.  Mung might like to comment).

Time to look at this in detail, I think 🙂

His definitive paper to date on CSI, is Specification: The Pattern That
Signifies Intelligence.
It is very clearly written, not very mathy, but, by the same token, a paper in which it is easy (IMO) to see where he goes wrong.

Here is the abstract:

ABSTRACT: Specification denotes the type of pattern that highly improbable events must exhibit before one is entitled to attribute them to intelligence. This paper analyzes the concept of specification and shows how it applies to design detection (i.e., the detection of intelligence on the basis of circumstantial evidence). Always in the background throughout this discussion is the fundamental question of Intelligent Design (ID): Can objects, even if nothing is known about how they arose, exhibit features that reliably signal the action of an intelligent cause? This paper reviews, clarifies, and extends previous work on specification in my books The Design Inference and No Free Lunch.

It’s in eight sections, and the argument in brief goes like this:

We cannot conclude that just because a pattern is one of a vast number of possible patterns that it was Designed; to conclude Design, it has to be one of small subset of those patterns that conforms to some kind of specification. Fisher proposed that if a pattern of data was one that fell in the tail of a probability distribution (aka Probability Density Function, PDF) of patterns of data under some null hypothesis, we could reject the null, but he didn’t give a clear rational for the cut-off point. Dembski suggests that if we have sequence data which a very large number of sequences would be possible under a non-Design hypothesis, and those sequences are binned according to their “compressibility” (ease of description) then they will form a Probability Density Function in which there is a tail consisting of a small subset of easy-to-describe pattern.  Under the non-Design null hypothesis, these will happen rarely.  If, therefore, the number of opportunities for them to happen is low enough, we can reject non-Design.  And if the number of opportunities required to give them a sporting chance of happening at least once in the history of the universe is fewer than the number of events that have occurred in the universe, then we can confidently reject Design.

If any ID proponents think I have mischaracterised Dembski’s argument, I welcome your comments.  But, assuming I have this broadly right, here are the problems as I see them:

  1. He does not attempt to characterise the probability distribution of his compressible sequences under his “non-Design” null, and simply assumes that only Design processes could reliably result in highly compressible patterns that would be improbable under a process that assigned each element in the sequence independently from any other – he does not attempt to argue why this should be the case, and it demonstrably is not.
  2. He does not show how compressibility should be measured (in fact Hazen et al, as discussed here IMO do a much better job, by substituting functional efficiency for compressibility, but their paper does not help Dembski’s case)
  3. He ignores the fact that the very easiest-to-describe sequences (e.g. ranked order sequences) are readily produced by non-Design sorting processes, yet can be highly “complex” i.e. one of a vast number of sorted and unsorted sequences), e.g. Chesil Beach.

Now, there may be various other ID papers proposing some kind of alternative to CSI that tackle some of these problems, but my point is that these three objections are fatal flaws in Dembski’s concept, and that therefore any improvement has to tackle all three.  But it would be interesting to see if there is any disagreement about whether I have his argument right, and what the flaws are.

198 thoughts on “Dembski’s CSI

  1. William J. Murray:

    Since you appear to disagree with Joe F’s definition and use of CSI, you will need to show how you want to calculate CSI in order to give any meaning to this argument of yours:

    unless you can show NS to select more for increased CSI than against increased CSI, you have no basis for the claim that NS adds anything to the search for increased CSI.

  2. Oh. What conclusion are You dedicated to?

    I’m not dedicated to any, because my beliefs don’t rely on supportive conclusions.

  3. William J. Murray,

    The only people that fail to understand what I am saying, in my experience, are those dedicated to a different conclusion.

    So your argument boils down to accusing others of bad faith?

  4. Wings are modifications of structures that were used for other things; and those other structures evolved into something different in other species. Yet most of them retain the “memories” of earlier structures.

    However winding, or through whatever other forms, the path is from scratch to wings, you still are left building wings from scratch.

  5. William J. Murray:
    Elizabeth said: “…yet you are attempting to make a mathematical and scientific point.”

    WJM answered: “No, I’m not.Try again?”

    LOL. Yes, you are:

    Unless you can show that what NS produces as it differentiates between success and failure in practice is in principle a deviation from the mean in favor of increased CSI, then NS is useless as a mechanism for explaining increased CSI. It might increase it (according to Joe F’s method), but it doesn’t necessarily game evolution in favor of it, because, theoretically, it could just as easily reduce CSI.

    *deviation from the mean* = math; *Natural Selection* = science;

    Try again?

  6. William J. Murray: However winding, or through whatever other forms, the path is from scratch to wings, you still are left building wings from scratch.

    And when you are done with that, you will have to explain where scratch came from.

  7. William J. Murray: However winding, or through whatever other forms, the path is from scratch to wings, you still are left building wings from scratch.

    What is benzene built from; scratch?

    How about all the various forms of carbon; from scratch?

    How about complex molecules of any kind; from scratch?

    Does every structure start with “spontaneous molecular chaos” every time it evolves into something different?

    Where do atoms and molecules come from; scratch?

    What do you mean by “scratch?”

  8. William J Murray: “However winding, or through whatever other forms, the path is from scratch to wings, you still are left building wings from scratch.”

    That’s as bad an argument as claiming that someone who writes a “Hello world” application needs to write a new OS and library to support it.

    If you have an arm that’s not a wing, why would you need to create a whole new arm and membrane, instead of just adding a membrane to an existing arm?

    If you already had an arm and membrane, why would you re-create them from “scratch” to add feathers?

    ID, as practiced by humans, re-uses components, and so does evolution.

  9. olegt: And when you are done with that, you will have to explain where scratch came from.

    Don’t forget proto-scratch*

    * Designers are of course exempt from these type of stuff. If they have CSI, they don’t have to declare where *they* got it from.

  10. Joe G: Less variation = less information
    I asked for your reasoning, Joe. That’s just a repetition of your assertion.

    Joe G: The paper does not exist in isolation, Liz. CSI has always pertained to individuals.

    So is this.

    Joe G: reasoning No, NS involves the individual- it is the individuals that are what fitness is all about- the most fit individuals wiithin a population will out-reproduce the less fit individuals.

    Yes, it involves the individual. Yes it pertains to populations. In fact you can only compute selection coefficients with reference to populations.

  11. Joe G,

    Joe G: “I guess my posts will pop-up sometime…”

    This what 99% of Evos go through on UD and it makes debating very difficult.

    I’m not making fun of you, but I do empathize since I’ve gone through it at UD, so please stick around.

  12. Toronto: Joe G,This what 99% of Evos go through on UD and it makes debating very difficult.I’m not making fun of you, but I do empathize since I’ve gone through it at UD, so please stick around.

    Kinda sucks that no-one reads your posts because the threads passed you by. I’m sure if keep it clean though, moderation might be rescinded?

  13. Toronto: That’s as bad an argument as claiming that someone who writes a “Hello world” application needs to write a new OS and library to support it.

    ^ Yes. That. ^

  14. Addendum: It would seem that no one can tell what your conclusion is, so how can anyone tell if they are disagreeing with you?

  15. I was banned from UD under Dave Scott. Banned for two years. When I was unbanned I posted for several months and was put on moderation for disagreeing with Kariosfocus. I was on moderation for six months.

    In none of my posts did i use foul language and in none of my posts did I engage in name calling. I have complete sympathy for moderators who restrict people who call other people names and who use abusive language toward other posters. That’s exactly what moderation is for.

  16. So Joe, it looks like you were wrong when you claimed we have no evidence for mutations producing new biological structures.

    Where did I make that claim?

  17. Elizabeth:
    Joe G: Less variation = less information
    I asked for your reasoning, Joe.That’s just a repetition of your assertion.

    Joe G: The paper does not exist in isolation, Liz. CSI has always pertained to individuals.

    So is this.

    Joe G: reasoning No, NS involves the individual- it is the individuals that are what fitness is all about- the most fit individuals wiithin a population will out-reproduce the less fit individuals.

    Yes, it involves the individual.Yes it pertains to populations.In fact you can only compute selection coefficients with reference to populations.

    The reasoning is if you once had 100 different alleles in a population and one gets culled you lost the information for that 1 allele.

    And computing selection coefficients does not construct new protein complexes.

  18. Joe G:

    T: “So Joe, it looks like you were wrong when you claimed we have no evidence for mutations producing new biological structures.”

    Where did I make that claim?

    In the post immediately above

    Joe G: “What’s to learn, Mikey? You don’t know how many mutations nor to what genes produced any wing, nor any other biological structure.”

    Why are you avoiding my question about the CSI amount of members of a species being identical for all or slightly different for each individual?

  19. What do you mean by “scratch?”

    I’ve already epxlained what I mean by “scratch”.

  20. Joe G: Bats “evolving” into bats doesn’t help you- what was the non-bat population taht gave rise to bats?

    Evidence for non-flying bat ancestors evolving their hands into wings and becoming flying bats directly refutes your claim that such changes can’t happen.

    Now please tell us if the elongated fingers that evolved and allow flight are an increase in CSI or not, and how you can make the determination.

    Having you continually duck questions isn’t conducive to productive discussion.

  21. All of this reminds me of the joke that charisma is that indefinable, ineffable quality that girls with big jugs have. Or in this case, CSI is that incalculable property possessed only by objects we already decided were Designed.

  22. Flint: Or in this case, CSI is that incalculable property possessed only by objects we already decided were Designed.

    Don’t forget the corollary:

    CSI is that incalculable property of objects that can only decrease, never increase, by natural evolutionary processes.

  23. William J. Murray: I’ve already epxlained what I mean by “scratch”.

    Oh, you mean this:

    William J. Murray: When you make a cake from scratch, you’re starting with basic ingredients – flour, sugar, oil, eggs, etc. At some point, all evolution begins with “basic ingredients”, from which wings and immune systems are – over time, even in step by step increments – built from.

    So maybe you could clarify what you think the flour, sugar, oil, and eggs of evolution are, that evolution has to build from to turn a flightless mammal into a flying mammal?

  24. Thorton: Evidence for non-flying bat ancestors evolving their hands into wings and becoming flying bats directly refutes your claim that such changes can’t happen.

    Now please tell us if the elongated fingers that evolved and allow flight are an increase in CSI or not, and how you can make the determination.

    Having you continually duck questions isn’t conducive to productive discussion.

    Umm there isn’t any evidence for non-flying bat ancestors evolving their hands into wings and becoming flying bats. One can only assume it happened- it can’t be tested.

    Try again…

  25. Thorton:
    Here’s another more recent paper on the same topic

    Regulatory divergence modifies limb length between mammals

    So Joe, it looks like you were wrong when you claimed we have no evidence for mutations producing new biological structures.

    I’m curious though – do the mutations for the elongated finger bones of the bat count as new CSI?Why or why not?

    Modifying limb length does not explain the presence of the limbs, ie the structurese, in the first place.

    Keep trying….

  26. WJM:

    The only people that fail to understand what I am saying, in my experience, are those dedicated to a different conclusion.

    We are brothers then, you and I. I am a master communicator, and the only people who fail to understand my meaning are those willful souls predisposed to dismissing it.

  27. Flint:

    CSI is that incalculable property possessed only by objects we already decided were Designed.

    Thorton:

    CSI is that incalculable property of objects that can only decrease, never increase, by natural evolutionary processes.

    Wrong and wrong. CSI is that property of objects that is entirely apparent to even the most humble of ID advocates, yet which even the most able opponent struggles to formulate for real-world examples.

  28. I’m going to stick up for CSI. I think it’s a potentially useful concept, and as formulated by Hazen et al, is readily applicable to biological structures.

    My main criticism of it as a measure is that “compressibility” or “ease of description” is not easy to operationalise. But if we take a short cut and pre-specify a subset of patterns that exceed some threshold value on some function-of-interest, then it seems to me perfectly calculable. As I have done in the new thread.

    The far bigger problem, from Dembski’s PoV, is not that it’s difficult to calculate, but that it’s dead easy to produce by Darwinian processes at levels well within his “rejection region” for non-design.

  29. William J. Murray: The only people that fail to understand what I am saying, in my experience, are those dedicated to a different conclusion.

    The trouble with this claim, William, is that it is intrinsically unfalsifiable.

    Better, IMO,to make the working assumption that when people fail to understand what we are saying that we have either not been clear, or that we have failed to understand their rebuttal.

    That way, we remain open to to the possibility enlightenment ourselves, even if it turns out that our assumptions are sometimes unwarranted.

  30. Elizabeth:

    I’m going to stick up for CSI. I think it’s a potentially useful concept, and as formulated by Hazen et al, is readily applicable to biological structures.

    If someone finds an application, then sure. But it seems that combinatorial problems render the assessment of the boundary impractical. And the ‘information’ is never just in the string. For whatever work we need to do by assessing ‘function’ in a ‘library’ of alternative sequences, we already have tools. They could be improved, but not by formalising what we already know: that some will work and some won’t.

    OK, let’s see if those [sub] tags work

    I(Ex ) = −log2[F(Ex)], where F(Ex ) is the fraction of all possible configurations of the system that possess a degree of function ≥ Ex

    It is true that a fraction of – say – peptide sequences will possess a particular GTP affinity at a particular temperature and pH. We should even be able to compute it in a practical time, for a fraction of the universe of peptide strings below a particular threshold, which could be raised by faster processors or a slicker algorithm. And for sequences below an even lower threshold length, we might be able to empirically assess the entire space for the actual binary bins into which we could split the total space. And this is actually done – ‘libraries’ of short peptides are assessed for function, which allows one to gain more definitive answers to the kind of question that is more typically answered by hot air – the Creationist (after Hoyle) says that the fraction having a particular function is 1/N (and hence practically impossible), whereas we can infer from such experiments that functions are more widely distributed. But what’s CSI for, in all this? The more important metric for evolution is based upon clustering of sequence – not just the total fraction, but the fraction accessible from where we happen to be by ‘typical’ mutational modifications.

    But the other vital ingredient is context. There is one fraction that has GTP binding in the presence of one particular small-molecule cofactor (which rearranges the stresses in the peptide chain) at a particular concentration, another at another concentration, another in the presence of a different cofactor … biological function is ‘context-and-then-some’!

  31. Allan Miller: But the other vital ingredient is context. There is one fraction that has GTP binding in the presence of one particular small-molecule cofactor (which rearranges the stresses in the peptide chain) at a particular concentration, another at another concentration, another in the presence of a different cofactor … biological function is ‘context-and-then-some’!

    Precisely! Nature explores everything that isn’t forbidden. And very little is forbidden.

  32. William J. Murray: My will.

    Nope.

    Try willing yourself to believe in Santa Claus….you can’t. Go on, try it.

    Try willing yourself to believe in X…..you can’t. Go on, try it.

  33. The trouble with this claim, William, is that it is intrinsically unfalsifiable.

    It’s not a claim, it’s a personal observation.

  34. Precisely! Nature explores everything that isn’t forbidden. And very little is forbidden.

    Because something isn’t forbidden by nature doesn’t make “it’s not forbidden by nature” a sufficient, plausible explanation of anything.

    I think this is probably “the” fundamental gap between IDists and Darwinists; Darwinists think that as long as nature doesn’t explicitly prevent something from occurring, then nature can obviously explain it. IDists hold the position that unless some kind of naturalistic explanation has been shown categorically sufficient and scientifically plausible, then nothing has been explained in any meaningful sense.

  35. William J. Murray: I think this is probably “the” fundamental gap between IDists and Darwinists; Darwinists think that as long as nature doesn’t explicitly prevent something from occurring, then nature can obviously explain it. IDists hold the position that unless some kind of naturalistic explanation has been shown categorically sufficient and scientifically plausible, then nothing has been explained in any meaningful sense.

    Categorically sufficient and scientifically plausible to who? People who study and research the evidence for a living almost universally accept naturalistic evolution as the correct explanation. It’s only IDCers with a religious predisposition to automatically reject any evidence they perceive as threatening their world view who disagree.

    In the in the entire history of people doing scientific investigation, every last thing we have found an explanation for has turned out to have purely natural causes, and not a single thing has been found to have supernatural causes.

    Sorry WJM, but science just doesn’t accept “Designer of the gaps” arguments. Not today, not tomorrow, not ever.

  36. William J. Murray: Because something isn’t forbidden by nature doesn’t make “it’s not forbidden by nature” a sufficient, plausible explanation of anything.

    I think this is probably “the” fundamental gap between IDists and Darwinists; Darwinists think that as long as nature doesn’t explicitly prevent something from occurring, then nature can obviously explain it. IDists hold the position that unless some kind of naturalistic explanation has been shown categorically sufficient and scientifically plausible, then nothing has been explained in any meaningful sense.

    This is an important point, but I’m going to propose a third and important position, which, I suggest, the vast majority of non-ID scientists hold:

    1. The position that unless some kind of naturalistic explanation has been shown categorically sufficient and scientifically plausible, then nothing has been explained in any meaningful sense.

    2. The position that as long as nature doesn’t explicitly prevent something from occurring, then nature can obviously explain it.

    3. The position that there is no way of telling whether a natural explanation can be found or not except by seeking one.

    In other words, while ID proponents claim that the evidence indicates that “non-Design” is wrong, non-ID proponents, in general do not make the symmetrical claim that ID is wrong.

    In my experience of discussing evolution with ID proponents I find that there is a strong assumption that non-IDists are making the positive claim that there is no ID (presumably accounting for the extreme bitterness some ID proponents show towards “Theistic Evolutionists”). Anyone making the positive claim that science shows that there is no ID is making a non-scientific claim, IMO.

  37. Thorton: Categorically sufficient and scientifically plausible to who?

    Lawyers.

    Thorton: People who study and research the evidence for a living almost universally accept naturalistic evolution as the correct explanation.

    Yes, and? People state that they ‘believe’ all sorts of things when income and social status is involved. Doubly so when the person’s income is derived from ‘believing’ what they state they believe and when their status, and thus access to high-quality mates, is predicated on their stardom as a ‘believer’.

    Which is precisely what we should expect from evolution. That we’ll mouth nonsense and murder our neighbors for filthy lucre and suggestively deposited bits of adiopose tissue. And, of course, you’re mouthing what the ‘high status breeders’ mouthed so you can likewise gain accesss to suggestively deposited bits of adiopose tissue.

    So there’s the evidence. Now where’s the empiricism?

  38. Ah. So, I must assume that you think your will is not shaped by evidence and conclusions?

    I know it isn’t. But then, I have free will. Not everyone does.

  39. Maus: Lawyers.

    Yes, and?People state that they ‘believe’ all sorts of things when income and social status is involved.Doubly so when the person’s income is derived from ‘believing’ what they state they believe and when their status, and thus access to high-quality mates, is predicated on their stardom as a ‘believer’.

    Which is precisely what we should expect from evolution.That we’ll mouth nonsense and murder our neighbors for filthy lucre and suggestively deposited bits of adiopose tissue.And, of course, you’re mouthing what the ‘high status breeders’ mouthed so you can likewise gain accesss to suggestively deposited bits of adiopose tissue.

    So there’s the evidence.Now where’s the empiricism?

    What the hell is that pile of dung supposed to mean?

  40. From early comments:

    Joe Felsenstein:
    I have always been less critical of the general notion of CSI than have most critics of Dembski.In essence, if we take fitness as the scale on which to measure, CSI is just a fitness value too high to reasonably come about (even once in the history of the Universe) by pure mutation.I think organisms in general meet that criterion and this is not controversial — could pure mutation (without natural selection) lead to a species as well adapted?Of course not.

    Posing CSI in terms of a fitness scale also avoids all the squabbling about which among us really understands information theory.

    Where the argument goes wrong is not the CSI part but in saying one is detecting Design.In fact, one is successfully detecting either Design or natural selection or both.The only reason Dembski believes it is detection of Design is that he thinks his Law of Conservation of Complex Specified Information rules out that the amount of adaptation could be due to natural selection. I have argued (invoking work by others, particularly Elsberry and Shallit 2003 plus some new arguments of my own, that Dembski’s LCCSI cannot do the job, so that CSI can be due to natural selection, as that has not been ruled out.

    Elizabeth:
    I agree, Joe.It seems to me that CSI is a potentially useful concept (and in the paper by Hazen et al, actually works).I think it tells us something interesting about any pattern that displays it – in fact, I think it tells us that it was “intelligently designed” if we use Dembski’s own definition of “intelligence” as something with “the power and facility to choose between options”, which of course is what natural selection does.Moreoever, I’d say that natural selection is a good description of how our own intelligence works, with excitatory/inhibitory connections and Hebbian learning serving the role of differential reproduction.

    It’s not CSI I object to, it’s his assumption that something with CSI (and I’d be happy with a much less stringent alpha than is UPB) must not only be “intelligently” designed (by his definition) but intentionally designed.He just assumes this must be the case.He does not even present an argument for it.

    It’s the elephant in the room of ID, but, as far as I can see, dismissed by the assumption that “chance” means both “non-intended” and “equiprobable”, and that if something is not “equiprobable” it must be “intended”.

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