The failure of the explanatory filter: Unreliability

| 61 Comments

Updated with some missing text and edited for content June 15

A recent article in Physics Today discusses the search for SETI using optical detectors. On Uncommon Descent, Dembski claims that OSETI shows how the explanatory filter is used in sciences. Since Robert Camp already has shown why such a claim is inappropriate for SETI, I would like to explore Dembski’s latest claim as it applies to OSETI.

I will quote from the article to show how OSETI mimics the explanatory filter in the sense that it can generate false positives. Ironically, Dembski quotes the same passage, which suggests that Dembski accepts false positives for his explanatory filter, and which would render the filter useless.

OSET is, like SETI, an attempt to detect intelligently designed signals but unlike SETI ,which focuses on narrow band signals, OSETI relies on nanosecond optical pulses which it claims are more likely generated by intelligent sources because of the lack of known natural mechanisms that would generate such pulses.

Because no known astrophysical source could put out a bright nanosecond optical pulse, some SETI searchers have concluded that looking for signals from technologically advanced aliens is more promising with optical telescopes than with radio telescopes

If we find nanosecond pulses, we can’t lose,” says Horowitz. “If it’s not from an alien civilization, at least we will have discovered an astrophysical phenomenon that no one anticipated. Not a bad consolation prize.

Source: Physics Today, June 2006, http://www.physicstoday.org/vol-59/[…]-6/p24.shtml

In other words, if nanosecond pulses are found, science will be in a a ‘win-win’ situation since either the pulse indicates intelligent design or the pulse indicates a new astrophysical phenomenon. In other words, a design inference in OSETI, unlike the Explanatory Filter, still leaves open a natural explanation.

Based on this article, Dembski claims that:

Dembski Wrote:

These SETI researchers are therefore using optical telescopes as an explanatory filter.

The approach mimics to a limited exent the Explanatory Filter in the sense that the researchers are very well aware that their approach can lead to false positives. This means that ‘design inference’ by itself does not resolve the issue of apparant versus actual design since we cannot exclude the real possibility of having missed a scientific explanation. In order to strengthen the ‘design inference’, these scientists add, as I will show, assumptions to their hypothesis which address such issues as means, motives and opportunities.

We should not underestimate the impact of reliability on the usefulness of the Explanatory Filter. Dembski is very clear:

Dembski Wrote:

“On the other hand, if things end up in the net that are not designed, the criterion will be useless.” Dembski, William, 1999. Intelligent Design: The Bridge Between Science & Theology. P 141.

This is because ID refuses to accept the need and requirements of adding additional assumptions to the hypothesis. Let’s look at some relevant papers. I predict that we can quickly reject Dembski’s claim.

First of all let’s look at Robert Camp’s analysis of SETI and the explanatory filter

Camp quickly points to the differences between a design inference based on the Explanatory Filter and how science applies design inferences.

Camp Wrote:

It is my intent to demonstrate that the analogy fails because, first, in ID the distinction drawn between necessity/chance and intelligence is a terminus, it is the goal and the end of the process. In forensics, cryptography, and archeology this distinction is merely an expedient without which the science itself would not take place. Second, although Dembski wishes to paint ID with a coat of science borrowed from these disciplines, the methodological locus between the two is not analogous. And third, the kinds of phenomena ID investigates are not comparable to those dealt with by SETI, forensics, cryptography, and archeology. ID phenomena are inaccessible to science.

Camp even accepts that the Explanatory Filter is a legitimate approach, even though the evidence strongly supports that it is inherently unreliable, leading one to reject the EF approach ‘a-posteriori’ as useless.

Camp Wrote:

For the purposes of discussing the value of an analogy between ID and SETI (and other sciences), however, we can accept for the moment the legitimacy of the EF. It is my intent to demonstrate that the analogy fails because, first, in ID the distinction drawn between necessity/chance and intelligence is a terminus, it is the goal and the end of the process.

Camp points out that the assumptions and methodology behind SETI are quite different from the rarefied design inference attempts by the Explanatory Filter.

Camp Wrote:

It is obvious that this is something quite different from the assumption of intelligence behind an unexplained phenomenon. As with forensics, SETI investigation is a process that employs specific assumptions about the intelligence it investigates. SETI as a science is more than just an attempt to distinguish between necessity/chance and design. Cornell astrophysicist Loren Petrich makes this point clearly,

These reasons are very distinct from Dembski’s Explanatory Filter, which focuses on alleged unexplainability as a natural phenomenon; they are an attempt to predict what an extraterrestrial broadcaster is likely to do, using the fact that they live in the same kind of Universe that we do.

Let’s look at some relevant OSETI papers and websites to show how Dembski’s thesis quickly unravels

With “Earth 2000” technology we could generate a directed laser pulse that outshines the broadband visible light of the Sun by four orders of magnitude. This is a conservative lower bound for the technical capability of a communicating civilization; optical interstellar communication is thus technically plausible.

SEARCH FOR NANOSECOND OPTICAL PULSES FROM NEARBY SOLAR-TYPE STARS

In other words, with present technology we can create a directed pulse laser that could be visible to other civilizations. In other words, OSETI assumes that there exists similarly or more advanced civilizations who have an interest to be detected by other civilizations. In other words, we are making already assumptions about the motives and means of the designers and we are constraining them to known technologies.

and

Optical SETI versus Radio SETI

Several arguments exist for the choice to search for signals in the optical region of the electromagnetic spectrum over the radio portion. These reasons stem primarily from the benefits for another civilization to send a beacon or signal in the visible rather than in the microwave. Briefly, some of the reasons include:

  • Visible light-emitting devices are smaller and lighter than microwave or radio-emitting devices.
  • Visible light-emitting devices produce higher bandwidths and can consequently send information much faster.
  • Interference from natural sources of microwaves is more common than from visible sources. (See the technical paper on OSETI for additional details.)
  • Naturally occurring nanosecond pulses of light are mostly likely nonexistent.

What is OSETI?

Again we are discussing claims of motives. The fourth assumption is based on our current knowledge. No wonder that the authors are very aware of the real possibilities of a false positive. While for ID, the design detection would be the end, for science the design detection would be the beginning of additional research.

So how would we deal with rarefied life forms, in other words, life which is significantly different from us. How can we constrain the motives and means of such life forms? Expressing her skepticism about the problem facing ID, she points out that detecting life we don’t know or cannot constrain seems an unresolved issue. In fact, as Wilkins and Elsberry have shown in their paper, this is the difference between ordinary and rarefied design.

Life-forms that would send signals would probably be very different from us, says Carol Cleland, an associate professor of philosophy at the University of Colorado. It all makes her slightly skeptical.

“How do we search for life as we don’t know it?” she says

A brilliant discovery the hope of team behind new telescope San Diego Union Tribune

A critical reader on UcD comments:

Mark Frank Wrote:

The paper is subscription only and rather expensive so I have to base this on the quote only.

Consider for a moment why they are looking nanosecond impulses. There must be an infinite amount of potential phenomena that have “no known astrophysical source”. Are we to conclude an alien civilisation every time we come across a new phenomenon for which we do not know the source? Of course not. The reason is that man has developed laser technology that makes this particular phenomenon possible. So now if we were to observe this phenomenon we have some reason for adopting a human-like civilisation as an explanation.

Excellent point, we are looking for laser pulses because we have developed laser pulse technology.

From the quote it appears that despite this they would not dismiss the alternative type of explanation “an astrophysical phenomenon that no one anticipated”. So if the phenomenon occurred there would then be some further assessment of possible causes.

What role does the filter play in all this reasoning?

Excellent question. How does the filter play in all this reasoning and how is the possibility of false positives resolved? In other words, how do we estimate the probability of a design inference versus ‘we don’t know’? Unless we can estimate some probabilities for the design inference we cannot reject the we don’t know explanation. Both can in principle explain the observations as both are based on our ignorance.

On ISCID, Gedanken raised this as one of the many problems with the explanatory filter

C19 Take a case in which the prior probability is extremely low that a designer can effect the potential “design” being observed. (By this I do not mean that this is a generally usable method for evaluating cases, rather I am specifying that in this case that prior probability can be known. I do not mean that such prior probability can regularly be known.) Also assume that there is a rather high probability that something was missed in the steps of analyzing chance and necessity in the explanatory filter. (In other words that the “argument from ignorance” aspect actually may have an important case that the observer is ignorant of, and this is a high probability in this case.) In this case the Bayesean posterior probability that the “designer did it” is often lower than the posterior probability that the missed case is the explanation. Now considering cases in which the prior probability is unknown (a basic assumption of the normal application of the “explanatory filter”) the reasonableness of the EF is dependent on the actual prior probability, though unknown. If one has certain religious reasons, for example, of having differing views of that prior probability, then the result changes based on those views. The EF is not an objective methodology, and its “reliability” differs depending on precisely that prior probability.

Gedanken’s critiques on ISCID are very insightful

The practical usage of the EF actually smuggles this concept of doing the comparison of prior knowledge of structure of designer action into the process (even though explicitly eschewed by the formal steps). If one codified this smuggling into formal process steps (made it explicit) then one may develop a procedure that does not suffer from the limitations that Eric is referring to. (But of course such a codified version may not be applicable in the areas of interest to those in the ID movement, such as historical investigations of biology.)

In other words, the major difference between the EF and how science applies design inferences is that science makes explicit assumptions based on prior knowledge of the structure of designer actions while the EF explicitly disclaims that such assumptions are needed. The reason why ID takes this flawed step is that the design of interest is not really open to such assumptions.

Seems that Dembski’s claim that OSETI applies the explanatory filter could benefit from a more rigorous analysis showing that indeed OSETI applies the EF methodology and does not smuggle in any information. ID should be able to stand by itself and should not depend on riding the coat tails of science. Especially since ID activists have argued that ID, unlike Methodological Naturalism, does not reject a design inference ‘a-priori’. I guess that Dembski implicitly is admitting that science and by logical extension methodological naturalism, does apply design inferences quite reliably.

To understand why some design inferences are more reliable as others and how to resolve the unreliability issue with the explanatory filter, I suggest that readers check out the excellent paper by Wilkins and Elsberry titled The advantages of theft over toil: the design inference and arguing from ignorance.

61 Comments

There is a problem with this post:

Syntax Error: mismatched tag ‘kwickxml’

Syntax Error Detail: mismatched tag at line 43, column 2, byte 4116 at /usr/local/lib/perl5/site_perl/5.8.7/mach/XML/Parser.pm line 187

PT’s slip is showing.

Liz Craig Wrote:

There is a problem with this post:

Syntax Error: mismatched tag ‘kwickxml’

Then maybe the post has been rejected by the design filter?

How are “[t]hese SETI researchers … therefore using optical telescopes as an explanatory filter”? They are looking for something, which no known astrophysical source has put out. That is, we are not dealing with something observed, but something not (yet) observed. Is the EF supposed to work with imaginary “observations”?

I disagree with Camp. In principle, there is nothing too different between the EF and SETI. As Dembski says, both are looking for “design in nature”. While it is true that some of the SETI signals are similar to what “humans” might expect from a civilization, in principle, this is only because we can only conjure up such signatures based on our own experience.

The fundamental difference between SETI and the EF is that SETI HASN’T MADE ANY CLAIM TO HAVE FOUND ANY SIGNAL. Furthermore, even if they found some weird signal THEY WOULDN’T CONCLUDE THAT IT WAS FROM AN ALIEN CIVILIZATION WITHOUT FURTHER RESEARCH.

As the writer so succinctly indicates, they still allow for LAW or CHANCE after they find the signal.

The ID folks, on the other hand, believe the EF has ALREADY found evidence for design and they believe that no further work is necessary to prove this fact.

In principle, though with many limitations, the EF could be used to find EVIDENCE (but not proof) of design. However, it has never been used as such and probably never will be because the probability calculations are near impossible and no one has an idea how one can determine if something is specified within the natural world outside humans ability to make analogies such as Flagellum = outboard motor.

However, it has never been used as such and probably never will be because the probability calculations are near impossible and no one has an idea how one can determine if something is specified within the natural world

Minus the mathematical trappings, I think we use the EF all the time. We look at something and say “Does this seem designed?” We can get false positives or false negatives only if we are willing to admit error, something Dembski is not.

Dembski’s treatment goes no further than to embed his prejudices in a maze of formulas and symbols to make it look quantitative. But all the formal EF does is ratify a conviction arrived at beforehand. The ‘real’ method seems to be to pray, have God answer the prayers in accordance with the supplicant’s preferences (God never answers a prayer by telling someone he’s incorrect), and thus armed with infallibility, construct a specification.

So the meaningful difference here isn’t that SETI hasn’t made any claims or drawn any conclusions. It’s that SETI is constructed to base tentative conclusions on collected data, rather than to base selected data on unshakeable conclusions. Dembski’s EF works only when the ‘right’ answer is already known.

Flint,

I think your problem is with Dembski’s incorrect implementation and false conclusions using the EF, not the EF per se, which, as you say, can certainly give false positives. Yes ?

bdelloid:

Not quite. Dembski constructed the EF for the express purpose of rationalizing his religious convictions. It’s not that he’s using it wrong, it’s that it was created for purposes very different from what it is represented to be for.

The basic problem with Dembski’s EF is that it presumes Dembski’s religious doctrine (that God created life) as the default. It examines a couple of poorly-defined alternatives (and very carefully disallows feedback interactions between these alternatives), discards them, and concludes the assumption he started with.

Equally carefully, it neither defines nor tests the default. And so we can never know what the default actually is, we can only know that Dembski thinks he has eliminated the possibility of whatever his religion rejects.

This is not a filter. It’s only another way of restating his faith.

Another meaningful difference is that the SETI folks are required to make certain assumptions about the ETs they’re looking for, and choose their actions based on said assumptions; while the IDers, for obvious political reasons, explicitly refuse to make any assumptions about their precious “Designer,” and thus have no starting point for their research, observation, or experimentation (which they never intended to do anyway).

PS: I find the assumption that ETs will use light – or any other EM frequency – for interstellar communication to be extremely untenable. Light takes years to travel from one solar system to even its nearest neighbor, so why would any civilization use it? The most we could expect would be stray radio signals from broadcasters, like the BBC or VOA, who aren’t trying to be heard by anyone other than their local audience.

Pray tell, what should SETI be looking for other than light?

Flint,

You say:

“It examines a couple of poorly-defined alternatives and … concludes the assumption he started with.”

The EF does no such thing. The conclusion is made by an implementation of the EF, not the EF itself. This is not so say that the EF doesn’t have flaws (specification is a jello concept, the categories are not necessarily mutually exclusive, etc.)

Nonetheless, your issue here is the awful implementation of the EF by Dembski and mistaken conclusion, not the EF per se. The EF can stand alone, seperate from someone who doesn’t know how to use it correctly. For example, I think the use of the EF to distinguish between sorted and unsorted decks is entirely correct. And pre-specification is correctly applied there.

Dembski Wrote:

These SETI researchers are therefore using optical telescopes as an explanatory filter.

MacGyver has nothin’ on SETI.

Flint,

You say:

“It examines a couple of poorly-defined alternatives and … concludes the assumption he started with.”

The EF doesn’t conclude anything. The conclusion is made by an implementation of the EF, not the EF itself. This is not so say that the EF doesn’t have flaws (specification is a jello concept, the categories are not necessarily mutually exclusive, etc.)

Nonetheless, your issue here is the awful implementation of the EF by Dembski and mistaken conclusion, not the EF per se. The EF can stand alone, seperate from someone who doesn’t know how to use it correctly. For example, I think the use of the EF to distinguish between sorted and unsorted decks is entirely correct. And pre-specification is correctly applied there.

bdelloid Wrote:

The EF can stand alone, seperate from someone who doesn’t know how to use it correctly. For example, I think the use of the EF to distinguish between sorted and unsorted decks is entirely correct.

I’m with Flint on this one. We conclude design from a sorted card deck not because of the EF, but because we know from experience that this particular type of regularity is human-intentional. We also know from experience that other types of regularity are natural. If we encounter a regularity with which we have no experience, the EF says it must be designed, which is completely unjustified. So the EF is either unnecessary or unreliable.

Whatever EM frequencies would be useful for communication within a solar system, but also, coincidentally, able to travel interstellar distances with minimum absorbtion, diffusion or contamination. (Does light fit that bill?) Or something we haven’t invented yet, like faster-than-light or hyperspatial communications.

Physics Today Wrote:

If we find nanosecond pulses, we can’t lose,” says Horowitz. “If it’s not from an alien civilization, at least we will have discovered an astrophysical phenomenon that no one anticipated. Not a bad consolation prize.

Mark Frank, a poster on UD, made the same point – that the pulse might come from a natural source. For agreeing with the article, Mark was shown the door. Logically, then, Dembski should be booted also.

raging bee Wrote:

Whatever EM frequencies would be useful for communication within a solar system…

EM radiation = photons = light. Too bad there’s that pesky upper limit information trasmission, which is the speed of light.

Flint Wrote:

Minus the mathematical trappings, I think we use the EF all the time. We look at something and say “Does this seem designed?” We can get false positives or false negatives only if we are willing to admit error, something Dembski is not.

I think this is incorrect; we use nothing like the EF in everday life.

Whatever Dembski means by it, the EF explicitly relies on probability calculations based on possible causal histories to make its determination. We don’t do that in everday life; in life, we do pattern matching - our brains have sufficient experience with things that humans have created that we can match probables against that mental catalogue. We don’t pick up a rock from the side of the street and determine probabilities of its having that smooth shape based on geological processes; we note that it looks like a billiard ball.

Humans do pattern matching, not pattern recognition.

To claim that we use the EF in daily is simply according respect to Salvador’s lunatic claim that the EF is merely a formalization of something we already do. Which is nonsense.

And to think the quickest thing available for transmission of the WORD of G…er the grand old designer 6K years ago were a few fast talking Rabi’s who when claiming to be transcribing the words of the most powerful force in the universe (according to those who claim to know the one true WORD of G..er the designer) could have just asked him/them to download the whole lot as an mp3 to their ipods.…D’oh. Hey don’t laugh .…apparently he/she/them has (indirectly) created a huge laser on another planet.…just like here.

On the other hand WilliaMAD (President For Life of the WADembski appreciation club) could really clean up here, (here’s your chance big boy.…Get your EF implemented in silicon and installed on every telescope on the planet and cash in those royalties.….have a cigar on me)Just fix up those pesky details .….such as ,oh…being more useful than say a house brick.

The problem with Dembski is the specification issue. Scientists can look for simple or complex designs. In the case mentioned here, they are looking for simple ones, but there is nothing that inherently prevents them from looking for complex signals.

How do decoders discover “intelligence” in a code? They look for symbols and patterns that are known to our intelligence. With aliens, we might look for knowledge of basic physics, with Nazi codes we might look for mentions of “Berlin”, “Hitler”, physical and engineering information, and geographical data. That is to say, we look for information that intelligences that we are familiar with can learn, and thus specify in their languages and codes.

We don’t just look for complex order. Complex systems do evolve, and not just the biological ones. For instance, no real scientist would mistake earth’s biological organisms for being “designed”, not only because they do not conform to designed objects, but also because life has specific characteristics that we know only through observation, and not by being able to think to specify “a bird” without first seeing one.

Send the raw genetic data for a bird out among the stars, and an intelligence quite different from ours (one that has not encountered similar genetic codes, that is), would not know the source of this information. This alien might very well know that the signal itself was “intelligently designed” (acceptable terminology here, but hardly the best), but there would be no indication that this information was specific to anything designed, vs. the result of some complex “natural” evolution.

Send some specific and simple information, like the plans for a modest commercial building, and the alien may have a good idea that this information was designed. There are specific, “specifiable” data in such a plan, something recognizable by intelligence. Complex designs would be harder to identify, yet presumably could be identified with enough intelligence and/or computing power.

To identify intelligences, we compare specific information that known intelligences are capable of recognizing. We do not compare contingent information, like that encoded in DNA, in order to detect “design”, for we do not know of any intelligence that could make known organisms de novo, nor any reason why this intelligence would specify a bird to be as it is (beyond the constraints of the system, anyhow).

Let’s put it this way: The plans for solar cells might very well be identifiable in alien signals. The Rubisco enzymes of plants are only explainable via contingency, since plant Rubisco is in fact poorly “designed” for present environments. It works well enough in cyanobacteria, from which it was derived, because carbon dioxide dissolves readily in water. But in C3 photosynthesis, it wastes considerable energy, while C4 photosynthesis “solves” the problem only through considerable expense.

No intelligence would know to specify the broad outlines of plant Rubisco through principle, as one may with silicon solar cells. Rubisco only makes sense via contingent evolutionary development, thus it is a non-marker for intelligent design.

Dembski calls his CSI “complex specified information” only because some (perhaps himself) confuse the specification of evolutionary contingent information from generation to generation (necessary for reproduction), with the specified information that we really could detect in many messages. The two sorts of specification are not at all the same, since we look for specified non-contingent information as much as possible when we try to detect design in scenarios where contingencies remain unknown.

Dembski possibly does not know the difference between the (largely) determistic specification necessary to support reproduction and evolution in organisms’ ongoing contingent adaptations to the environment, and the rationalistic specifications of designers. We look for the latter when looking for unknown intelligences (with known intelligences we might very well look for contingent evolving information), because the former betrays nothing of design. Dembski looks for the former because he already “knows” that God designed life.

Dembski looks for complex contingent information when using his EF, because he wants to define organisms as “designed”. In so doing he turns his back on the actual practices of codebreakers and SETI researchers, who look for both simple and complex rationalistic information. He is not looking for rational design, he is looking to baptize non-rational design as “intelligent design”.

Glen D http://tinyurl.com/b8ykm

For sale - one Explanitory Filter, still in box, never used. Instruction manual has significant wear and pages missing, however.

Rilke’s Granddaughter: “Humans do pattern matching, not pattern recognition.”

Do you have any sources for this assertion? I am personally interested in this subject, and have not heard this before.

I decided that I should emphasize an issue with which I concluded my recent post.

We mostly look for rational design when looking for design by unknown designers. This is particularly true for alien signals, since we don’t know the contingencies affecting aliens, while we expect intelligences to in fact be rational, at least in their functional designs.

Why isn’t Dembski looking for rational design as the mark of intelligence like a true scientist would? This is because he either knows or suspects that he won’t find it (ok, IDists more or less suggest it with their analogies of biological machines, but indeed that is why they resort to analogies–because they can’t show rational design). So he looks for what he can find in organisms, and simply calls it “design”, which we may confidently attribute to his belief that “without Him not anything was made that was made” (John the 1st chapter, referring to Jesus).

We do not at all times look for rational design with humans, of course, for we know their foibles, faults, and emotions. However, what we do expect to be common among all things that we would label “intelligent” is the capacity for “rational design”. That Dembski pointedly avoids looking for rational design in organisms shows that on some level he know that he is not looking for identifiable intelligent design.

Glen D http://tinyurl.com/b8ykm

bdelloid Wrote:

In principle, there is nothing too different between the EF and SETI. As Dembski says, both are looking for “design in nature”. While it is true that some of the SETI signals are similar to what “humans” might expect from a civilization, in principle, this is only because we can only conjure up such signatures based on our own experience.

Not to claim to be an EF expert; but I do believe to have understtod that you use the EF to analyze an existing observation. At best/worst we can say that SETI is applying prejudice to pre-filter observations.

Anyway, in what way is there specified complexity in short light bursts? And how much of it?

cheers

Seems like this EF thingy is testable. Seems like Dembski is saying that he has an algorithm for sorting binary strings into categories called “Designed” and “Not-designed”. If indeed he has such a computer program I invite him to share it with us.

GuyeFaux

Raging says:

“PS: I find the assumption that ETs will use light — or any other EM frequency — for interstellar communication to be extremely untenable. Light takes years to travel from one solar system to even its nearest neighbor, so why would any civilization use it? The most we could expect would be stray radio signals from broadcasters, like the BBC or VOA, who aren’t trying to be heard by anyone other than their local audience.”

I’m not a SETI expert so you will have to check this. But EM radiation is the easiest spectra that we can currently can observe. For example, gravitation waves aren’t doable today, neither neutrinos really.

The stray signals aren’t as directionable so they die out faster. The idea to look for directionable EM is that SETI:s may send out “Hello World” messages to selected stars, as we have done once and perhaps will continue to do one day. Light is easy to direct.

RGD:

To claim that we use the EF in daily is simply according respect to Salvador’s lunatic claim that the EF is merely a formalization of something we already do. Which is nonsense.

I understand your distinction, but I argue that I already drew that distinction very carefully, twice. Dembski’s EF purports to be a pattern recognition system, and I argued that it was not and could not be used that way. I carefully explained that the EF is an ex post facto rationalization for a conclusion already drawn using entirely different mechanisms.

Which is what we all do in daily life, as you say. Dembski constructed the EF to put a rigorous formal veneer on the same sort of everybody-has-one opinion he actually uses, but does not wish to concede is fallible.

I’ve written previously that absent a considerable database of experience (I mentioned landing on a totally unfamiliar planet), Dembski’s EF would be no more accurate than throwing dice.

Guy Wrote:

Seems like this EF thingy is testable. Seems like Dembski is saying that he has an algorithm for sorting binary strings into categories called “Designed” and “Not-designed”. If indeed he has such a computer program I invite him to share it with us.

The problem is that Dembksi has never actually used the filter on anything. Anything. Not one darn thing after all these years. More importantly, he’s never once worked out how one would actually apply it.

F’r example, consider the following two binary strings:

A: 000000000000000000000000000000000 B: 111111111111111111111111111111111

What do we need to do to apply the filter? We need to determine the probability of the occurence of each string based on the causal history of those strings. Or on potential causal histories of those strings. Let’s say they both were generated by ‘random number generators’, with a small bias: the odds of getting a ‘1’ are less than 1 in 1/10^300.

In that instance, string A is highly probable, and conforms to a pattern; and string B is highly improbable and yet conforms to a pattern.

Dembski’s EF would label string A as natural; and string B as designed.

More importantly, the filter requires us to calculate the probability of causal histories without any knowledge of the actual circumstances of those causal histories - we calculate ‘blind’ as it were.

So not only in the EF completely unlike anything that humans do in real-life; it cannot actually be applied. Ever.

Rilkes Granddaughter Wrote:

So not only in the EF completely unlike anything that humans do in real-life; it cannot actually be applied. Ever.

Ignoring the (colossal) problem with Dembski’s mis-use of probabilities, his claim is that an algorithm exists which can reliably sort strings into two categories, correct?

Flint Wrote:

I understand your distinction, but I argue that I already drew that distinction very carefully, twice. Dembski’s EF purports to be a pattern recognition system, and I argued that it was not and could not be used that way. I carefully explained that the EF is an ex post facto rationalization for a conclusion already drawn using entirely different mechanisms.

Which is what we all do in daily life, as you say. Dembski constructed the EF to put a rigorous formal veneer on the same sort of everybody-has-one opinion he actually uses, but does not wish to concede is fallible.

I’ve written previously that absent a considerable database of experience (I mentioned landing on a totally unfamiliar planet), Dembski’s EF would be no more accurate than throwing dice.

OK, so maybe we’re arguing terminology. The problem is that the EF is a very specific algorithm - an algorithm that we do not apply in daily life.

What you are arguing is more nuanced; certainly too nuanced for the average ID advocate or critic. Your argument is that the EF is a false formalization of an entirely different algorithm, one that we do apply in daily life.

In that sense, you are right - but your phrasing implies that the filter as written is something we all do, which is false.

OSETI gets a signal that looks like it fits their criteria, they’ll say… “Hmm, this is interesting… let’s investigate this further.”

Behe shows Demski a flagellum and WAD says “See? I told you so!”

Arrrggghhh again. OK, if you go to the Creation “Science” Debunked website, at:

http://www.geocities.com/lflank

and scroll down near the bottom, above the “Resources” section, there’s a link to the PDF there.

I *hate* Geocities. Really I do. Grrrrrr.

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