Please understand that I'm not defending ID as a science, nor am I saying that they've produced much that I'm convinced of. Quite the opposite, I have some resounding criticisms of the movement--you'll see them in my post above, and I'll outline some more below. -But- I do think the movement is centered around legitimate questions, and the study is a legitimate one. And I think it's foolish for people to blow it off, look for weaknesses, try to debate without trying to understand. For all its flaws, ID asks a good question, and so I'm watching with interest to see if they ever answer it.
Let me distinguish between ID as a general pursuit, and ID as a position on something.
ID as a general pursuit allows for "design" as an explanation for things, along with "law" and "chance," and looks for good principles to use to establish design. In this sense, ID is huge and far-reaching. When we separate spam from email, we're practicing ID--detecting which words have minds behind them, and which are script-generated garbage. When we detect bugs in software, we're practicing ID--detecting which features were intended and which were accidental. Archeology practices ID in this sense, distinguishing manmade things from natural ones. Forensics practices ID in this sense, distinguishing accidental death from murder. Interpretation of text very heavily practices ID--detecting the author's intent from the words. In this sense, ID is ubiquitous, but fuzzy and intuitive: nobody has good, general rules for detecting design. We just do it, and for everyday situations, intuition is enough; technical situations often have their own rules (i.e., archeologists look for evidence of human production, forensics looks for method, motive, opportunity, etc.), but there is no real overarching, scientific, philosophically grounded way to judge these rules. ID seeks to establish one.
It would be nice to have one. It would be nice to have something we could apply to, say, Biblical prophecy and say, "Ok, here's the prophecy, here's the supposed fulfillment... according to this Magic ID Formula, here's how impressive that really is. It was probably [design/chance fulfillment]." My dad was talking to me about something in the Bible recently, talking about a numeric sequence the ages of three patriarchs made--5*5*9, 6*6*8, and 7*7*9... or something like that. And my ID instincts immediately kicked in--was that a "good" pattern for evidencing design? Or was it just chance--a pattern mined after the fact from really meaningless data? It would be nice to have methods and principles. At present there are none. We just use our intuition ("Well, that seems improbable, but it's kind of a weird pattern..."). ID, if it developed well as a theory, could have great application in clarifying these sorts of things.
ID as a position on a topic is to say that there
is evidence of design there--that is, to choose "design" out of the "design", "chance", "law" trichotomy. So an ID position on a Bible prophecy would be to say, "I think someone fulfilled this on purpose--it matches too well to have happened by chance." An ID position on a forum post would be to say, "I think someone wrote this--it makes too much sense to have come about without a mind." An ID position on origins says, "I think someone made this universe--it's too cool to have come about without a mind."
Of
course ID as an origins position is unbelievably broad--that's a consequence of the theory! To use that as a criticism is like saying the "old earth" position on origins is unbelievably broad (after all, it allows old earth creationists, directed panspermia-ists, theistic evolutionists, naturalistic evolutionists... actually, pretty much anybody except the young earth creationists). Of
course it's broad--it only makes a single, specific claim. Anybody who adopts that claim is compatible with the position.
ID as an origins position says only that certain things--biological things, life in general, or the universe (depends on the topic--see above where I outlined possible ID positions at different levels)--looks designed, and moreover that design is not only apparent but real. ID is to look at the inner workings of a cell and say, "This is too cool to have come about by chance; someone must have done it."
I know people are anxious to discard ID as a position on origins. I know people want to discard ID as a general pursuit because of the position on origins (an intellectually dishonest mistake--if ID as a general pursuit succeeds, and origins really are naturalistic, it will show that.) I know the responses. Lack of detail in a particular piece of a naturalistic theory isn't the same as saying no naturalistic theory will account for something. IDers should just be patient, naturalists will explain everything in time. Stuff with the anthropic principle. Stuff about science studying nature, not the supernatural. There are responses to all of these--lack of a naturalistic theory, in the face of something that looks designed, is itself evidence for design. Patience is only good when an outcome seems likely. The anthropic principle explains only why we see things, not why they are there. Science may study nature, but it studies minds, too--an intellectually honest scholar would not discard design out of hand. Things get more complicated, and we want to go down that road, we can. And ID has its flaws, I'll make no bones about that--it's overly political and its methods don't work. But at the end of the day, ID asks a good and reasonable question, and it would be foolish to get so caught up in the game of debate that we ignore the question.
Just how designed does something have to look before you can say it is? Woodpeckers' beaks are well suited to pecking holes in things--are they just well adapted, or is that design? (The clear answer is natural adaptation.) Fusion cannon is well-suited to taking out robot generators--is that clever usage or design? (Probably clever usage, though it might be design). Birds' wings are well-suited to flight--is that adaptation or design? (People start to diverge here...) And what of the other things we find in nature--what of the outright machinery within the cell? Assembly lines, pumps, motors, libraries--is this impressive enough that the design inference is valid? What if we found a probe on mars that could do all the things a cell can? We'd certain infer design, wouldn't we? So are we being intellectually honest if we keep looking for naturalistic theories to explain the origin of life--or are there principled distinctions? Is all design an illusion? What if DNA contained a book, or a computer program? Would it be okay to infer design then?
People are inclined to brush off the questions, and go with what they already believe. "Of course birds' wings aren't designed--evolution explains them. Mostly." "Of course this horoscope matches my life by design. It looks designed... mostly." We don't have any rigorous accounting for if that "mostly" is enough, or if it's a crock; we don't have any rigorous accounting for if that "design" is enough or if it's an illusion. We have no way to compare the two--looking for a principled way to do so is a genuiine and good pursuit. To ignore such a valid question and simply go with prior belief is intellectually sloppy.
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As far as methods, it would take a whole book--actually three whole books--to outline their current best guess at a method, and overall observations. So I'll tell you what I'll do. I've give some of the basic observations as a teaser, and then just plunk down the technical desription as a teaser for those with the math/philosophy background.
The only attempt I know of at a philosophically rigorous attempt to clarify design inferences is found in William Dembski's "The Design Inference" and subsequent books. That's the method I'll describe.
His most basic observation is that, at the least, a design inference requires two things, which he calls "specification" and "complexity." Specification is a pattern to which the observation must conform. Complexity just means improbability. Something must be both improbable and meaningful to trigger a design inference. In the classic example, suppose we see Scrabble tiles arranged on a tabletop. If we see two tiles next to each other that spell "IT", that is specified--it's a meaningful word--but not complex. It doesn't trigger a design inference, because it could have easily come about by chance. If we see a set of tiles that spell "XPVWN AGON AWMD GNGPFING WK," that is complex without being specified. That exact sequence of tiles is improbable--it's unlikely we'll ever see it again--but it is meaningless. Again, no design inference. But if the tiles spell "THE DESCENT BULLETIN BOARD," that is both specified (it's meaningful on several levels) and complex (it's a lot of tiles). We assume, without a second thought, that someone arranged them that way. That is, we make a design inference.
Really, we approach design inferences with a pattern in hand--something like, "This is a sequence of prime numbers" or "That was the name of an internet forum I visit." This pattern has to be good in several ways. It has to be meaningful, it has to be simple, it has to be something we could come up with independantly (i.e., it's not "I see XNWGAPID in Scrabble tiles on the table.") Dembski rigorizes this a bit, by requiring that patterns for design inferences come from probabilistically independant side information, and that they be "not too difficult" for a person to formulate from that information.
We also approach design inferences with some knowledge about the world in which they happen. Really, we have some competing naturalistic explanations--different chance hypotheses that yield different probability measures. What we'd like, for a design inference to go through, is for an event to occur that matches a meaningful pattern--a pattern which is very unlikely under any of the relevant chance hypotheses. (And a pattern so unlikely that it's still unlikely to occur even given the number of chances the universes has had to achieve it.) These restrictions are rigorized into calculation of the probability of the image of the pattern under all of the relevant chance hypotheses, taking into account the available probabilistic resources.
[Begin super-technical section. Skim if you aren't comfortable arguing math with Lothar.
]
In its full-blown technical glory, a design inference requires a subject S, an event e in an event space E, a set of chance hypotheses H* with associated probability measures M*, a pattern D in a pattern space, a partial mapping D* from the pattern space onto the event space, some probabilisticaly independant side information I, a bounded complexity measure Phi that represents S's problem-solving ability, and probabilistic resources Omega. The probability of D*(D) under all M in M* must be "small" with respect to the probabilistic resources Omega. The pattern D must be possible for S to formulate under Phi from I. I must be independant of E under all M in M*.
[End super-technical section.]
Pandora, your objection's a good one: we can never be sure we've accounted for
all the possible natural causes of something. That's okay, though: the design inference is only about telling us what it's rational to believe, given what we know. It isn't a mathematical proof, it's an assessment of the available evidence. If what we know changes, our conclusions might change. So something that looks natural might later look designed when we learn new things about it, or vice versa. When you think about it, that's entirely natural.
As far as proof of this goes, Dembski's argument for the method is long, technical, subtle, ingenious... and flawed. (I found the hole in the proof, and furthermore I have a counterexample
). It still has some merit, though, in justifying some of the definitions and restrictions on design inferences. I won't begin to describe it here--it took me six months to absorb it, another three to find a counterexample, and three more to conclude the flaw was essential, not spurious. Suffice it to say, there's a lot of math and philosophy. An awful lot.
But there are some accessible criticisms of the method. The most common is that it's inapplicable to anything bigger than a toy problem. People both inside and outside of ID complain about that. Dembski himself tried to apply his method to the origin of the bacterial flagellum and failed BADLY--he wound up re-calculating the probability that the thing would assemble at random in one generation, and used some non-functional logic to try to make that mean something relevant. It was scandalously bad.
So for all of that work, ID really only has a few considerations and points out a few pitfalls. Its intuitive arguments remain the most appealing. I myself sort of watch curiously and hope they make progress, because I think they're asking a good question.
One thing's for sure--ID's far too young to be a rigorous position on origins. It's at best an intuitive one, though the intuition
is appealing (I again highly recommend Meyer's paper above to get up to speed on that.) Despite the fact that the argument's not as rigorous as it should be, it's a powerful one. I again point out that Anthony Flew credited it with changing his mind--so it's at least worth looking at.
But I myself am hestitant and skeptical about ID as an origins position, and though it has come the closest of any origins position to convincing me... I think it needs work. Others think it's garbage doomed to fail, still others think it's a scientific revolution waiting to happen. I guess time will tell.
