Richard Wein wrote:
RW>Wesley, since you've raised this subject again, I'd like to
RW>reiterate my view that CSI, as Dembski defines it, has not
RW>been shown to exist in nature.
RW>Since we last discussed the subject, I've had it confirmed
RW>to me that Dembski, in his book "Intelligent Design",
RW>defines the test for CSI as:
RW> -log2 P(E) > 500
RW>where E is a specified event. (I haven't read the book
RW>myself, but this is basically the same as the definition
RW>Dembski gives in an on-line article.)
I just got a copy of this book, and I would agree that much of
the work can be seen in Dembski's on-line articles, modulo a
few editing changes. (Expect more on that later.) But that
is not the test for CSI. At best, that is a description of
Dembski's universal small probability bound. CSI is tested as
the conjunction of complexity and specification.
RW>This means that the test for CSI is the same as the test
RW>for design as defined in his earlier book "The Design
RW>Inference", namely:
RW> P(E) < 1/2 X 10^150
Not quite. TDI's formulation of the universal small
probability bound is better put as
P(E|H) < 1/2 X 10^-150
See pages 203-209 of TDI.
The conditional probability is, IMO, significant.
RW>But no-one to my knowledge has ever succeeded in showing
RW>that the probability of a specified event in nature is this
RW>small.
A 100-city TSP solution meets the criterion of the universal
small probability bound. If by "nature" Richard is referring
to biological events exclusive of human action, then we at
least have Dembski's assurance in "ID" that the bacterial
flagellum exceeds this value. But I would agree that no
detailed probability calculation demonstrates this.
RW>I've seen some calculations by IDers which claim to
RW>calculate the probability, for example, of a given protein
RW>forming from a number of amino acids. But they assume that
RW>the amino acids are selected as i.i.d. (identical
RW>independently distributed) random variables. Of course,
RW>this assumption is totally unrealistic, because evolution
RW>by random mutation and natural selection would not produce
RW>such a probability distribution (the amino acids are *not*
RW>independent).
This is where I see the conditional probability used in TDI
come in. We compute the complexity of an event on the basis
of how improbable the event is if it were due to chance.
This does not mean that we actually believe it to be due to
chance, or that we consider the chance hypothesis sufficient
to the task. But like other forms of statistical inference,
chance gives us a null hypothesis to perhaps reject.
RW>So the demand we should be making of Dembski is not "show
RW>that natural selection can't produce CSI", but "show that
RW>CSI actually exists in nature".
I think that CSI as a property is not that remarkable. But I
agree that someone who urges others to "do the calculation"
might break loose with a few examples that show *all* the
work, just to get everybody started. Preferably, one or more
completely worked examples for each of the possible
termination nodes in Dembski's Explanatory Filter would be
provided. At least one set of examples should be taken from
biological science.
Wesley
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