In the above
video William Dembski gives us a digest of his mathematical work and what it
means for evolution. It attracts the notice of Joe Felsenstein on Panda’s thumb and also PZ Myers who quotes Felsenstein. Myers
seems too jaded and tired to engage the video properly and so hands the issue
over to Felsenstein after declaring Dembski as “still wrong”.
Felsentein does
give Dembski a fair hearing and that’s what Dembski deserves: In Dembski we are
not taking about the abrasive and judgmental fundamentalist lunatic fringe: In
my view Dembski has done some worthy work, work that deserves proper scrutiny. Moreover,
Dembski, to me at least, always comes over as a nice reasonable guy who is not
going to threaten anyone with divine judgment if they don’t agree with him.
Unfortunately the creation question has been blighted by fundamentalist crank science
and the resultant polarisation hasn’t helped the cause of evangelical
moderates like Dembski.
Between them
Dembski and Felsenstein both provide some great food for thought, a veritable
intellectual feast in fact. However, my overall assessment of the situation is
that Dembski and Felsenstein are talking past one another: In the final analysis
Dembski is talking about mathematical generalities and Felsentein more about
biological specifics (as one might expect from, respectively, a mathematician
and biologist). As I have said before on this blog, Dembski’s mathematical
points are irrefutable, but they are very general and they don’t directly address
the specifics raised by Felsenstein. But the social backdrop is that the Intelligent
Design vs. atheism debate has set up such a strong polarizing field that even
someone like Dembski will be demonized.
Dembki’s Video:
Twenty seven
minutes into the video Dembski throws up a quote by Stuart Kaufamnn which
includes the following statement:
Where did those well-wrought fitness landscapes come
from such that evolution manages to produce the fancy stuff around us? No one knows.
Yes, the
giveness of the requisite fitness landscape is a critical and enigmatic feature
of evolution: The fitness landscape is the equivalent of my connected sets of stable organisms : Viz:
for evolution to work the class of stable structures must form a continuously
connected set in configuration space…. but not only that, the number of ways
these structures can be slightly altered must be limited enough for the jump to
the next stable structure to not be swamped by the number of possible changes
that destabilize the structure. Taken together these two conditions of connectedness
and limited “modification linkage", allow conventional evolution to diffuse
through the class of organic structures.* Let me just say in advance that over
the course of several years I have toyed with the idea of the kind of fitness
landscape that would facilitate evolution, but I now doubt that the right landscape
has a mathematical existence – I will say more about this in due time.
It is the
rightness of the fitness landscape that is the essential abstract structure
that would have to guide the standard evolutionary search. If we are to arrive at a working
version of evolution we must first get this structure right; or as Dembski
expresses in computational terms we must search for the search. The
self-maintaining structures of biology are extremely rare in the huge space of
absolute possibility; to locate these structures in relatively few algorithmic
steps implies an algorithmic starting point that is itself of an extreme rarity (and by
implication, also of extreme improbability); in terms of absolute possibilities
the smooth fitness landscapes that would render evolution viable are themselves
extremely rare beasts. On this point Dembski is irrefutable; in fact he quotes
Paul Nelson who says that evolutionary theory fills one hole by digging another
(31:20). Moreover, as Dembski hints, people seem unable to see this enigmatic
entity of the fitness landscape. This is probably because it is an abstract
object which exists in mathematical space as a background controlling structure
and this is not easily seen or imagined. In as much as the requisite “fitness landscape”
is itself a very rare structure Demsbki’s mathematical point about the projection
of one seeming improbable outcome onto another is - I say it again - irrefutable:
(See also here, here and here)
Dembski doesn't
just provide food for thought for evolutionists; he also says something that
ought to pique the interest of the North American dualist ID movement. At 32:30
he says this
So many ID arguments look for discontinuity in the evolutionary
process (as opposed to the chance of finding a result given the method of
search )…[they] look for evidence for discontinuity.
But I’m going to give you evolution and common ancestry
but what I’m interested in is the probability of success using this method of
search
At this stage
Dembski is neither attacking evolution nor common ancestry; rather he is
concerned with the initial “information” required to get standard evolution to
work as a process. In the above quote Dembski contrasts his approach with the dualist IDists who are enthralled by
the thought of “magical” looking discontinuities existing in natural history.
However, I’m not sure whether Dembski is just putting on his evolutionary cap
for the sake of the argument and neither am I sure just how far he might
support evolution as a process that has been “front loaded” with the requisite
fitness landscape information in order for it to work (See also this blog post of mine where I comment
on another video in which Dembksi says something very similar). But I’m
gratified that Dembski has implied that his work does not necessarily support
those “God of the gaps” ID arguments which very much hang on discontinuities in natural history. Dembski may or may not
support evolution but what he has done is that he has made clear just how mathematically “front loaded” the
cosmos must be for evolution to work.
By way of
conclusion (at 49:20 and 50:18) Dembski
says this:
Darwinian search works because its carefully fine-tuned
to work …… Darwinism is the teleological search for teleological systems.
My comments, reservations and trial conclusions
Dembski’s
theorems have their origins in a fact that is agreeably intuitive; namely, that
self-maintaining, self-replicating structures as a class form a negligibly
minute proportion of the huge space of possibility. When these kinds of
proportions are expressed in terms of ratios (e.g. such as the size of the
class of organic configurations to the total mathematically possible configurations
or the organic class to the physically constrained possibilities) then this will
give us probabilities. In fact Dembski’s Conservation of Information (CoI), a
theorem that he introduces in his video in probabilistic terms, can be illustrated with a poor man’s mathematically
impressionistic proof as follows (But see Dembski for the McCoy version):
Let T be the total conceivable possibilities
available to configuration space and L
be the number of organic life forms in that space. Thus, assuming
equal-a-priori probabilities then the probability of life given T is,
p = Prob (Life | T) =
L/T
Now let us
assume that a physical constraint is applied to the space of possibility which reduces
the physical possibilities down to C and that we know living structures are
a subset in C. The probability of finding life given this
constraint then becomes
q = Prob (Life | Constraint) = L/C
Let us make the
not unreasonable assumption that the probability of finding the constraint
class is proportional to its size C given T. It follows then:
Prob
(Constraint | T) = C/T = L/T x C/L
= p/q
That is, the
probability of finding the constraint class is equal to the ratio of p/q. This is not a rigorous proof** by any
means but it conveys the idea of CoI in broad brush terms: To increase the
probability of finding life to the value q
( > p) we first need to find the constraint. But the above equation tells us that the probability of
finding this constraint is proportional to the extremely small value of p. Therefore if we want a large value of
q then the probability of finding the
constraint is going to be very small; in short the low probability of finding
what we want (i.e. life) cannot be removed. According to Dembski the major computational
problem of finding life must be effectively solved before we do any
“evolving”.
Of course, in
the real world the laws of physics provide the kind of constraint which reduces
the search space, but it is not at all clear whether or not these laws imply a sufficiently
connected and low linkage set of self-sustaining structures to give standard
evolution a realistic chance of finding life. If the known laws of physics do facilitate
standard evolution then the cosmos has been effectively “front loaded” with
information in the form of the right physical regime. At one time I favored
this possibility but now I have my doubts – my reasons are to do with the
nature of quantum mechanics; it is both a constraint and potentially a way of making huge numbers of computational steps; if
this potential is used then there is no need to front load the search with q (See my Melencoli I series).
Under quantum circumstances information, in the way Dembski has presented it, is not necessarily conserved. Conservation of Information
only applies to small space, short time algorithmics where we envisage
computation very much limited by Dembski’s computational upper bound. Keeping within that
bound we find that either the result sought for is highly improbable or the
search used to find it successfully is
improbable; improbability ( = information) swaps from one to the other and we
can’t get rid of it; it almost seems to have a conserved property, hence Dembski's CoI. But if that upper bound is taken away it’s a bit like saying
that the Cosmos has unlimited energy available: If the processing potential of Quantum Mechanics is accessible, then the upper bound is removed: Without that upper bound huge computational resources
turn improbabilities into high probabilities and information seems to just come
out of the “vacuum” so to speak. (My pro tem conclusion is that the cosmos is immanent intelligence in action, an intelligence we see only at the low level, much like looking at the neurons of the human brain.)
In the next part
of this series I will look at Joe Felsenstein’s reaction to Dembski. I’m not
giving away much in saying that his basic argument is that the laws of physics do provide sufficient front loading to
make the search for life a realistic option. In my view he is both right and
wrong; right because, yes, the laws of physics flow out of quantum mechanics
and it is quantum mechanics that does the trick. But he is wrong in that
physics hasn't been front loaded in the way Dembski’s work suggests. Rather, if
quantum mechanics is the search engine it has such huge processing potential that
a smooth fitness landscape would not needed to be front loaded into the cosmos. However, I’m not pushing this as a likely idea,
but rather as an avenue to be explored; and yes it could be a dead end.
Footnotes
* Complicating
this concept of the fitness landscape is the fact that an organic regime
becomes a very important part of that landscape itself and therefore a feedback
occurs which will mean that evolution is non-linear.
** This proof is based on the assumption that the cases in favour of life are a subset of the search cases. However, in general the two could simply intersect in which case we find:
Prob (Constraint | T) < p/q
** This proof is based on the assumption that the cases in favour of life are a subset of the search cases. However, in general the two could simply intersect in which case we find:
Prob (Constraint | T) < p/q
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