At 01:57 PM 8/29/00 +0100, Richard wrote:
[...]
RW:==
>I think the reason most evolutionists say that selection is not random is
>that, to most people, the word "random" means that all possible outcomes are
>equally probable. And selection events are not equiprobable. Fitter
>individuals are more likely to be selected. But a random variable is still
>random if it has a non-uniform probability distribution.
>
>Natural selection results from the different reproduction rates of different
>individuals and species. But these reproduction rates are influenced by
>random events as well as by biological fitness. Even the fittest gazelle in
>a herd may have the misfortune to fall prey to a lion through no fault of
>its own, and die without offspring, while its less fit neighbour lives to a
>ripe old age and has many. Whole species may be wiped out by a cometary
>impact.
OK, I think we will find some agreement here, though I might
say it differently. I believe the main reason for saying selection
is not random is to contrast it with mutation. To be clearer we
might want to add "with respect to". Mutation might be random
with respect to utility and it may not be random in some other
sense. Likewise, selection might be random in some ways,
but it is not random with respect to utility.
> >I think its also useful to point out once again that the randomness is with
> >respect
> >to utility.
>
>Agreed. The impact of a comet may be non-random with respect to astronomical
>considerations (at least if one considers a period which is too short for
>chaos theory to come into play), but is random with respect to the fitness
>of gazelles.
>
> >Even the mutation element of evolution is not random in the
> >statistical
> >sense of the word.
>
>Ah... so you disagree with Dawkins quote that you gave above. Good. The
>difference between us is a semantic one over the meaning of the word
>"random". At least we're each using the word consistently. But I think
>Dawkins is being inconsistent here. (Or maybe he's using "random" in a third
>sense, different from both of ours!)
Actually, I was reminded of this as I read that particular section of
Dawkins again. IOW, the point I made above is not in disagreement
with Dawkins. I guess it is probably hard to capture what he is saying
with such a short quote. I think his discussion of randomness wrt
evolution is very good and would encourage folks to read it.
As to Dawkins use of the word random, I believe he is very close to
my own views. What he says is very consistent with the algorithmic
view of randomness though he doesn't really use the type of terminology
I might expect from someone familiar with this view.
>Also, I'm confused by your use of "random in the statistical sense of the
>word." Have you been using "random" in two different senses? Please clarify.
I usually use random in the algorithmic sense. If I mean it in some other
way I'll usually try to qualify it as above.
> >Since there is a disagreement here on this basic point it will be useful to
> >define what
> >is meant by random. The definition I like best comes from algorithmic
> >information
> >theory and was developed largely by Chaitin whom I've mentioned before.
> >This definition
> >overcomes some difficulties (which I won't go into) with the definition
> >from probability
> >theory.
>
>Oh, please do go into them. I don't know what difficulties you're referring
>to, but perhaps they're central to this discussion.
A little on this below.
> >In fact, these difficulties were one of Chaitin's motivations for
> >pursuing this.
> >
> >I don't want to get bogged down in details, but basically randomness has to
>do
> >with patterns. If something has a pattern, then it is not random.
>
>I don't see what this has to do with the statistical notion of randomness.
>You seem to be simply defining random to mean unpatterned. In that case, I
>have to ask what you mean by a pattern, and what it has to do with
>probability theory.
>
>As far as I can see, a pattern is simply what we observe. We can argue about
>whether the pattern was produced by a random process or not, but then we're
>adopting my perspective of looking at the randomness of the process, rather
>than of the result. And random processes certainly can produce patterns.
>
>I don't know what Chaitin was referring to, but I suspect it was something
>to do with testing whether a particular sequence of digits was generated by
>a particular probability distribution, say a sequence of identical
>independently distributed random variables. In that case, again, we're
>talking about the randomness of the process, not of the result.
>
>I suppose you could take a frequentist approach and ask about the randomness
>of the end result by considering multiple trials and seeing whether they
>produce different results. Unfortunately, that's not practical in the case
>of evolution. But I think most evolutionists would agree that if we could
>start the evolutionary process all over again, we would not get exactly the
>same result. If they're right, then, in the frequentist sense, the outcome
>of evolution was random.
>
> >So, by your
> >own admission in your comments above, evolution is not random according
> >to this definition of randomness. Note also that an advantage this
> >definition is
> >that it is objective.
>
>Not unless you have an objective definition of "pattern"!
>
> >There is no talk of purpose, meaning etc. I could not
> >say,
> >for example, that evolution is not random, therefore it is purposeful.
> >Questions
> >like that cannot be dealt with objectively.
>
>There are actually three possibilities: a process can be deterministic,
>random or purposeful. If you take a deterministic view of free will, you
>might reduce that to two (eliminating purposeful), but I don't want to beg
>that question. I'm also simplifying, because a process may include a
>combination of these three elements. (And I've argued before that there's no
>such thing as a purely random process. All processes have some element of
>determinism, provided by the laws of physics.)
>
>Again, I'm back to talking about the process, not the end result. If you
>insist on talking about end results being random, without consideration of
>the processes which formed them, you're going to have to explain just what
>you mean.
Yes, I think I see the difficulty. What motivated Chaitin was exactly
this. He wanted an objective and intrinsic measure of randomness.
By intrinsic I mean determined by the sequence (or results) themselves
independent of the process that produced them. Due to potential
confusion some now say stochastic process instead of random
process.
Yes, pattern can be very subjective of course, so let me
back up. The key issue with algorithmic randomness
is compressibility. A string that cannot be compressed
is said to be random. Generally speaking, a pattern is
what one uses to compress the string. Generically, this
kind of agrees with the everyday notion of pattern, but
there may be exceptions. Humans seem particularly
good at "seeing" patterns which aren't really there. Likewise,
patterns in the sense we're speaking of here may not be
obvious at all.
You mention above there are three possibilities. Actually
from this point of view there is a continuum of possibilities,
however, purposeful is not included. Purpose is subjective,
it can't be measured. The reason for the continuum is that
the notion of randomness admits of degrees. Something
may be very nearly incompressible but not quite. One
can make this notion precise by introducing per cent
compressible. Something only 5% compressible is
nearly random. Something 95% compressible is very
ordered.
In my view, evolution fits on this scale towards the upper
end. It is not random but highly complex.
I don't know if this helps. I think our key difference is the
process versus result distinction.
Oh, I almost forgot to mention the "dilemma" which Chaitin
solved. This is usually described something like this. Suppose
you have the following two strings which supposedly represent
tosses of a fair coin. 1=heads, 2=tails:
(A) 0101010101010101010101010101010101010101010101010101010101010101
(B) 1110101010010010101001010011000111100111100110011111000011010011
Is either of the results more surprising than the other? From the point of view
of probability theory we cannot really say since the probability of any
specific
sequence is the same.
What we learn from the above considerations is that if a number is
defined to be random in view of the process by which the number is
produced, then an obviously ordered result such as the first sequence
above must be considered random since the random process of coin
flipping produces that result with a probability equal to that of any
other specific sequence. In the words of Gregory Chaitin "The conclusion
is singularly unhelpful in distinguishing the random from the orderly.
Clearly a more sensible definition of randomness is required, one that
does not contradict the intuitive concept of a 'patternless' number."
(Chaitin, G.J. (1975). "Randomness and Mathematical Proof," <Scientific
American>, 232 (May 1975):47-52.)
As might be expected from the above, the "more sensible definition
of randomness" is Chaitin's :).
> >RW:==
> >>It might help if you would clarify what your position is on intelligent
> >>agency. Do you think there has been intelligent direction in the
> >>process of evolution, or only in setting up the initial conditions? If you
> >>think there has been intelligent direction in the process of evolution,
> >>then I don't think you fully accept the theory of evolution.
> >
> >hmmm.... :). That this seems such an important issue indicates to me
> >that it is evolutionism of which you speak rather than the scientific
> >theory of evolution.
>
>Please clarify what you mean by evolutionism. Do you consider yourself a
>theistic evolutionist?
By evolutionism I generally mean a philosophy or worldview based on evolution.
A general feature is talk of lack of purpose meaning etc.
> >Anyway, I've discussed this point in the past. Let me just give a link
> >to the archives.
> >
> >http://www.calvin.edu/archive/evolution/200005/0236.html
>
>Strange... I don't recognize that post and I don't seem to have replied to
>it. I must have overlooked it. I certainly would like to reply to it. Would
>you like to resume that discussion?
Well, I'll try, time allowing and all that :).
>In the meantime, I note that one of the possibilities you were willing to
>consider is the following:
>
>"(3) The image of God has to do with soul and spirit, rather than body.
>
>"In this view, the physical body of man is not pre-ordained. Evolution
>proceeds
>until God finds a suitable result. He then breaths his spirit into the
>species
>he so chooses."
>
>So it seems you're prepared to consider the possibility that God did not
>intervene in the process of evolution (if we consider the addition of
>spirit--whatever that is--to be separate from evolution).
Yes, yes, I've been considering it a long time :). The basic problem though
is exactly what that means. My view is that God transcends time. The
options you presented earlier were God intervening or God setting initial
conditions. Both of these are temporal activities that I feel can never really
capture what God does. IOW I don't believe God intervenes in any usual
sense of the word nor do I believe he set the initial conditions in any usual
sense of the word. This is also why I feel this is all a theological issue
which science cannot address. Perhaps there are some gods that might
be dissected, but not the God who is. The God I believe in.
What I've been playing here is essentially a devil's advocate. I do not think
one can say (scientifically) whether evolution is used for God's purposes,
whether he directs the process etc. How could one know? Earlier you
mentioned contingencies. This is exactly the type thing a clever god could
use to direct evolution behind the scenes.
> >Your comment about fully accepting the theory of evolution reminded me
> >of a quote of Dembski that I saw on the asa listserve:
> >
> >"Not to put too fine a point on it, the Darwinian establishment views
> >theistic evolution as a weak-kneed sycophant that desperately wants the
> >respectability that comes with being a full-blooded Darwinist but refuses
>to
> >follow the logic of Darwinism through to the end. It takes courage to give
> >up the comforting belief that life has a purpose. It takes courage to live
> >without the consolation of an afterlife. Theistic evolutionists lack the
> >stomach to face the ultimate meaninglessness of life, and it is this
>failure
> >of courage that makes them contemptible in the eyes of full-blooded
> >Darwinists." William Dembski, in _Intelligent Design_, InterVarsity Press,
> >p. 112.
> >
> >Is this what you mean by fully accepting?
>
>What I mean is that the theory of evolution, as I understand it, is based on
>random, undirected variation and natural selection. I think Darwin wrote
>that, if he thought intelligent direction was needed at any point in the
>process of evolution, then he would consider the whole theory worthless.
>(I'm sorry I can't find the quote at the moment.)
>
>Dembski's point about "sycophants" and "respectability" is just the sort of
>propaganda that we expect from IDers. If anyone sees TEs in this light, it's
>IDers, like Phillip Johnson. Personally, I'm sure that the reason TEs accept
>the theory of evolution (in so far as they do) is because that's the way the
>evidence leads.
Thanks. Yes there is the evidence and all that :), but I personally
find the theology appealing as well. Were I ever to go back to the
ID position it would be a sacrifice in this sense.
>I do have my doubts about whether the TE position is tenable, but then I'm
>still struggling to understand what that position is.
For me it is a theological position.
> >It might be tempting to say that Dembski is misrepresenting his opponents.
> >Actually, I do not think he is. In his excellent book <Finding Darwin's
>God>,
> >Kenneth Miller devotes a chapter to this type of thing, "The God's of
> >Disbelief".
> >He sets up this chapter in the following way:
> >
> >"By and large, the critics of evolution are not cynical opportunists. They
> >aren't stupid, and they certainly understand how strong the scientific
> >evidence is against them. So, why do they oppose evolution with such
> >passion and persistence? I think I know, and as we shall see in the
> >next chapter, many of my scientific colleagues, so baffled at the strength
> >and depth of anti-evolution feelings in the U.S., would be surprised to
> >discover that they are themselves a large part of the reason why." --
>Miller
> >
> >Lest there is any confusion, Miller is a rather ardent Darwinist.
>
>I'm trying to avoid the term "Darwinist", since there's so much confusion
>about it (as seen in recent posts). I think I'll use the term "mainstream
>evolutionary theorist" in future, or some variation on that.
ahhhh. Get MET, it pays :). I added the part about Miller being
an ardent Darwinist only because it seems rather unusual, for
me anyway, to find TE's who are also gung ho about Darwinism.
> >Anyway, I think Miller's criticism is fair and appropriate.
>
>It may be that people like me, who find it impossible to reconcile the
>theory of evolution with theistic direction of evolution, make it more
>difficult for some people to accept the TOE. But I guess that's the price of
>honestly saying what we really think.
And I'm not saying you shouldn't be honest in saying just what
you think. I'm all for that. The problem is when these type things
are presented as scientific conclusions rather than as the opinions
of scientists. Oh, and someone merely saying they have a hard
time seeing theistic direction. This is not the type thing I have in
mind as being problematic. It is instead the blatant and insulting
anti-religious sentiment that you see from some folks. You, I don't
believe, are guilty of such things. But I kind of like being blunt
myself sometimes. That's why I asked you about this so directly.
> >How is it that my position differs from someone like Phil Johnson? Phil
>wants
> >to drive a wedge between science and naturalistic philosophy. I'm all for
>this.
> >We would differ in that I would prefer the wedge to be indiscriminate. I
>would
> >want the wedge to separate science from all philosophy and theology as
>well.
> >Further, I think we already have a good wedge for this purpose,
>methodological
> >naturalism. I believe this wedge to be working pretty well in science
> >itself, where
> >it sometimes gets put aside is in the presentation of science to the
>public.
>
>I don't think science can be entirely divorced from philosophy, because
>science is itself based on a philosophy. That's why we talk about the
>"philosophy of science".
Yes, this is true. I'm a methodological naturalist (MN). As such, it
would be inconsistent to try to rule out other approaches since the
instruments and techniques of science do not themselves demand
MN. What I am critical of is not philosophizing about how science
is done but rather philosophizing about what it means. Opinions
about what it means should be carefully distinguished from the
actual results.
>And I've yet to see any good reason why divine intervention should be given
>a privileged (or underprivileged) position, placing it outside the bounds of
>science.
I tend to argue rather forcefully against including divine intervention as
an explanatory device in science. I take this as my God given right :).
This is not to say that these should be excluded _a-priori_. But all
approaches are judged by their contribution. One can make arguments
showing, I believe, that such approaches make no contribution. So,
to me, they fail right away. Again, anyone has the right to try out
such notions, I also have the right to criticize them at this most basic
level. I guess the problem is that they get dismissed at such a basic
level that it might seem to some that they are just being dismissed
_a-priori_.
[...]
phew, it's hard to find time for such demanding replies (i.e. those
requiring that I think :) But before I quit I would like to go
back for a moment to what started this discussion:
Bertvan wrote:
#"[...] On the other hand, if the variations were actually random,
#without meaning purpose, plan, or design, surely they would outnumber any
#occasional advantageous variation so as to completely drown it out."
to which I replied:
#As has been noted many times, random in this context does not
#mean "without meaning purpose, plan, or design". Any "meaning
#purpose, plan, or design" is not detectable with scientific instruments.
#For example, in information theory one measures the quantity of
#information in a message irrespective of what it means. One would
#not conclude from this that messages have no meaning. Also,
#consider the engineer that designs complicated mechanisms by mimicking
#Darwinism, i.e. by random variations coupled with a selection criteria.
#Would the random variations be "without meaning purpose, plan, or
#design" in this case?
Despite our lengthy discussion, I am even more committed to the
accuracy of what I wrote. Let me ask you this. How would you
measure the purpose of an outcome or process? What would the
units be? Purpose is subjective. As I learn more about evolution
I am more and more impressed by the grandeur (to quote Darwin)
of it all. All the talk of chance and contingencies do not diminish
this at all. But this is very personal. I can understand people of
different persuasions seeing something entirely different. That's
fine by me. What we're talking about is a metaphysical view or
interpretation of science and not science itself.
Brian Harper
Mechanical Engineering
Ohio State University
"Baby, I was born bawlin' and
I'm gonna bawl the rest of my life."
-- Fats Waller
This archive was generated by hypermail 2b29 : Tue Sep 05 2000 - 21:19:58 EDT