Re: Beliefs and Theories
- From: Guy A Hoelzer <hoelzer@xxxxxxx>
- Date: Thu, 21 Jun 2007 16:44:12 -0400 (EDT)
in article f55954$2eea$1@xxxxxxxxxxxxxxxxxxx, John W Edser at
edser@xxxxxxxxxxxxxx wrote on 6/17/07 11:36 PM:
Guy A Hoelzer <hoelzer@xxxxxxx> wrote:-
I separate beliefs from theories. I wouldn't call an idea a belief
unless or until a critical view of the idea has been abandoned. In
contrast, I wouldn't call an idea a theory unless it is deeply
embedded
in critical thinking.
JE:-
Please provide an example.
Kimura's Neutral Theory of Molecular Evolution certainly qualifies as a
theory in my book. ALL notions of supernatural action are based on
belief.
JE:-
My apologies for such a late response. My understanding of Kimura's
Neutral Theory of Molecular Evolution is this view remains based on the
assumption that a random process can provide evolution in its own right,
i.e. a non random process is not also required. While it is mathematically
true that just a random process acting alone can provide change, to
constitute a theory of science such a process must exist within a non
random process so that it does not constitute the entire theory . In
evolutionary theory the non random process can only be natural selection
because no other has been proposed. In other words, any theory of
evolution via heritable random change can only be regarded as a form of
heritable variation on which non random natural selection can act. This
restricts all random events to constitute just a small part of any
evolutionary _theory_. Random processes supposed in isolation remain
"supernatural" because they assume that an empirical event is not caused
by an predictable law of nature. This being the case, I find your example
contradictory to your proposed way of separating of a belief from a
theory. If you do not agree, how do you propose to explain random events
in a scientific way?
I didn't claim that the Neutral Theory of Molecular Evolution was the
Theory of Everything, or the complete theory of evolution. I claimed it
was a theory as opposed to a belief. I have no problem with theories
invoking stochastic inputs, so I do not feel obliged to explain "random
events" to defend my characterization of Kimura's theory as a theory.
JE:-
I don't think that I had claimed that you had claimed "that the Neutral
Theory of Molecular Evolution was the Theory of Everything" so I don't see
the point of this comment.
A theory of everything would not include random inputs because all inputs
would be fully understood within a theory of everything.
JE:-
I would agree. A _complete_ theory of how this universe works cannot leave
anything to chance otherwise it remains incomplete. However, this reduces
chance events to only a constitute mathematically based beliefs. Would you
agree that any proposed theory of evolution which remains entirely a random
process cannot be anything other than a belief and not a theory?
I do not think " this reduces chance events to only a constitute
mathematically based beliefs." I take randomness as both real and
subjective. A pattern is in fact random to an observer when the observer
has no basis with which to extract information from the input. To an
observer, static noise is what it is. The same input may be melodic to
another kind of observer. I am using the term "observer" here to mean any
dissipative system impinged by the input, not merely limited to humans. In
other words, input that informs (influences) one kind of system may be
uninformative (not influential) to another. Thus, I don't see assumptions
of randomness as implying beliefs, although beliefs probably mold
sensitivity to inputs and which inputs appear to be informative. So I guess
I would not agree with your suggestion.
You appear to have claimed that the Neutral Theory of Molecular Evolution
constitutes a theory in its own right, i.e. Neutral Theory remains
independent of any non random process. Is this correct? I simply challenged
this position for the reasons given.
Well -- I do claim that the Neutral Theory of Molecular Evolution is a theory
in its own right, but I do not claim that neutral molecular evolution is
independent of any non-random processes.
JE:-
What is the non random process on which Neutral Theory remains dependent?
Neutral theory depends critically on assumed molecular mechanisms of
replication and constraints on fluctuations of population size. There are
probably more, but they aren't coming to mind at the moment. One thing I
like about the neutral theory is that it seems to rely on a very small set
of non-random process assumptions.
Such independence is not a factor in my understanding of what constitutes a
theory (see my understanding of what a theory is at the beginning of this
thread). Maybe I don't understand your point here.
JE:-
Are you arguing that probability represents a theory of science in its own
right?
No; although I have no problem with scientific theories incorporating
probabilistic elements.
If Neutral Theory constitutes a "theory as opposed to a belief " but is NOT
"the complete theory of evolution" what then is the complete theory and what
relationship does neutral theory have to it?
First let me say that I see all theories of particular phenomena are
artificially severed from all other phenomena.
[snip]
With that in mind, I think anywhere you want to cut off the theory of
evolution from the rest would be a bit arbitrary. I am certainly happy to
combine neutral theory with selection theory as a step toward a fuller theory
of evolution.
JE:-
I am not attempting to "cut off the theory of evolution from the rest ".
Well, if you understood my argument above you would see that in my view all
theories, other than a theory of everything, must in principle be "cut off
from the rest."
All am asking is how you join the random process of probability to the non
random process of natural selection within the one same, evolutionary theory.
I'm not sure how to respond to this. It is quite common for scientific
theories to combine stochastic elements with deterministic influences. It
is so alien to my way of thinking that this would create conceptual problems
that I can't tell what you are looking for.
Random processes have always constituted an inseparable part of evolutionary
theory. Darwin and Wallace proposed that their non random process of natural
selection acted on ubiquitous random heritable variation in order to provide
evolution. Because of this, historically, evolution has always been argued
to constitute a _non random directional change_ and not just a random
change.
Here you seem to accept a combination of random and non-random factors in
evolutionary theory.
My understanding (please correct me if I am wrong) is that Neutral
theory deleted this critical historical difference, i.e. the difference
between ubiquitous random heritable variation and any evolution produced
from it via the non random process of natural selection acting on it.
You have confounded the distinction between variation (differences among
members of a set) and evolution (changes in the composition of a set) by
limiting evolution to changes caused by natural selection. Neutral theory
does distinguish between variation and evolution. Further, I think you
misunderstand the description of neutral theory as a random process,
although it does not include natural selection. Neutral theory does depend
on mechanism and constraints as I described above. If it didn't, it would
not give rise to testable predictions which, of course, it does.
Traditionally, evolutionary theory disallowed heritable random changes to
constitute evolution in their own right but Neutral Theory apprears to allow
this providing a starkly differenent approach. Is this understanding
correct?
Both theories allow mutation to be represented as random, heritable changes
in genomes. A very narrow Darwinian view might ignore drift within
populations, and a strict neutral theory view ignores the possible impact of
positive selection. The data overwhelmingly support the validity of neutral
theory at the molecular level, IMHO, if you wanted to have these extreme
versions of the theories compete empirically. I don't think it is even
close to clear yet how the two extremes would do at the organismal phenotype
level. More importantly, as I wrote earlier, I think you are posing these
extreme versions of the theories as a false dichotomy when considering a
general theory of evolution. There is no reason to think that the process
of evolution must work through either drift or selection alone.
While I agree that non random processes can invoke stochastic inputs (and
outputs) random processes acting in isolation to any non random processes
cannot constitute a theory of anything, just a belief which remains
mathematically based. This is because such a random process has no
scientific basic, i.e. it is proposed to be acting outside of any known law
of nature.
I don't see it that way. Neutral theory is entirely mechanistic
(constrained by the laws of nature), given stochastic inputs.
JE;-
The above appears to me to contradict what you wrote: "A theory of
everything would not include random inputs because all inputs would be fully
understood within a theory of everything." This means to me that chance
events cannot be constrained by laws of nature _because_ they are chance
events. If they were so constrained within the theory they could not be
chance events. Is this understanding correct?
In my view, that would be correct for a theory of everything, but not of
theories about particular phenomena, like evolution. String theory, for
example, is sometimes touted as a possible theory of everything; but AFAIK
string theory assumes that the strings vibrate without explaining why they
do so. In my view, this would eliminate string theory as a theory of
everything.
Guy
.
- References:
- Beliefs and Theories
- From: John W Edser
- Beliefs and Theories
- Prev by Date: Re: Cnidaria versus ctenophora
- Next by Date: Re: Flying non-chordates?
- Previous by thread: Beliefs and Theories
- Next by thread: Re: Beliefs and Theories
- Index(es):
Relevant Pages
|
