Re: Behaviorism vs. evolutionary psychology

On Jul 12, 2:28 am, Don Geddis <d...@xxxxxxxxxx> wrote:

DG:
But the _mechanism_ for the actual appearance of phenotypes
is: mutation + natural selection. Agreed, those two won't
tell you where a species will end up; it only tells you that
IF there is a possible solution in the universe, evolution
may be able to find it. But it offers no guides as to what\
the solution will be.

JC:
And how is that different from trial and error which
quickly falls victim to the combinational explosion?

I would avoid the anthropomorphication of evolution as being
able to find things. What we have is a process we call
evolution for the obvious reason it evolves. Evolution
doesn't do anything it is a description of a process the
mechanism of which are to be found out.

Mutation and natural selection will not tell you where
the species will end up but an understanding of the
evolving components might tell you where they will not
end up. For example toss a six sided dice as often as
you like you will not get a seven. I am suggesting such
constraints exist in nature and explain why there wasn't
this combinational explosion.

JC:
Evolution doesn't explain why or how these molecules or
laws are primed to evolve. What basic structures can come
into existence, by chance, to be selected in stages and
that these stages in turn have the right stuff to produce
more complex structures, by chance, which in turn can be
selected.

DG:
I'm not sure how much of an explanation you're looking for.
The first question is whether you can ever have a self-
reproducing molecule. DNA basically works, as do some
crystals.

Once you get to a level of a single-cell with DNA which can
replicate, the rest of life is pretty straightforward, don't
you think? I'm not sure where your big question is.
Are you most concerned:

1. How the universe gets from dead rocks to the first reproducing
organic molecules ("abiogenesis");
2. How single molecules turn into cells;
3. How single cells turn into the huge variety of complex life
forms that we observe on Earth today ("evolution").

There are explanations for each of these. Evolution is mostly
about #3. Your comments seem to suggest concern about other areas,
but I'm not quite sure which.


JC:
Each area is a step to be taken. A combination to be made.
It doesn't take too many variables to send the number of
possible combinations through the roof. So I am suggesting
that maybe each step is highly likely as a result of things
being the way they are. Why they are the way they are is
not explained. It is just good luck that matter happens to
have the right stuff.

I am suggesting that not just anything can evolve even if
it could form complex structures (say by human design) simply
because the parts are not capable of building themselves up
in working stages by chance alone in a sufficiently short time
span or the even if they form a configuration that they might
not have what it takes to hold that configuration.


JC:
Take reinforcement learning and the combinational explosion.
In theory trial and error should, given enough time, bring
about any pattern to be selected. But in fact the Universe
will not be around long enough for that to happen. Somehow
there are constraints in these systems that mean that they
can, within a reasonable time limit, produce the right
patterns to actually be selected.


DG:
Are you suggesting ("somehow there are constraints") that it's
a hard, unsolved problem, how evolution produced life in as
short a time (a few billion years) as it appears to have taken?
That the search space is too big, and there wasn't enough time?

Because that's not the situation. Geologic time, plus the rate
of DNA mutations, plus how genotypes get expressed as phenotypes,
is all sufficient to make the evolution story hang together.


If you mean something more basic, like that Earth happens to
have liquid water, or that the six (?) fundamental constants
of physics just happen to allow stable matter, etc. That's
a somewhat more difficult philosophical puzzle (but not
without proposed solutions), and you may want to explore the
Anthropic Principle:

http://en.wikipedia.org/wiki/Anthropic_principle

JC:
Essentially yes I am talking about the fundamental constraints
of physics, but not so much why they exist but rather understanding
how they are involved in making evolution possible. I am suggesting
they play an essential part in reducing the number of possible
mutations to be selected from.

That there was sufficient time and that molecules have the right
stuff to evolve into more complex forms via chance and natural
selection is a matter of observation not one of understanding at
this stage what is it about molecules that make this possible.

Mutation and natural selection are not in themselves sufficient to
explain evolution for that would assume anything can evolve providing
it can mutate and there is some selective force.

Take Dawkin's biomorphs. They can evolve, up to the point that they
have what it takes, which isn't very far at all. Their evolution is
form not function for example. Even if we built some mechanical
"molecules" which could interact via attraction/repulsion and energy
storage and exchange it wouldn't mean they had the right stuff to
evolve very far, if at all, because we don't know what the right
stuff is at this stage.

JC:
The constraints make it possible. They deliver possible things to be
selected within a reasonable time limit. That is not to be found in the
mutation or selection process.

DG:
I can't really make sense of this, unless you're referring to one of
the
things I described above. Perhaps you can give me a concrete
example.
What is a specific constraint you have in mind, that is not mutation
or
selection, yet allows complex life to evolve ("within a reasonable
time"
instead of taking longer than the age of the universe)?

JC:
If I knew what those constraints were I would be a clever fellow
indeed. For example the shape of a protein molecule is controlled
by more than its genetic code [ref Life's Other Secrets].

Without the right stuff, the right physical laws, there is no
complete understanding of how things evolved. Mutation and selection
don't explain how the possibilities were possible and that they
were possible to form in a given time limit with a given number of
mutations to select from.

Once when reading about this stuff I thought it would be neat to
make my own 2D binary folding "proteins". Take a strip of paper
and stick button magnets along it with different combinations of
North and South poles.

N-S-N-N-N-S-N-S-S

The paper allows them to bend between the rigid magnets.

Feed a strip held flat within a constraint and watch it fold
up as it comes out of the constraint.

I wrote a simple program that did something similar. Like Dawkins
biomorphs I could select "proteins" that folded up in shapes I liked
and mutate them a little bit and with that process "evolve" them to
shapes I liked. Of course they don't have the "right stuff" to ever
do anything great, the purpose was to get a feel for the problem.

Another example was the Beast in the passage problem posed by Curt.
Alternating food at either end of the passage. The beast could step
left or right. It had to choose the right sequence of steps to get
food and then have the ability to flip that sequence to move to the
other end of the passage.

Now it is easy enough to generate random sequences of steps which
in theory will one day find the food. But the longer the passage
the longer it will take. And a 20 step passage is a long passage
in this case. But let's say it has a constraint. If it takes
a step to the left and tends to take a lot of steps to the left.
Suddenly this constraint (non random factor) makes it possible to
solve the problem very quickly. It happens to be the constraint
you want. I am suggesting that nature is full of such convenient
constraints otherwise we could not have evolved the complexity
in the time given.

With proteins for example I am told there are many amino acid
combinations that will produce the same functionality. Whew!
That's lucky. Imagine how long it would take to mutate the right
sequence of thousands of amino acids if only one sequence was
possible or that they weren't made out of simpler but useful
sequences that preceded them?

JC:
The idea of reinforcement is the easy part. Natural selection
of mutations is the easy part. That those mutations are ever
worth selecting is the hard part to explain.

DG:
So you have a bunch of fish in the ocean, and their DNA slowly
mutates, and one begins to develop the ability to extract oxygen
from air instead of only from water (the beginnings of a lung
instead of a gill).

And your question is, how did any mutation to DNA ever result
in a proto-lung? And what answer do you give (different from
mutation + natural selection)?


JC:
Mutation is the "shaking the bits about" and natural selection
is the forces acting on those parts. An important constraint
is the ability to hold together the parts. That is what a magnetic
button has over a coin. It is not however sufficient. I am talking
about what is sufficient, what is required, for things to evolve
into ever more complex things by shaking the parts?

DG:
Are you getting at how genotypes (DNA) turn into phenotypes
(the large-scale appearance of an individual organism)? It's
pretty cool, and pretty complex, but is it really as big a
mystery as you seem to be suggesting?

JC:
Darwin really only showed that if parts could come together
they could be selected by forces that started pulling them
apart. Each stage would become more resistant to being
pulled apart (become selected by the destructive forces).

But this doesn't explain why it was possible in the first
place only that it must have been possible and being possible
would happen as a result of this selective process.

Things that are too stable and cannot be pulled apart will cease
to evolve (like a column of magnetic buttons). Things that are
too unstable and easily pulled apart will cease to evolve (like
a column of coins). It is the survivors along the edge of chaos
that evolve. They have the right stuff to hold themselves together
against the forces pulling them apart. They have the right stuff
to evolve into more dynamic stable systems resisting destruction.

One observation is that living things consume energy. What other
way can they resist the energies pulling them apart except with
energies utilized to hold them together?

Actually life has honed a fine balance between static and dynamic
structures via natural selection. And it has honed a fine balance
between mutation (so as to keep evolving) and stability against
mutation (so it doesn't fall to bits before it reproduces).

The other important element is that the environment includes other
evolving systems competing for the same resources. Thus we cannot
find the precursors of life as they were long ago wiped out by
the ever increasing complex systems that exceeded them. Should they
accidentally occur again (and maybe this happens all the time) they
would quickly be pulled apart by complex systems for their
components.

I see an analogy here with more complex social systems wiping out
less complex social systems. Simple societies can no longer compete
with complex societies for the available resources.


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