Posted by
Steve Smith on
URL: http://friam.383.s1.nabble.com/Was-human-nature-now-EvoDevo-tp3129527p3130325.html
Nic
k
Sorry. Misspoke. Don't
really make a distinction between human nature and the human
condition. Each is a creation of the other. they are dialectically
intertwined.... or whatever. So, you cant disagree with me on that
point any more.
Ah, but it is Human Nature *and* the Human Condition to disagree (for
fun and profit).
So, let's take this occasion
to transition to a different topic ... development.
Embryological models then...?
And I have to say, I still
don't quite "get it" But I think I am beginning to understand why ...
the metaphors they use are bad. Nobody has come up with a good
metaphor to come up with how we now know development to work.
Metaphors are like (to use a Simile) using piecewise linear (or more
apt for several reasons, piecewise sigmoids) curves to fit an arbitrary
1-D Function. Each piece can be pretty good "locally" but begin with,
but to stretch the application to far leads to disaster... thus the
"piecewise". Depending on the specific parameters of your linear (or
sigmoidal) fit, there are regions where more than one parametric model
(or metaphorical target domain) fit equally well and it only matters
which one you choose if you know which direction you are headed away
from the region of interest.
How do we get pluris
e uno?
Eh? All are One? One are One? We are all one? All one vs Alone?
The stunning discovery of the
last 25 years is how widely and in what detail sequences of genes are
similar among animals of widely different form. The metaphor they use
is of a genetic tool kit. Even tho organisms have many different
genes, they all share an essential toolkit. Carroll actually depicts
a little toolbox with cubbies in for the "tools". The DNA sequences
in this basic, shared tool kit are often similar down to the last
base. So even though planaria, bees, octopi, and humans have wildly
different eyes, the making of eyes in all of these species is dependent
upon a shared sequence of genes that generate a shared bunch of
proteins.
Actually I believe that eyes are the favorite example of multiple,
parallel (and sometimes convergent) evolution. That is not to say
that they don't share some of the same basic proteins, but that their
higher level structure (and coding) was (apparently) arrived at
independently. I think this might be more like noticing that many
"stone age" cultures use "stone", "plant materials", and "animal
products" for the basis of their technology. The fact that around the
world that many different cultures *knapped* stone and then lashed it
onto sticks to make spears and arrows and then made atlatls and bows to
hurl these missiles, seems more like the situation of
re-invention/discovery of eyeballness across many genera.
...
what would be GOOD metaphor
to encapsulate this process? Remember, we have stipulated here
repeatedly that all metaphors are faulted and that a GOOD metaphor is
one whose faults do not encourage defunct notions of what is going on.
So, for instance, in matters of development, a GOOD metaphor should
scrupulously avoid any implication of intelligence in its description
of what these "organizing" proteins are doing.
So... I've already used my simile of "piecewise curve fitting" to
describe how (inherently multidimensional) metaphors work to model the
"real" world in our language. I believe that a GOOD metaphor has more
properties than just having a "good fit" in the dimensions and range of
a system/phenomena/concept we are modeling. A minimally sufficient
metaphor would have that. And if it *also* yielded a *bad fit* in one
or more dimensions (especially those which we hold high weight on) such
as you describe here with the "toolkit metaphor" immediately calling
forth the need of a "toolwielder". So GOOD metaphor "fits" the
phenomena well (within a relevant and desired subset of it's dimensions
and range) without yielding "false positive" matches in the source
domain ( such as the "tool wielder" example). A GREAT metaphor has
some other properties, such as being inherently parameterizeable....
such as if the "toolkit" had tools which could be more or less
self-motivated/articulated and in invoking the metaphor, one could
appeal to the more rather than less motivated/articulated nature.
Another property is that the metaphor can be deliberately "twisted" or
"broken" to yield interesting variations. I suspect the "toolkit
metaphor" *does* get broken/twisted to fit, but not very gracefully it
would seem. Some metaphors seem more amenable to (deliberate and
thoughtful) distortion than others. Similarly, *mixing* metaphors can
be very useful... blending between two.
Does any one have a better
metaphor?
My training (or lack of imagination) leaves me thinking of gene
expression and regulation in cybernetic terms... feedback loops, etc.
This is not new, so probably not useful to you in this case.
If any of you are wondering
why I am so verbose and wondering, further, when it will stop, try
sending some decent weather to Massachusetts.
Eleventh straight day of
rain.
FWIW, I am enjoying your verbosity... and we've been having our own
spate of wet weather here in NM... very nice for this time of year...
- Steve
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