It seems a sufficient node in and of itself (as I see you've done). Just
throw in a few links. Some nodes can be like that, small essays which
should "inductively" build "up" to converge with the rest of the web.
Others (more my style, see http://pespmc1.vub.ac.be/semioter.html) are more
terse and formal. They should "deductively" build "down".
One or two small points of discussion:
>Downward causation can be defined as a converse of the reductionist
>principle above: the behavior of the parts (down) is determined by the
>behavior of the whole (up), so determination moves downward instead of
>upward. The difference is that determination is not *complete*.
The direction of the causation (up or down) and the amount of determination
(partial or comlpete) are not a priori dependent. Complete bottom-up and
both partial bottom-up and top-down are clear. What would complete top-down
causation be like?
>For example, the coding of amino acids by specific triplets of bases in the
>DNA is not determined by any physical law. A given triplet might as well be
>translated into a multitude of other amino acids than the one chosen in the
>organisms we know. But evolution happens to have selected one specific
>"attractor" regime where the coding relation is unambiguously fixed, and
>transgressions of that coding will be treated as translation errors and
>therefore eliminated by the cell's repair mechanisms.
There is a difference between the entrainment of the genetic code and that
of dynamical systems, although I'm not sure if it's relavent to your point.
Presumably, a chaotic system begins in a fixed, although perhaps not
completely known, initial position, and then as the trajectory develops in
a deterministic way the final basin of attraction becomes clear. But in the
genetic code, the relation between codon and aminoc acid is presumably
arbitrary. Thus we say that this manifests a rule or coding, and thus
semantic relations, whereas the dynamical system manifests only laws of
nature. The uncertainty is epistemic. See the same
http://pespmc1.vub.ac.be/semioter.html.
The problems with this view are that it is actually not possible in
principle to know the initial state of the DS; and conversely that there
likely is SOME level of physical (energetic) "motivation" between a
particular codon and its corresponding amino acid.
O---------------------------------------------------------------------------->
| Cliff Joslyn, NRC Research Associate, Cybernetician at Large
| Mail Code 522.3, NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
| joslyn@kong.gsfc.nasa.gov http://groucho.gsfc.nasa.gov/joslyn 301-286-2598
V All the world is biscuit-shaped. . .