Re: Co-optation Today

On Wed, 09 Jan 2008 16:20:28 GMT, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:

r norman wrote:
On Tue, 08 Jan 2008 19:51:20 -0800, John Harshman
<jharshman.diespamdie@xxxxxxxxxxx> wrote:
Here: a nested hierarchy is a set of groups in which each group has one
of two relationships with each other group; either the two groups are
wholly disjunct, or one group is entirely included within the other.
Partially overlapping groups are right out. Phylogenies can further be
described as natural nested hierarchies: only one hierarchical
arrangement of groups will work.

Actually a nested hierarchy is simply a directed rooted tree
structure, that is, an connected graph without cycles where each node
has no more than one parent (edge directed toward the node) and has
zero or more children (edge leaving the node). Such trees are
commonplace in programming.

No, a nested hierarchy can be *represented* as a tree structure. It can
be represented in other ways too, for example by Venn diagrams.
Programming structures are not natural nested hierarchies, i.e. they are
imposed by fiat rather than arising out of the characteristics of the
elements. One could rearrange those elements freely into a different
hierarchy. As such, it's similar to any arbitrary division. The geologic
time scale is a nested hierarchy too, with eons, eras, periods, epochs,
and ages. But it's not a natural one. We do make nested hierarchies all
the time, but they just don't have the features of a natural hierarchy,
the sort that results from common descent.

We can disagree about the nature of reality vs. representation for a
completely abstract structure or concept. I would argue that every
nested hierarchy can be so represented and that every such tree
represents a nested hierarchy. They are in a one-one correspondence
and therefore, in a sense, can be considered equivalent. I was simply
responding to you statement: "A nested hierarchy is...." without
regard to whether it is natural or artificial or whether it is
arbitrary or fixed by the inherent properties of the nodes.

.

Relevant Pages

  • Re: Co-optation Today
    ... a nested hierarchy can be *represented* as a tree structure. ... Programming structures are not natural nested hierarchies, i.e. they are imposed by fiat rather than arising out of the characteristics of the elements. ... That's why I say that a tree is a representation of the hierarchy, ...
    (talk.origins)
  • Re: Yet again, human evolution: huh?
    ... >>>I'm still not entirely grasping the concept of the nested hierarchy. ... >>provide clues to the structure of that tree. ... > example, all humans are primates, but not all primates are humans; ... would it be so far fetched for an octopus to evolve a skull? ...
    (talk.origins)
  • Re: Yet again, human evolution: huh?
    ... >> I'm still not entirely grasping the concept of the nested hierarchy. ... none of the circles cross each ... > provide clues to the structure of that tree. ... example, all humans are primates, but not all primates are humans; ...
    (talk.origins)
  • Re: Co-optation Today
    ... a tree is nothing but nodes and arcs. ... I don't think a nested hierarchy can exist even in the abstract with no values. ... Sounds reasonable, if by "value" you mean only some kind of label, and if by "leaf" you refer to a branch with one end free (i.e. a node with only one branch connected to it, a terminal node). ... When a message starts a new thread, its reference string is null. ...
    (talk.origins)
  • Re: More proof you boons dont know what your on about.
    ... Or the amount of genes a life form has. ... Screamed spintwitty at the face in the mirror. ... A nested hierarchy is 'groups within groups'; your inexplained 'tree' ...
    (talk.origins)