Remove sketch of "Subtlety" section

Author: brandon-rhodes

contingent/chapter.rst

@@ -1246,70 +1246,6 @@ of ``title_of('tutorial.txt')`` is exactly equal to the old one
 stopped the build process from having to recompute
 any of the consequences downstream of it.
 
-Subtlety
-========
-
-<!-- HMM. WAIT. By this point we are kind of set.
-The story is nice and seems done.
-Do we really need a secion on how the graph can
-change even as you traverse it?
-I am not sure. Maybe it should be axed.
-What do you think, Dan?
-Am leaving it hear til you give an opinion. -->
-
-
-In fact:
-
------------------ ignore everything -----------------
---------------- from here down -------------
---------------- unless dan chooses to resurrect it ------------
------------ otherwise, we axe it in favor of a triumpant conclusion! --------
-
-
-
-
-Why would the graph change as we are calculating it?
-
-The edges we have considered so far between documents are the result of
-static site design — here, the fact that each HTML page has a link to
-the preceding blog post.  But sometimes edges arise from the content
-itself!  Blog posts, for example, might refer to each other
-dynamically::
-
-    I have been learning even more about the Pandas library.
-    You can read about my first steps in using it by visiting
-    my original `learning-pandas`_ blog post from last year.
-
-When this paragraph is rendered the output should look like:
-
-..    x...original `Learning About Pandas`_ blog post from last year.
-
-Therefore this HTML will need to be regenerated every time the title in
-``learning-pandas.rst`` is edited and changed.
-
-After running a rebuild step for a consequence, therefore, we will need
-to rebuild the edges leading to it so that they reflect exactly the
-inputs it in fact used during its rebuild.  In the rare case that the
-new set of edges includes one from a yet-to-be-rebuilt consequence
-further along in the current topological sort, this will correctly
-assure that the consequence then reappears in the ``todo()`` set.  A
-full replacement of all incoming edges is offered through a dedicated
-graph method.  If an update were added to the text of post A to mention
-the later post C, then an edge would need to be generated to capture
-that:
-
-x>>> g.add_edge('C.title', 'A.html')
-
-Thanks to this new edge, post A will now be considered one of
-consequences of a change to the title of post C.
-
-x>>> g.recursive_consequences_of(['C.title'])
-['A.html']
-
-How can this mechanism be connected to actual code that takes the
-current value of each node and builds the resulting consequences?
-Python gives us many possible approaches.  [Show various ways of
-registering routines?]
 
 
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