RE: Re: [xml-dev] The Rule of Least Power - does it miss the point?

["Bullard, Claude L \(Len\)" <len.bullard@intergraph.com>]

It's a weak rule.  At the network level where one prefers the 
simplest interface and the fewest verbs, (Take a deep breath 
and say HTTP Over All Alternatives (HOAA!)), it is the case 
because the evolution is measured over long time spans, 
large distances, lots of different social systems, and so 
on.  In other words, transport rules.  But a programming 
language power rule per se (and I don't count HTML as a programming 
language) is specific to application.   Think local.  The 
rules here are context-dependent and the rule starts to 
break up (global constraints aren't as important).

One can (and have) discuss this as a subjective system 
approach (subjective vs objective systems in cybernetics), 
but that won't change the minds of those who believe they
have authored a sound rule based on sound principles.  The 
shift in the wording from "Principle of Least Power" to 
"Rule of Least Power" may signify an implicature for 
the intent of the authors, but I don't find many inferences 
for the hearer of great value past ones we all generally 
accept and apply with respect to scale and locale.

In other words:  this one can be ignored if one isn't 
too concerned about the clubs they are seeking membership 
in because open inspection for reuse isn't the only goal 
of systems builders.  Otherwise you'd see a lot more 

<ssn>Steal My Identity Until The Creditors Find Me</ssn>

in XML.  The power of a language is one part operational 
(eg, Turing complete) and one part expressive (can I 
encrypt this) and so on.  One would say, given a certain 
context (norms), get these operations (affordances) and 
no more.  As Fielding pointed out, Rule of Least Power 
aligns with Principle of Least Authority, and if indeed 
the web is a Social System as Fielding claims, be aware 
that that is an abstact class.  In the real world, instances 
of these classes oscillate against and for one another, 
so in the end you will be using Filters to tune them.

See PIDs in Process Control Theory.

len


From: Michael Champion [mailto:michael.champion@hotmail.com]

I'm sure this comes across as a bit snarky, but the only way I can understand this "Rule" is by applying my training in Political Science, not Computer Science.  This is a classic example of a single decision with multiple rationales, none of which by itself is compelling but the sum total is easier for the group to accept than oppose.  (A bit like Fearless Leader's decisions vis a vis Iraq ---no single rationale for invasion  holds water, but collectively it was minimally satisfactory to people who really did believe there were WMDs, those who really believed there was an al Qaeda link, those who really believed the neocon theory about stabilizing the region thru democracy, those who wanted to finish the job that George Sr. started, and all sorts of unsavory reasons I'm sure)

In the TAG's case, the Rule of Least Power minimally satisfies:
- Those who just think that "Occam's Razor applies to computers", as Henry T. put it, and recommend erring on the side of simplicity as a general rule
- Those who seem to dislike the AJAX stuff and want an authoritative reason not to take it farther than it already has
- Those who sincerely believe that one can declaratively analyze a web app  to prove that it does what it is supposed to do
- Those who want to rationalize the Worse is Better dynamic that has given us the Web as we know it
- etc.

Given the case of characters, there's probably a "somehow advance the Semantic Web" rationale that I can't think of :-) 

Usual disclaimer about who I'm NOT speaking for, blah blah.