Yes, Bruce. And the collection of variables have some allowable (and hopefully specified) value range, or “scope”. In addition, the observer is normally operating within the scope and perspective of some institutional context (both immediate organization and legal/governmental and social framework, as well as the “ecosystem” created by the existence of other institutions). The business model and institutional objectives (i.e., charter, mission statement, operating domain, etc.) usually drive many, if not most or all of the variable ranges for the set of variables that define the purpose and boundaries of the system. Too bad that this institutional perspective and frame of reference is left as “an exercise for the student” in much of system engineering and is usually left mostly implicit rather than explicitly delimited and specified.
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Bruce Schuman
Sent: Friday, April 18, 2014 5:00 PM
To: '[ontolog-forum] '
Subject: [ontolog-forum] FW: Formal or functional specifications
To add a couple thoughts to our general discussion of "how good philosophy leads to good engineering", I thought I would send along a couple of graphic snips from the British engineer W. Ross Ashby's "Design for a Brain".
These ideas have been bedrock for me. Ashby clearly describes this same issue that has come up several times -- that the variables describing any "system" are selected by the observer. He punches straight through to the core when he talks about "readings on dials".
"A system is a collection of variables". That is what an algebraic analyst wants to hear. Now, let's explain why it is true for database modeling...
See http://originresearch.com/docs/DesignForABrain.pdf for the complete text.
NETWORK NATION: http://networknation.net
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From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of John F Sowa
Sent: Friday, April 18, 2014 9:34 AM
To: '[ontolog-forum] '
Subject: [ontolog-forum] Formal or functional specifications
I sent the following reply to a discussion on the ontology summit list, but the issues are critical for any ontology.
-------- Original Message --------
Subject: Shareable versus reusable, or shared and reusable
Overly precise specifications can block interoperability and reuse in engineering, medicine, and other fields. Engineers complain that computerized tools can make functional replacements more difficult.
They can also be a deterrent to innovation.
For many purposes, a simple list can be hard to improve:
Toast, muffin, croissant, or daily special
As another example, the shift away from incandescent light bulbs has drawn attention to functional requirements that nobody imagined.
Reducing heat is good. But LED traffic lights don't generate enough heat in winter to melt snow and ice. An incandescent bulb gets hot, but it tolerates heat in an enclosed space. The number of unexpected consequences -- both good and bad -- is open-ended.
Sometimes, the exact spec is critical, and a repair that seems to be a functional replacement can create a disaster. But patients have died because a physician did not know that another option was possible.
For humorous examples, google "redneck repairs". But the questions are serious: Is form or function more important? How much precision is appropriate? What tradeoffs are possible, desirable, or dangerous?