A question is often asked, "What is the application of this move?"  That's a good question, but if that's the only question we ask about forms, we're missing something extremely important.

A more thoughtful question is, "What are the patterns for?"  Sometimes the answer is given, "They're traditional".  That's true, but not that helpful, General Choi gave us the 24 patterns, but "tradition" does not answer the question of "why".  Taekwon-Do is an extremely practical martial art, drawing on prior martial arts but refined by science and usefulness.  It is concerned with defending oneself or others, so the idea of pattern movements being arbitrary (and ultimately unimportant) seems entirely at odds with the history and purpose of Taekwon-Do.

You can see where my questions lead.  However, books on patterns do not answer these questions.  Authors describe legitimate applications for individual moves but when you put all those applications together, there is no consistency or logic to what the opponent is doing.  In some cases authors offer a wild explosion of explanations for individual move applications (often some very dubious applications and often changing the move greatly to make that application work) .  Clearly they do not address the "why" of the pattern; in fact they never seem to look for it.

I want to know why the pattern moves are in the order they are.  Am I wrong?  Let's consider the following description of patterns:

Patterns are various fundamental movements, most of which represent either attack or defense techniques, set to a fixed and logical sequence.

The student systematically deals with several imaginary opponents under various assumptions, using every available attacking and blocking tool from different directions. Thus pattern practice enables the student to go through many fundamental movements in series, to develop sparring techniques, improve flexibility of movements, master body shifting, build muscles and breath control, develop fluid and smooth motions, and gain rhythmical movements.

It also enables a student to acquire certain special techniques which cannot be obtained from either fundamental exercises or sparring.  In short, a pattern can be compared with a unit tactic or a word, if fundamental movement is an individual soldier's training or alphabet. Accordingly, pattern, the ledger of every movement, is a series, of sparring, power tests, feats and characteristic beauty
--General Choi Hong Hi, Encyclopedia of Taekwondo, Volume 8, p. 13
So from the founder of Taekwon-Do we are told the following about patterns:
  • Movements are mostly attack or defense techniques.
  • Movements are in a logical sequence.
  • Forms are dealing with multiple imaginary opponents.
  • There are assumptions to what the opponents are doing.
  • Forms perfect techniques that cannot be done as exercises or even sparring.
I believe I am standing on the firmest ground in pursuing form purpose, given General Choi's explanation of purpose.
That brings us to another point--why don't General Choi's Encyclopedias provide the form explanations?  They provide many examples of what individual moves are for and eliminate the need for the sometimes ludicrous applications suggested by some recent authors but it seems inarguable that these are just possible explanations for the moves, not necessarily the purpose in the form itself.  Let me illustrate: 
In Encyclopedia Vol. 10, page 86-88, Toi-Gye
  • Move 26 is a Snap Kick to an kneeling opponent's philtrum.
  • Move 27 is a High Thrust to a standing opponent's eyes.
Individually, each application is understandable.  However If one assumed that these are the applications within the pattern you would have the ludicrous picture of a kneeling opponent that you strike so hard he somehow bounces up to a standing position (though without flying backward at all).  Surely no one thinks General Choi wanted us to come away with that thought.
Lest someone argue that the above is a misprint many more similar examples exist as well as an instance in which the Encyclopedia shows in the form different applications for one move.  Clearly General Choi is showing us move possibilities which may or may not be the actual application of that move when it is done within the form.
Another question comes to mind.  Why didn't General Choi explain exactly what the move applications are within a form?  That may best be answered by pointing to the author C.S. Lewis.  His chronicles of Narnia series seemed to lack an explanatory theme.  People asked him directly; he seemed to give hints but didn't answer.  For decades people puzzled over the problem, sometimes denying that there was any theme.  Nonetheless, just a few years ago this puzzle was solved very convincingly, despite people working on it since the 1950s.  In retrospect the explanation is very obvious.
I think we face the same kind of challenge but with every reason to think we can succeed.  The General considered the 24 patterns his gift to the future.  Don't we have a responsibility to do what he instructed, and "know the purpose for each movement"?
For starters--how will the reverse punches in Hwa-Rang work? 
Jim Simons