[Retros] What "sound" means.

[Pastmaker at aol.com]

   In a message dated 9/8/02 3:02:33 PM Eastern Daylight Time, DoubleExclam at comcast.net writes: << If the rule changes to 60 moves, a solver could correctly contend that the problem is unsound, because white has a perfectly valid #2 even after the retro-analysis is considered. >> 

   Only lf the solver wishes to use the word "unsound" in an uninformative way, failing to distinguish between something correct when fashioned and something incorrrect when fashioned.
   
   In legal matters, the necessity of knowing the prevailing law at the time an act occurs is required in evaluating the legality of the act. If the act was "legal" at the time it occurred, then that act, when committed, remains "legal", even if the act would be illegal if committed now.
  
   Would one who thinks that a rule change can make a problem retroactively unsound welcome the notion that something he did last year that was then entirely legal could subject him to prosecution because subsequent law has made the act illegal if committed today?  This kind of thing arises regularly in everyday life (e.g., something as simple as smoking a cigarette in a particular area in which smoking has since been prohibited), and we rely on the persistence of the legality of the act in the past. 

   Of course, problemists are free to reject the conclusions of, or analogy to, contemporary jurisprudence, and to use "unsound" to denote compositions both (i) flawed when composed and (ii) correct when composed but subject to a change in rules.
  
   To such a problemist I would ask a small question:  How can one who holds such a view ever call a problem "sound"?  After all, tomorrow's rule change may render it "unsound".  (On the other hand, by the same reasoning, today's flawed composition may become correct by virtue of a fortuitous rule change tomorrow, which means that a problemist holding that view should take care in declaring a problem "unsound" as well.)

   Then again, one can say "sound given the current rules and conventions", or "unsound given current rules and conventions".  But that is exactly what I mean when I use the shorter formula "sound" or "unsound".
   
Tom