'Unjustified variation' in contrast to 'rational variation.' ""The emphasis on unjustified makes a subtle point. An unjustified variation is one for which the truth has not yet been established, but one for which truth is not precluded. Justification comes after a belief has been generated and tested. While it might appear that intelligent, preadapted, informed variation is to be preferred, such variations are restricted to knowledge already achieved."" (Weick, 1979, p 123).