What is “paradigm”?

@techreport{GokturkParadigm,
   address = {Oslo, Norway},
   author = {Göktürk, Erek},
   institution = {Department of Informatics, University of Oslo},
   title = {What is ``paradigm''?},
   type = {Essay},
   urlpdf = {http://folk.uio.no/erek/essays/paradigm.pdf},
   year = 2007
}