The Collaborative International Dictionary of English v.0.48:

Scientifically \Sci`en*tif"ic*al*ly\, adv.
   In a scientific manner; according to the rules or principles
   of science.
   [1913 Webster]

         It is easier to believe than to be scientifically
         instructed.                              --Locke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scientifically
    adv 1: with respect to science; in a scientific way; "this is
           scientifically interesting"