The Collaborative International Dictionary of English v.0.48:

Objectiveness \Ob*jec"tive*ness\, n.
   Objectivity.
   [1913 Webster]

         Is there such a motion or objectiveness of external
         bodies, which produceth light?           --Sir M. Hale
   [1913 Webster]

WordNet (r) 3.0 (2006):

objectiveness
    n 1: judgment based on observable phenomena and uninfluenced by
         emotions or personal prejudices [syn: objectivity,
         objectiveness]