\In`stru*men"tal*ism\, n. (Philos.)
The view that the sanction of truth is its utility, or that
truth is genuine only in so far as it is a valuable
instrument. -- {In`stru*men"tal*ist}, n.

      Instrumentalism views truth as simply the value
      belonging to certain ideas in so far as these ideas are
      biological functions of our organisms, and
      psychological functions whereby we direct our choices
      and attain our successes.                --Josiah
                                               Royce.