Source : Webster's Revised Unabridged Dictionary (1913)

Polemics \Po*lem"ics\, n. [Cf. F. pol['e]mique.]
   The art or practice of disputation or controversy, especially
   on religious subjects; that branch of theological science
   which pertains to the history or conduct of ecclesiastical
   controversy.

Source : WordNet®

polemics
     n : the branch of Christian theology devoted to the refutation
         of errors