Source : Webster's Revised Unabridged Dictionary (1913)

Rationalism \Ra"tion*al*ism\, n. [Cf. F. rationalisme.]
   1. (Theol.) The doctrine or system of those who deduce their
      religious opinions from reason or the understanding, as
      distinct from, or opposed to, revelation.

   2. (Philos.) The system that makes rational power the
      ultimate test of truth; -- opposed to sensualism, or
      sensationalism, and empiricism. --Fleming.

Source : WordNet®

rationalism
     n 1: (philosophy) the doctrine that knowledge is acquired by
          reason without resort to experience
     2: the theological doctrine that human reason rather than
        divine revelation establishes religious truth
     3: the doctrine that reason is the right basis for regulating
        conduct [syn: {freethinking}]