The Collaborative International Dictionary of English v.0.48:

Dianoetic \Di`a*no*et"ic\, a. [Gr. ?; dia` through + ? to
   revolve in the mind.] (Metaph.)
   Pertaining to the discursive faculty, its acts or products.
   [1913 Webster]

         I would employ . . . dianoetic to denote the operation
         of the discursive, elaborative, or comparative faculty.
                                                  --Sir W.
                                                  Hamilton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dianoetic
    adj 1: proceeding to a conclusion by reason or argument rather
           than intuition [syn: dianoetic, discursive]