The Collaborative International Dictionary of English v.0.48:

philosophize \phi*los"o*phize\ (f[i^]*l[o^]s"[-o]*f[imac]z), v.
   i. [imp. & p. p. Philosophized
   (f[i^]*l[o^]s"[-o]*f[imac]zd); p. pr. & vb. n.
   hilosophizing (f[i^]*l[o^]s"[-o]*f[imac]`z[i^]ng).]
   To reason like a philosopher; to search into the reason and
   nature of things; to investigate phenomena, and assign
   rational causes for their existence.
   [1913 Webster]

         Man philosophizes as he lives. He may philosophize well
         or ill, but philosophize he must.        --Sir W.
                                                  Hamilton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

philosophize
    v 1: reason philosophically [syn: philosophize,
         philosophise]