Ratiocinator
The Century Dictionary and Cyclopedia
noun.
One who ratiocinates; a reasoner.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
someone who reasons logically
Word Usage
"The father of mysteries dies of unknown causes after a three-day disappearance; the ratiocinator and critic willingly embraces Lethe and Nepenthe."
Hypernym
Words that are more generic or abstract
thinker
Hyponym
Words that are more specific
analogist
casuist
sophist