Sentence:  The fact that he has cast over those materials the light of a skeptical <WSD>mind</WSD> does not make him any the less Southern , I rather think , for the South has been no more solid than other regions except in the political and related areas where patronage and force and intimidation and fear may produce a surface uniformity . 
Meaning of the word marked with <WSD> tags:  that which is responsible for one's thoughts and feelings; the seat of the faculty of reason