Sentence:  The historian ... is a sort of novelist, but one who instead of inventing plot and character is obliged to discover them; who instead of setting characters in motion against one another with foreknowledge of their natures and destinies tries to guess at what often <WSD>incoherent</WSD> characters were up to amid a distraction of lies and suppressions. 
Meaning of the word marked with <WSD> tags:  Not making logical sense; not logically connected or consistent.