Sentence:  The process of grinding is, in fact, regarded as indispensable wherever <WSD>truth</WSD> is required, yet that of scraping is calculated to produce a higher degree of <WSD>truth</WSD> than has ever been attained by grinding. 
Meaning of the word marked with <WSD> tags:  Conformity to rule; exactness; close correspondence with an example, mood, model, etc.