Sentence:  The central concern of Erich Auerbach 's impressive volume called Mimesis is to describe the shift from a classic theory of imitation ( based upon a recognition of <WSD>levels</WSD> of truth ) to a Christian theory of imitation in which the levels are dissolved . 
Meaning of the word marked with <WSD> tags:  a specific identifiable position in a continuum or series or especially in a process