Sentence:  CONSIDER what it is the inchworm measures with his ridiculous lurch-and-drag walk; he measures his way down the aeons of <WSD>unproof</WSD>; he measures nothing that is not a thought of God; he measures his life that it may be shared with all; [...] 
Meaning of the word marked with <WSD> tags:  Absence or lack of proof or evidence; prooflessness.