Sentence:  Indeed, as we have further suggested, this follows on also, in the eyes of the pilgrim- visitors themselves, from their own earlier moment of <WSD>discrimen</WSD>, at the point when the "old man'"s pilgrim-interlocutor had similarly exclaimed "O Hercules" on learning the Sphinx-like nature of the explanation being proffered to them. 
Meaning of the word marked with <WSD> tags:  A crisis or turning point; A situation that changes how the future will unfold.