premise: I said nothing and gave no advice , not having lived seventy-five years for nothing .<br>I knew that Doctor John 's decision was manly and right and fair ; but I also knew it was all nullified by the fact that Marcella already loved him .<br>So much I knew ; the rest I was left to suppose .<br>The Doctor and Marcella told me much , but there were some things too sacred to be told , even to me .<br>So that to this day I do n't know how the doctor found out that Marcella loved him .
hypothesis: The person who gave no advice did not have to guess whether Marcella loved the doctor.
reason: The text says [he] "knew it was all nullified by the fact that Marcella already loved him. So much I knew ; the rest I was left to suppose" -- the ambiguous phrase 'the rest' confused the model.