Are the underlined words in the sentence an independent clause, a subordinate clause, or neither?

"since early this morning" my friends and i been riding our bikes every evening.
p. s. the quotation is the underlined words.

London includes a quote about john thornton as he is observing hal attempt to motivate the exhausted dogs "it was idle, he knew, to get between a fool and his folly". if the word "idle" is defined as "of no real worth, importance, or significance", what does this statement mean with regard to hal? who is the fool? what is hal's folly? why would john thornton think it of no real worth or useless to intervene?