I need to learn what?

"無名指" is the 4th finger, i.e., ring finger.

孟子曰：「今有無名之指，屈而不信，非疾痛害事也，如有能信之者，則不遠秦楚之路，為指之不若人也。」 (wikisource)

孟子 said that, now somebody suffers from ring finger contracture with extension limitation, but he doesn't feels any painful or uncomfortable. If there is a doctor can cure this problem, although the doctor lives as far as 秦、楚， this patient will make miracles to visit him, for the finger than other people's.