Who does not mix with the crowd knows nothing.

　　eg：His opinion shows us that he is the man who does not mix with the crowd knows nothing.

　　中英俚语俗语来源：札记·学记："独学而无友，则孤陋而寡闻。"

　　同义词：一无所知 To be in the dark.

　　反义词：耳听八方 Have an ear to the ground.