What does "明微推远，憭若蓍蔡" mean?
My interpretation:


  明微推遠，憭若蓍蔡
  
  [his words are] clear (明), precise (微), incredibly profound (推遠), as wise (憭) as that of (若) the most renowned and famous (蓍蔡)


As for the reference definition for「蓍蔡」:


  漢語大詞典
  
  
  比喻德高望重的人。 
  
  
  明　張居正　《少師存齋徐相公七十壽序》：＂天下方以公為蓍蔡，何可一日無也。＂
  明　陸深　《溪山餘話》：＂公和易，不事邊幅，喜為後生輩談論講說，終日不倦……所謂國家之蓍蔡，若人是已。＂ 
  清　褚人穫　《堅瓠秘集・守龜》：＂古人目老成人，則曰國之蓍蔡。＂