Historical clue formulations

• "It's ___, not a science" — 2019-04-09
• Not a science, but ___ — 2019-04-07
• "Conversation is ___ in which a man has all mankind for his competitors": Ralph Waldo Emerson — 2009-02-26
• "Dying / Is ___, like anything else": Sylvia Plath — 2007-02-26
• Not a science, but___ — 1996-01-18
• "Cookery is become _____": Burton — 1994-12-22