principle vs silver bullet

principle

noun
  • A rule used to choose among solutions to a problem. 

  • A fundamental essence, particularly one producing a given quality. 

  • A rule or law of nature, or the basic idea on how the laws of nature are applied. 

  • Bernoulli's Principle 

  • An original faculty or endowment. 

  • A fundamental assumption or guiding belief. 

  • A source, or origin; that from which anything proceeds; fundamental substance or energy; primordial substance; ultimate element, or cause. 

  • Moral rule or aspect. 

verb
  • To equip with principles; to establish, or fix, in certain principles; to impress with any tenet or rule of conduct. 

silver bullet

noun
  • Any straightforward solution perceived to have great effectiveness or bring miraculous results. 

  • A thermometer, especially one used for rectal temperature readings. 

  • A cocktail somewhat like a martini. 

  • A bullet made of silver, usually with reference to the folkloric belief that such bullets are the only weapons which can kill a werewolf, vampire, or other monster. 

How often have the words principle and silver bullet occurred in a corpus of books? (source: Google Ngram Viewer )