《庄子·外篇·秋水》
可以用言语来谈论的东西，是事物粗浅的外在表象;可以用心意来传告的东西，则是事物精细的内在实质。言语所不能谈论的，心意所不能传告的，也就不限于精细和粗浅的范围了。
可以言论者，物之粗也；可以意致者，物之精也；言之所不能论，意之所不能察致者，不期精粗焉。
Things that can be discussed are superficial and represent external aspects while things that can be conveyed are subtle and represent the internal substance. Things that cannot be discussed or conveyed are not limited to categories of subtle or crude.