플라톤의 대화편에서 이데아(희랍어 :ἰδέα, 영어:Idea)을 어떻게 이해할까?

  1. The Principle of Commonality. Wherever several things are F, this is because they participate in or imitate a single Idea of F (Phd. 100c; Men. 72c, 75a; Rep. 5. 476a10, 597c).
  2. The Principle of Separation. The Idea of F is distinct from all the things that are F (Phd. 74c; Smp. 211b).
  3. The Principle of Self-Predication. The Idea of F is itself F (Hp. Ma. 292e; Prt. 230c–e; Prm. 132a–b).
  4. The Principle of Purity. The Idea of F is nothing but F (Phd. 74c; Smp. 211e).
  5. The Principle of Uniqueness. Nothing but the Idea of F is really, truly, altogether F (Phd. 74d, Rep. 5. 479a–d).
  6. The Principle of Sublimity. Ideas are everlasting, they have no parts and undergo no change, and they are not perceptible to the senses (Phd. 78d; Smp. 211b).