至今，在柏拉圖學者間，對於如何詮釋柏拉圖《理想國》476d-480e仍無定論。因為希臘文動詞ειναι的語意含糊，具有多重意義，造成對這段文字詮釋上的困難。本文目的是在討論ειναι的各種不同的意義，進而找出最適於這段文字的解釋。第一部份是有關存在性意義的討論，第二部份是有關真實性意義的討論，第三部份是有關描述性意義的討論。在討論的過程中，我將指出為什麼第一與第二義的用法在這段原文中並不恰當，只有第三種意義可以給予這段原文完整而合理的詮釋。

　　　　　There is so far no agreement among Plato's commentators ass to how to interpret the Greek verb ειναι at the passage 476d-480e of the Republic. For the ambiguity and multi-meaning of the verv cause difficulty in interpreting the passage in question. The purpose of this paper is to discuss the different meanings of the verb ειναι to see which one of them is the suitable candidate for interpreting the present passage. The first part of this paper is on the existential sense of the verb; the second part is on the veridical sense; and the final part of the paper is on the predicative sense. In the course of discussion, I shall show the reasons why the first and second sense of the verb ειναι cannot fit on with the passage, only can the third one give a complete and reasonable account of it.