灵魂说在西洋哲学中一直是重要关键且永恒讨论的主题。在本文中，笔者将深入探析柏拉图灵魂说并论证灵魂不朽。本文从分析柏拉图对话录中的《斐多》篇出发，运用四个主要论据，论证为何有来生及灵魂不朽：“轮回说--凡物皆从对立面而来”，“灵魂是单一非混成，故不分解，亦不随死亡灭解”，“知识的回忆说”，“理念说”。柏拉图在《理想国》中拓展深化了其灵魂学说，将灵魂喻为“战车”，“理性”驾驭着“欲望”和“感情”。随后，本文讲阐述“柏拉图精神恋爱”的真正含义。柏拉图的灵魂说其政治学说的根基，他的其他学说，如知识论，道德论，辩证法都是以此为基础的。

The theory of soul was an important and crucial theme discussed in the Western Philosophy. In this essay I shall argue and defend Plato’s theory of soul that the soul is immortal. My aim is to focus mostly on the dialogue “Phaedo”, which recounts the last day of Plato’s teacher Socrates, to make a clear outline and analyze why there is an afterlife and why the soul is immortal, using four main arguments to prove that there is life after death, namely, the Cyclical Argument, the Argument from Recollection, the Argument from Affinity, the Argument from the Form of Life. Then I go on to explore Plato’s extended theory of soul in “Republic”, where Plato argues that the soul consists of three basic energies which animate human beings: Reason, Spirit, and Appetite. Then I went on further to study why Plato advocates the Platonic Love. At the end of the paper, I evaluate and conclude that Plato’s theory of soul is the origin of his theory of states, and his other doctrines can not be identified without his theory of soul.