亞理斯多德的《論靈魂》一書探討所有有機體；植物、動物和人之所以有生命的事實，以及它們分別可以有的活動。他將靈魂定義為生命的原理，靈魂是潛能中可以有生命的自然身體之所以活著的現實原理。 有關靈魂不朽的問題是亞理斯多德思想中最不清楚的問題。唯可以明確的即靈魂不朽的概念是他早期已遺失的著作中的核心問題。在早期著作中，他基本上受柏拉圖的影響，肯定靈魂不朽。在他的成熟期著作中，亞理斯多德以物理學中的形質論，類比的用到靈魂與身體之間的是形式與質料之間關係。人是一完整的人，靈魂不能分開、自立地存在，靈魂當與身體組合成一完整的人。在形質論的框架下如何解釋在身體死亡後，靈魂仍有繼續存在的可能，就成為哲學家不斷地探討的問題。 在本文的探討中，我們指出亞理斯多德雖從沒有一系列有關靈魂不朽的論證，但從他肯定理性才是人的靈魂，它是形上的簡單，是非物質的，它的固有活動是非物質的活動，他肯定靈魂的本性是不朽的。理性非身體的形式，它是在自身分開的實體，形質論不能用到理性與身體的關係。不同於植物和動物的靈魂當與身體組合在一起，理性是不同類的靈魂。從理性是分開的實體，它的活動與身體無關，它是非物質的，它因而是永恆和不朽的。亞理斯多德的這種有關理性的靈魂的獨特本性和活動的特性有著濃厚的柏拉圖色彩。本文旨在論證靈魂不朽的概念是亞理斯多德早期思想中的主要概念，也是他一生所未曾放棄的。

Abstract Aristotle’s De anima is the first book which deals with all sorts of organism: the living facts of all the plants, animals and human beings, and their proper activities or functions respectively. Soul is defined as the vital principle which enables the natural body from having life in potency to be a living body in act. The problem regarding the immortality of the soul is altogether unclear in Aristotle’s writings. However, what is definite is that the concept of immortality of the soul is one of the central ideas in his early lost writings. At his early age, Aristotle was influenced by Plato and accepted the idea of the immortality of the soul. In his mature writings, Aristotle develops his own philosophy. When he speaks about psychology, he speaks in terms of the hylomorphism in the Physics. According to which, all the material substances are composed of form and matter, so is a man composed of soul and body. For Aristotle, as a man is a whole man, the soul cannot subsist separately in itself. In such a case, the possibility of the survival of the soul, after the death of body, becomes the repeated question on which philosophers have been trying to investigate. Aristotle never makes any demonstration of the immortality of the soul, as Plato does before him. Nevertheless, he affirms that the intellect is the verysoul of human beings, being metaphysically simple and immaterial, and its activity is immaterial in nature. Intellect is not the form of body; it is a separable substance in its own right. In fact, hylomorphism cannot be referred to the relationship between intellect and body. Intellect is different from the vegetative and animal souls which are bound to be united with bodily organs, whereas intellect can be a separable substance in its own right. It is a different genos of soul. Since intellect is immaterial, its activities are independent from body. It is therefore eternal and immortal. The Aristotelian idea of the intellect is platonic in essence. Aristotle has never given up his early idea of the immortality of the soul throughout his whole life.