Initially attracted to Aristotelianism, Avicenna touched on almost all aspects of Aristotle's philosophy. One of them is the problem of the soul (nafs), of which his accounts reflect both Aristotle's and Plotinus's views. Avicenna's psychological accounts begin with the Aristotelian definition of the soul. With Aristotle he seems to accept the entelecheia view of the soul, which holds that the soul is an actualisation of the body having life in it, that the soul has no activity independently of the body. But he also accepts the immortality of the soul, which seems to be a non-Aristotelian trait. These two views seem to be divergent and contrary. Since Avicenna seems to accept these two apparently contrary views, it is a concern whether he maintains consistency in his system.In order to explore this, we shall take up a reconciliation methodology, focusing on the hypothesis that he combines aspects or elements from the two divergent philosophical systems so as to produce an overall position which can be regarded as consistent. Like Aristotle, A vicenna, while talking about the vegetative and animal souls, holds a functionalist view of the soul, that the soul acts in association with the body; thus properly using the Aristotelian entelecheia formula. But he also holds the immortality of the rational soul, which he sees as a substance capable of subsisting by itself and functioning independently of the body, which suggests he cannot properly apply here the entelecheia doctrine. The thesis investigates how A vicenna understands and applies Aristotle's entelecheia doctrine, and distinguishes his accounts of the non-rational souls (plant and animal) from those of the rational soul (human). A vicenna is seen to have understood the Aristotelian entelecheia doctrine in two different senses in order to hold two different views of the soul-as form and as substance. This thesis examines how he begins with the Aristotelian definition and framework of the soul and slips away from the fundamental themes of Aristotelianism, and accepts certain elements of neo-Platonism by tracing as many divergences and analogies as possible between Avicenna's concepts and those of Aristotle and Plotinus.The thesis also explores whether Avicenna, by modifying the Aristotelian sense of the entelecheia doctrine, can derive substantial arguments for the immortality of the soul from the Aristotelian tradition. We endeavour to show that although there is a tendency to attribute the view of the immortality of the soul to Aristotle, it is inconsistentent, given the orthodox Aristotelian platform of the entelecheia doctrine, to hold the two views, which are in fact divergent. Avicenna, although he modifies the entelecheia doctrine in order to accommodate the immortality view of the rational soul and attributes it to some extent to Aristotle's philosophy, does not, indeed, find convincing argumentation in the Peripatetic tradition; rather, his arguments, we shall show, are derived from neo-Platonism, mainly from Plotinus. This involves him in reconciling both views, selecting the elements that best suit his overall position, and evidently in doing so he sets himself astray from the mainstreams of both Aristotelianism and neo-Platonism
