思想與靈魂，是亞里斯多德思想中二個重要的議題，後者引起十三世紀靈魂之爭，爭論的重點是人的理智。亞里斯多德是從理智在思想時的功能而論理智，但他的詮釋者轉而探討理智的本性。如此經過幾個世紀的詮釋，這個能製造一切的主動理智(nouspoiietikos)，與能成為一切的被動理智(nous dunamei)，在他的詮釋者的手中，成為物質性的理智(passible intellect)，與有神性的主動理智(anent intellect)。亞里斯多德最有名的詮釋者亞味羅(Averroës)認為，被動理智全人類共有一個，十三世紀時，他的推崇者西杰(Siger of Brabant)極力擁護這種說法，這與基督宗教的信仰相抵觸，因而引起一番激烈的爭論。本文主要是說明十三世紀靈魂之爭，是對理智詮釋角度的轉變而引起，同時也介紹多瑪斯面對此爭論所做的一些說明。

Two of the major themes in Aristotle’s philosophy are thought (nous) and the soul. The latter becomes in the thirteenth century a much debated problem. The heart of the controversy concerns the agent intellect. When analyzing the rational soul and its function in the process of thinking, Aristotle described the two functions of the intellect as: the intellect that makes all things and the intellect that becomes all things. However, subsequent commentators are more interested in the nature of the intellect than its function. This shift in the point of view leads to the heated debate in the thirteenth century. For according to the Commentator (Averroes), the agent intellect is divine and the possible intellect (passible intellect for Averroes) is one for all mankind. Signer of Brabant, a faithful follower of Averroes, adheres strongly to this position. It was at this critical moment when Thomas Aquinas was summoned to present his view on the problem. This paper tries to trace the development of the debate back to Aristotle and shows that the reason for the debate is the turn in the point of vies concerning the agent intellect.