Where is the location of one's reasoning? Is it in the heart or in the brain?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The difference in opinion regarding the location of reasoning in one's body started a long time ago. According to the Shaafi‘i and Scholastic Theology scholars, the heart is the place of one's reason. The same view was also adopted by philosophers.

On the other hand, Abu Haneefah was of the view that the brain is the place of one's reason, which is also the view of physicians.

Those who advocated the first view quoted the following verses as proof: Allaah The Almighty Says (what means):

Commenting on the second verse, scholars of Tafseer (Quranic exegesis) mentioned that the heart here refers to one's reasoning.  They quoted the Hadeeth of the Prophet, sallallaahu ‘alayhi wa sallam, in which he said that the righteousness or corruption of the whole body is contingent on the righteousness or corruption of the small lump of flesh, which is the heart. [Muslim]

In this Hadeeth, the Prophet, sallallaahu ‘alayhi wa sallam, said that the righteousness or corruption of the whole body depends on the state of the heart, and of course the brain is a part of the body and, therefore, its righteousness or corruption depends on the state of the heart. For this reason, they concluded that it is not possible to say that the brain is the place of one's reason.

Those who advocate the view that reason is located in one's brain argued that brain damage causes the damage of one's reason; and that epilepsy is one of the results of brain damage.

When Shaykh Al-Islam Ibn Taymiyyah was asked about reasoning and its location in one's body, his answer was that reason drives the human self as a whole and organizes its affairs. Concerning its location inside the body, he said that it is in one's heart.  As proof, he quoted the verse in which Allaah The Almighty Says (what means): {So have they not traveled through the earth and have hearts by which to reason?} [Quran 22: 46] He also used as proof the Hadeeth of  Ibn ‘Abbaas who was asked about his extensive knowledge and his answer was that he gained it through his frequently-questioning tongue and frequently-reasoning heart.

However, Ibn Taymiyyah mentioned that the term ‘heart’ may refer to either of two things: First, the pine-shaped lump of flesh that lies on the left side of the human body and has a black clot inside it, as stated in the aforementioned Hadeeth of the Prophet, sallallaahu ‘alayhi wa sallam, about the dependence of the righteousness or corruption of the whole body on the heart. Second, it may refer to the essence of the human being in general, such as saying the heart of the grain of wheat, almond and walnut.

Consequently, he said that if the word ‘heart’ refers to the essence of the human being in general, then reason in this case is connected to both the heart and the brain, because they are parts of the body; and that is why many physicians are of the view that the brain is the place of one's reason. The same view was also held by Imaam Ahmad . According to a group of the companions of Imaam Ahmad , the original place of one's reason is his heart then if it becomes perfect, it settles in the brain.

Ibn Taymiyyah added that considering that the soul is connected to both the heart and the brain, likewise reason is connected to both of them. An action does not occur unless it is conceived in one's brain and intended in one’s heart and, therefore, both of them participate in it. From this we conclude that reason is connected to both the heart and the brain.

The words of Shaykh Al-Islam Ibn Taymiyyah in this regard, are the closest to sound reason, however, we should always bear in mind that discussing such matters is discussing matters related to the soul, and Allaah The Almighty Says (what means): {And they ask you, [O Muhammad], about the soul. Say, "The soul is of the affair of my Lord. And mankind have not been given of knowledge except a little."} [Quran 17: 85]

Allaah Knows best.