What do we understand from the verse: "Have they not traveled through the land, so that their hearts (minds) may be able to reason thereby?" (Qur'an 22:46)? And does this mean that thinking is located in the heart and not the brain, and that the heart, the seat of emotions, is also the seat of abstract rational thought, and if so, what is the function of the brain?

The heart and its relationship to the brain, and the seat of the intellect within them, are ancient matters of dispute. Sheikh al-Islam Ibn Taymiyyah differentiated between the origin of thought and contemplation, which is in the brain, and the origin of will and choice, which is in the heart. The noble verse: "Have they not traveled through the land, so that they might have hearts by which to reason and ears by which to hear? For indeed, it is not eyes that are blinded, but rather the hearts in the breasts that are blinded" indicates that the heart is not merely an organ, but rather has a direct relationship with the intellect. Modern scientific research has indeed proven the "rationality and consciousness of the heart."