Surah 22:46
"Have they not traveled on the earth? Do they have hearts to understand with or ears to hear with? Surely it is not the sight (which) is blind, but the hearts which are within the chests are blind."
The Heart as the Organ of Thinking
The Qur'an literally identifies the physical heart inside the chest as the biological organ that thinks, reasons, and understands ('have they not hearts wherewith to understand'). This reflects the ancient biological misconception held by Middle Eastern and Greek cultures before the neuroscience of the brain was discovered.