No philosopher is without talking about the human soul, because it is the closest thing to us, and to that closeness it is extremely mysterious. Whenever thinkers imagine that they have increased knowledge of it, reached the truth about it, revealed its secret, and known its essence, then they find that knowledge to be a mirage and the essence to be a stunning appearance. To this day, we are still where Socrates, Plato, and Aristotle were, and even more distant from the truth. Therefore, modern science neglected its request, and contented itself with analyzing psychological phenomena, leaving the field of essence to philosophers to follow the path to in the hope that one day they will reach the truth of the soul. Ibn Sina sought knowledge of the soul since his early youth, because "whoever knows himself knows his Lord." Ibn Sina and his theory of the soul had a great influence in the European Middle Ages. It was transferred to Latin and spread widely among European philosophers. European thought was subject to his influence from the twelfth century until the seventeenth century, when Descartes appeared and took from Ibn Sina his proof in proving the existence of the soul. . As for the impact of Sinai psychology on Islamic philosophers, it does not need evidence, as the later scholars acknowledged his leadership and called him the main sheikh, and they followed his example in most chapters of psychology.