The theme of this study is the philosophy of mind in Descartes, Malebranche, Spinoza, and Leibniz. It aims to demonstrate that the question of the nature of the mind is addressed by these authors from the outset within the context of an epistemological problem, and it is only through this that its peculiar profile emerges. What must the human mind be like if secure knowledge is to be possible? This is the central question posed in early modern rationalism. The authors of classical rationalism answer it in several monumental attempts by describing the human mind as something that is essentially related to God and His omniscience. In a radical continuation of scholastic philosophy, the visio beatifica, which allows the finite mind to partake in God's infinity, proves to be central.