Sensory Perception and Its Philosophical Foundations in Avicenna and Leibniz

Due to its crucial role in acquiring knowledge, sense perception and its philosophical foundations have consistently been among the major topics in the history of philosophy. Avicenna, as a peripatetic (Aristotelian) Muslim philosopher, dedicated special attention to this problem. He advocated the unity of the soul despite the separation and multiplicity of the soul’s functional powers, leading him to posit an interaction or correlation between sensory and intellectual faculties. In the modern era, characterized by an emphasis on reason (intellect) and a perceived separation between reason and experience, Leibniz took a different approach. Drawing on his extensive knowledge of scholastic and ancient philosophers, he sought to reconcile elements of both old and new philosophies in forming his metaphysics. He based his metaphysical framework on select principles from Aristotelian logic but developed a unique theory regarding the unity of sensory and rational faculties. This paper aims to examine and compare these two philosophical viewpoints. Both philosophers held that it is impossible to fully grasp the truth of sensible objects, as knowledge is limited to understanding the properties and accidents of objects rather than their true nature. However, they diverged in their philosophical thinking, rooted in their respective worldviews and their stances on unity and plurality. Consequently, they both acknowledged the necessity of sense perception and the experimental method in acquiring knowledge, while simultaneously emphasizing the importance of reason and rational methods.