De Anima (On the Soul)

De Anima (On the Soul) by Aristotle explores the nature of living beings' "soul" or essential life principle. He argues that the soul is the form or essence of a body, giving it functions like growth, perception, and thought. Different types of souls exist: plants have a nutritive soul, animals have sensing and mobility, and humans possess rational thought. The soul isn’t separate from the body but is what makes a living organism alive and functioning. Aristotle’s work emphasizes understanding consciousness and life through the relationship between form and matter, shaping ideas in biology and philosophy for centuries.