1. Dualism
Dualism, most famously championed by René Descartes, posits that the mind and body are fundamentally distinct substances. According to Descartes, the mind is a non-physical entity responsible for thoughts and consciousness, while the body is purely physical. This sharp separation has sparked centuries of philosophical debate, especially between dualists and materialists, who believe everything—including consciousness—can be explained physically. Despite scientific advances, dualist ideas persist in popular culture, influencing how many people intuitively think about the self and the soul. Learn more at the Stanford Encyclopedia of Philosophy.