Introduction to Philosophy

On Skepticism

0.01h 3mJanuary 16, 2026

In lecture five, we encounter the philosophical tradition of skepticism, examining arguments that challenge our ability to know anything or have reasonable beliefs, from ancient Greek and Chinese philosophers to modern thinkers. We analyze five main skeptical arguments—illusion, comparison, variability, the problem of the criterion, and logical paradoxes about truth and knowledge. Our discussion concludes by considering the skeptical recommendation to suspend judgment for peace of mind, while noting the fascinating self-referential problem that skeptics cannot assert even their own conclusions without contradicting their position.