Philosophical skepticism is a school of thought that questions the possibility of certain knowledge. Skeptics argue that our beliefs and perceptions may not accurately reflect reality, leading to doubt about what we can truly know. This perspective encourages critical examination of our assumptions and the evidence supporting them. Historically, figures like René Descartes and the Pyrrhonists have contributed to skepticism by challenging the reliability of sensory experience and reasoning. Philosophical skepticism serves as a foundation for various debates in epistemology, the study of knowledge, and encourages a cautious approach to claims of certainty.