An adult sleeping peacefully on a bed with white pillows and linen.

What if you’re dreaming?

The dream argument says you can’t tell dreaming from perception, so perceptual “knowledge” fails. Evidence may underdetermine every theory.

Skepticism and the Limits of Knowledge

Detailed macro photo of Julia Heliconian butterfly perched on a rock with vibrant wings.

Nature’s built-in fog

The uncertainty principle and chaos’s butterfly effect block perfect prediction. Some truths stay out of reach in practice.

Skepticism and the Limits of Knowledge