A related article is titled uncertainty.

Certainty is the absence of all doubt. Something is certain if it is so clearly established or assured that skepticism could not exist. Philosophers have struggled for certainty, but have had many difficulties. Meditations on First Philosophy is a famous pursuit of certainty by Descartes. Contemporary views of knowledge do not demand certainty, but rather a "justified true belief". Epistemology is the study of knowledge, certainty and truth.

See also

• I think therefore I am - often thought to be the only certain fact
• On Certainty by Ludwig Wittgenstein
• Almost surely
• Infallibility
• Postmodernism

References

• http://www.bartleby.com/61/41/C0214100.html