A person who questions accepted beliefs is an example of a skeptic.
Origin of skeptic
- Latin Scepticus disciple of Pyrrho of Elis from Greek Skeptikos from skeptesthai to examine spek- in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- From Latin *scepticus, only in plural Sceptici (“the sect of Skeptics"), from Ancient Greek ÏƒÎºÎµÏ€Ï„Î¹ÎºÏŒÏ‚ (skeptikos, “thoughtful, inquiring"), from ÏƒÎºÎÏ€Ï„Î¿Î¼Î±Î¹ (skeptomai, “I consider"), compare to ÏƒÎºÎ¿Ï€ÎÏ‰ (skopeo, “I view, examine").