Good science requires distinguishing between "felt knowledge" and knowledge arising out of testable observations. "I am sure" is a mental sensation, not a testable conclusion. Put hunches, gut feelings, and intuitions into the suggestion box. Let empiric methods shake out the good from bad suggestions.
Robert A. Burton, M.D., M.D. (2008). “On Being Certain: Believing You Are Right Even When You're Not”, p.170, Macmillan