Uncertainty, doubt, dubiety, skepticism, suspicion, and mistrust mean a lack of sureness about someone or something. Uncertainty may range from a falling short of certainty to an almost complete lack of conviction or knowledge, especially about an outcome or result.
"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science."