On the other hand questions lead to answers. Doubt tends to lead to experiments. When people start to doubt things they ask questions that lead experiments. Throughout the making of many innovations and inventions doubt led these experiments to find answers. The light bulb exemplifies itself as one of these innovative inventions. In fact Thomas Edison led his invention of the light bulb by trial and error. Questions lead to answers.
However, certainty leads to success. The Declaration of Independence stands as a result of success though certainty.