Is it better to have more certain knowledge about less perfect things or less certain knowledge about more perfect things? The former is science and mathematics; they give us knowledge about numbers and planets, which are things smaller than ourselves. The latter is religion and philosophy. The bigger the questions are, the less clarity and certainty we have about them. To say we should only believe and discuss what can be proved and known with certainty would strip away philosophy's most important questions, as well as those asked by religions as well.