We absolutely must leave room for doubt – or there is no learning and no progress. And a question requires doubt. People search for certainty – but there is no certainty. People are terrified; how can you live and not know? It’s not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge. And you really don’t know what it is all about, or what the purpose of the world is, or a lot of other things. It is possible to live and not know; we are constantly looking for answers. It is better to live and not know than to live having only an illusion of knowledge.
… Richard Feynman.