This is a post by Dario Mortini (University of Barcelona).

Simple ‘outright’ assertions serve a wide range of familiar communicative purposes in our daily lives: from giving directions (‘The Sagrada Familia is up that street to the right’) to sharing novel and interesting facts about the world (‘The new bakery in the neighbourhood sells apple cake’). However, we are not always well-positioned to make outright assertions. When uncertainty looms, we must settle for something weaker.