An assumption is a mental leap you take without looking around first.  They're also taken for granted, and it's this easy-going acceptance of them that contributes to much of your anxiety. I would never trash assumption itself because it serves a critical role.  It can help you make decisions when you don't have all the facts, and also helps to remove mental hurdles that could otherwise complicate decision making.  For example, when you're driving down the highway you have to assume, to some extent, that other drivers aren't going to run you