In the movie Star Wars, Master Yoda told Luke Skywalker “do or do not, there is no try” after he told Master Yoda that he’d try to do what he said. Before Star Wars, the way we said this was sink or swim.
What does sink or swim mean? Imagine you are on a boat that sinks and you have nor life preserver or you cannot hold on to something that floats. You have two options: you either swim to safety or sink and become fish food.
The phrase sink or swim is used when we face a situation where success is necessary for us to get through a challenge. If not, we face failure, there is no middle ground.