It's only impossible if you think it is...

The more Theremon thought about his chances of finding her, though, the less impossible the task seemed. And after a while it began to seem quite possible indeed.
As he endlessly reevaluated things, finding Siferra went from seeming impossible to merely unlikely, and from unlikely to difficult, and from difficult to challenging, and from challenging to feasible, and from feasible to readily achievable.
- Isaac Asimov; Nightfall