Philosophically speaking you can never verify anything through experimentation: in a controlled experiment you will use instruments and tools you need to trust (how do you know the microscope isn't lying?) and if you go through the process of trying to see if anything is confirmed, for a long enough time you will end up with the axioms of any scientific field, which are never verified (just assumed true).
You can prove negatives though, so thats something :).
You can prove negatives though, so thats something :).