We've been taught that, to prove that a thing is true, we should point out what's true about it.
However, we can learn much more about why something is true by trying to disprove it first. If you think something is true, try as hard as you can to prove that it's false.
Disproving a theory is core to the scientific method. Only when we validate that something cannot be false, we come closer to proving that it's true.