In fact that is an essential part to how theories are evaluated. Not just by what they explain, but by what they predict. Most theories on physics are evaluat

In fact that is an essential part to how theories are evaluated. Not just by what they explain, but by what they predict. Most theories on physics are evaluated this way. "We theorize that light is a particle, which would explain these properties of light, and means we should expect to see these other properties of light if we test them." If further observation of light matches those properties you predicted then that's pretty good evidence that your theory is on the right track.