And the first time we observe a photon that doesn't travel at lightspeed in circumstances where it should, then barring error it will have falsified what we know of the speed of light. Science, in a word.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'