On synesthete.org, there is a test you can take to prove that you have synesthesia, scientifically. For all the marbles. No more can anyone can doubt you, like they often do. It is an empirical test that can quantify if you are making up your “ability” or if you really do have the rare, neurological condition. The test is simple. Pick what kinds of synesthesia you have, and then choose what color is associated with whatever character/attribute appears on the screen. Below is a letter I wrote to the admin of this site, after attempting to take the Synesthesia Battery.