Magenta DOESN'T exist?

Magenta does not exist on the light color spectrum. Craaaaazy, huh?! As you may know, our eyes have three sets of cones to sense color: Red, Blue, and Green. Normally when two colors are mixed, the eyes sense the color in between those two colors on the spectrum. So when the Blue and Green cones sense light, we see Cyan. When the Green and Red cones light up, we see Yellow. But whats between Red and Blue? Green! This is where it gets interesting. Our brain knows we aren't seeing Green because the Green cones in our eyes are not activated.   So our brain makes a color up, and that color is Magenta!