What colour do You see?

Have you ever wondered if red is really red? or if blue is really blue? or if greeen is really green? What if what you see as red, I see as blue, or yellow? How do you know if the colours you see are the same as what everybody else sees? Sure, you ask somebody else what colour the sky is and they will say "blue"... but what do they perceive as blue? What if they are seeing green and just call it blue because to them green is blue? What if we all see colours differently but in kindergarten we are taught that this colour is green and this colour is red but we all see something different? Sure, we all call it the same name but do we all really see the same colour? hmmmmm? wrap your mind around that!