Black and white, age old question?

So after learning about how color is light reflecting off of a surface creating specific wavelengths, I also learned that White is therefor created by the total reflection of light and black is created by the total absorption of light. This brought back nostalgic memories from grade school when i had this very strange debate with a classmate on wether or not black and white we're considered colors. Are they? Because white is not a specific wave length creating hue, nor is black.  But also theoretically you can mix a black. So what is the answer to this flustering question? After days of pondering, I have finally determined that although theory can offer a slight direction to this enigma; the final answer truly lies within the eyes of the beholder. I personally consider black and white to be colors, simply because they can used to ad tone and visual language just as the other colors can.

But i guess you can say that this question is not just black and white, but shades of grey!