When one person looks at something in the real world, ie book, table, cat etc. are they really seeing what is there or something that their experience tells them it should be? Do any two people see the same thing in exactly the same way? Why?
You’re thinking too hard. Drink a glass of water, go to bed, and start counting sheep… 
I think people see the light reflected off of an object. Matter itself has no colour, but when it absorbs light, and gives some off, it can be coloured, and therefore seen. This kind of applies for black things too, I guess, since we see the absence of reflected colour when everything around it is reflecting colour. I suppose we don’t “know” something is really there without touching/manipulating it somehow, though it’s ingrained in our brains at a fairly young age that we see tangible objects (matter).
Ouch. too much thinking. Enough.
