Originally Posted by Zyr

How do you know blue is blue? It's blue cause you see it being blue? What if you see diffently to someone else? Maybe you've been told it's blue, but actually it's red, and it's all a life-long joke on you?

There are absolutes, the only one I can think of at the moment is existence. I exist. You exist. Well, maybe you don't, but you can't deny your own existence. It is the absolute. There are others, but you can't really know them unless you exist.

I plan to make a thread based on my own thoughts on this, but it's not ready yet.