If we consider a relation of things through relativism, there is no way we can ever know the truth. On the other side, the kind of knowledge we have is subjective. We feel things at a different intensity, but it does not mean that knowledge becomes singular. We know and understand concepts without confusing them. For example: hot and cold means a variation of temperature. There is a variety of intensity in the perception of the word, but it cannot be confused with another concept like light.
We can measure reality in relation to our point of view and this fact is as close as anyone can get to the truth. If realism was the only way to know things, we wouldn’t be able to speak of what we perceive. There would not be any language and everything could be allowed without our knowledge. We would not be able to speak of what is a human, and how to treat it, everything would be reduced as animals perceive it: to gain their own benefit or danger. Men would become an object and not an intelligent being capable to improve himself. We wouldn’t be able to appreciate beauty, to know the truth and to want good. If knowledge reduces man to what is relative to him, he will lose the most important trait that constitutes him: to transcend and be happy.
Life withuout meaning is intolerable; the existencialist philosophers talked about it. A life without meaning produces indigestive problems: nausea. We must know why we live for, not because is good but because we want it.