Sorry to disappoint, but it's probably Kant who gave a name to it - noumenon as what's behind the phenomenon, what we can perceive, aka know. And no, I don't think he used the same words you did. And it was probably described before, too, but I personally just know of Kant talking about it.

Anyway. Those who always have to agree with you are not your friends. Those who can disagree with you are. All the data in the world doesn't mean a thing if we only interpret it our way, for sure. Data is neutral, we are not. We don't even have to know what we're looking for, as we solve that problem unconsciously and find results we ourselves think to be totally unbiased. That's why it's so important to keep disagreement around, not only to self-indulge in thinking that we're better by disagreeing, but to be able to consider the other side, to see the world from their eyes. Taking a step away from the egocentric view, even for a minute.

Honest, rational disagreement, as opposite to emotional disagreement, can create middle grounds. But in a system based on emotions, quickly manipulated to buy this and that, to have quick, uninformed opinions within minutes that fade as quickly as they were invented, will not allow real disagreement. Only more emotions.