Are we sure that we are all great human brains?

Well normally we say we are the most intelligent creature on earth, are we? The question it self is the answer. We ask and what brain does is provide an answer. It's because human brain cannot say "i don't know what you are talking about." It has to answer and so it answers, "Yes."

Then in absence of absolute truth about the existence of the other intelligent creature who is asking the same question we answer that question as yes and we are all great human brains. But not yet, brain's gotta be categorized into three type: super intelligent, moderate intelligent and low intelligent.

But we all are less intelligent enough find out there are places we have not been, parts of human brain still unknown and so many species still unknown, so we could be or could not be greatest living creature on earth.