What makes a human being... Human?

really human is just word like no other the only thing that matters is that we have consiousness

probably consciousness and self awareness, or our sense of morality, our freedom of choice and the way we communicate. empathy, curiosity, innovation.. i mean it cant just be one thing, its a jumble of things that make up a human :-)

Merely existing, I suppose.

I would say there are a few concepts that are objective truths in our reality that relate to what makes us human as we understand it;

Logic, Morality, and Wisdom.

Logic; The structure and laws we are governed by. Independent of belief and culture. Mathematics is a good example of this, a system we discovered and translated into a more abstract language readable by humans.

Morality; We recognize things that are good even when they go against survival instincts and what would benefit us in the short and long-term. Sometimes doing the right thing is just the right thing, even if it ultimately harms you.

Wisdom; A little bit of both of Logic and Morality. Knowing when to speak and when to stay silent, choosing mercy over vengeance even when both are justifiable. This is human endgame, to obtain wisdom. Not wealth, love, or assets, but wisdom.

Being made in the image of God helps.