What makes someone human?

[Armchair Academic]

Like in any type of logic, reasoning, or science, attempting to break something down into its most fundamental properties always results in a jumbled mess that doesn't really make any sense. As interesting as it may be, we neither have the logical prowess nor the natural predisposition of truly understanding the individual components of anything this complicated. It almost seems necessary to approach things, such as human-ness, with a gestaltian view. Otherwise, you begin to ask seemingly silly questions, albeit interesting and still worthy of discussion. Questions such as:

Are vegitative people human?
Are babies human?
Feral children?
Schizophrenics?
Anyone with a mental disorder?

And:

Are sufficiently advanced A.I. human?
Can the universe be looked at as a sentient and human entity?
Are individual cells/DNA human?
If they exist, are intelligent extraterrestrials human?

[satan pizza]

I've always defined this in my head as a person is human if they have experienced human consciousness, or 'life'.
We can't necessarily prove that rats, using your example, have a consciousness, at least not in the sense that a human does. The human mind is what has really set us apart from the other life forms on this earth. For the 'life' aspect, for example, I do not believe that the fetus is alive because it has not experienced true consciousness. Yet at the same time someone who is trapped in a coma is still 'human' or alive because at one point they were able to feel and think and communicate as a human does.
Though if we used this sort of definition then we'd have to go into, "What is consciousness?"
That is a trickier one to answer, I think.

[Avgvsto]

Im not sure, i'm depressed