Can we turn to science for an answer? Some paleoanthropologists identify the category of the human with the species Homo sapiens, others equate it with the whole genus Homo, some restrict it to the subspecies Homo sapiens, and a few take it to encompass the entire hominin lineage. These differences of opinion are not due to a scarcity of evidence. They are due to the complete absence of what sort of evidence can settle the question of which group or groups of primates should be counted as human. Biologists aren't equipped to tell us whether an organism is a human organism because "human" is a folk-category rather a scientific one.
If science can't give us an account of the human, why not