"We don't know if Neanderthals count as humans, or if chimps do, because we can't agree on the defining features of a human" I don't think any scientist disagr

"We don't know if Neanderthals count as humans, or if chimps do, because we can't agree on the defining features of a human" I don't think any scientist disagrees that chimps aren't humans. The issue in question here is how far back in our lineage do humans go, vs. some other species. Given that evolution happens continuously, and not in a discreet way, it is completely impossible to objectively determine precisely when we "became" humans, something which is exacerbated by the fact that we're only looking at fossils. Perhaps, like porn, we should not try to define it further, but there's no question that, when looking at today's existing species, you know a human when you see "it".