> In the end, the answer is approximately the same: the father of the first modern human would have been a different hominid species. The question was not abou

> In the end, the answer is approximately the same: the father of the first modern human would have been a different hominid species. The question was not about the father if the first human (regardless of how you define human, as long as you use a sharp definition). I had already told my daughter that the mother (and implicitly father) of the the first human were belonging to the prior species in the chain. (For me "human" was used as Genus Homo, but it doesn't matter if one uses homo sapiens sapiens instead) The difficulty of the question came from my daughter asking who would be the father of the CHILDREN of the first human (assuming the first human was female). Either that male would have to still belong to the previous species, or have been born independently of her as human, somewhat after. Given that the second option is very unlikely. If we set sharp enough criteria for qualifying as human to be able to separate different members of the tribe these individuals lived into either human or non-human, the probability of the first two who qualified would arrive so close in time and independently, is probably near zero. In other words, we must assume that if we insist on splitting indivuals into the categoris of "human" and "not human" at that specific point in time, most likely the father of the children of the first human must have ben non-human. Also, it would be very likely that even the children may have been non-human (or it may be tha the first "human" didn't have any children at all). In fact, it could be a 100 or a 1000 years before another individual was born that qualified according to whatever definition of "human" we pick. And this is when I realized that: > the biggest problem here is that "species" don't actually exist. Not only is any definition of "human" in some way arbitrary, the very act of creating such a definition leads strange contradictions such as above. Intuitively, all members of the tribe that brought us the first humans, would have appeared to us as all being EQUALLY human, had we had some way to observe them directly. To draw some red line between individuals of that group makes no sense. (In fact, being in the same tribe, these individuals would be closely related, and so much more similar to each other than two randomly selected modern humans living today would be.) Also, it doesn't help to just create a new category, since the problems at the boundaries will be precisely the same. In other words, the only thing that makes sense, is to not assign categories of human vs non-human to these individuals at all. The closest thing that would make sense would be to assign some "degree of human-ness". Let's say that the first individual with such human-ness would have a human-ness score of more than 50% would have a score of 50.1%, while the average for the tribe would be 49.7% at the time. By thinking of this transition as a real (as in floating point) number, instead of as a boolean, the problem goes away.