Quote Originally Posted by MrShrike View Post
This is basically the same question as which came first: the chicken or the egg.

The answer is, of course, the egg.

Once upon a time, there was a creature that was not quite a chicken and from that not-quite-chicken came a thing which was without a doubt an egg. That egg hatched and the creature that emerged was what we call a chicken.

The reason why we can say this is because a chicken and an egg are both things we can define. So we can point at some thing and say, yes that it a egg or no it isn't etc. Or similarly, yes that is a human being, or no it isn't. We can argue and quibble forever and a day with each other over the exact definition you want to use, but the fact is, if you have a word for it, that word has a definition, and historical entities either fit (or fitted) that definition or they don't/didn't. This is true even if you don't know if a given specimen fitted that definition or not, so we don't have to know exactly WHICH chicken egg was first, to know that there was a first chicken egg, or that the egg came before the chicken.
I had this in mind when I wrote that.

A chicken is a creature which fits a certain biological profile. A human, similarly. A human, then, is presumably something with a sufficiently similar biological profile to ours, but I'm saying that there is probably more difference between the biological profiles of whatever "first human" you want to identify and us than there would have been between those first humans and the previous generation.

I don't know how to say this succinctly and I'm not all that comfortable with the terminology, so am I making any sense?