Well I don't know exact rfrences in the canon to what a 'human' is, but hve seen philosophic descriptions which tend o ignore the phisicl aspect as this an cause biological humans to be considered inhuman an example of this is views of many europeans to africans and other aboriginal peoples when they first encountered them (so to speak in some cases) or the so called vegetables due to mental capaity, either from a degeneration from atural causes such as dsease or trauma, or a birth abnormality.
to clasify a human, o more precisely what a human is, is incredibly difficult especially when you considder (as must be) all he variations a bioogical human has both physically and mentally, would you cosider a psychopath to be human, or someone with Bi-polarefective disorder, or other psychological probem? or would you counider someone born with no legs human or missing other physical attributes common to humans, human? and what if they had extra limbs or a severe ondition such as elepant man, or other the man who is turning into a tree (as the program described him)?
Blog, Suttas, Aj Chah, Facebook.
He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them.
But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion …
He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.John Stuart Mill