of Peter

Lately, I have been trying to come up with an answer to the question, "What are the essential characteristics or qualities of being human?" For instance, a red ball has essential characteristics and it has non-essential characteristics. An essential characteristic is that it is round (with the exception of maybe a football, but for the sake of argument lets ignore that for now). However a non-essential characteristic is the fact that it is red. The ball would still be a ball if it weren't red and was instead blue, but the ball would cease to be a ball if it had a pyramid shape or if it was a cylinder. Taking that same concept over to human beings, what makes a human a human? What are the essential characteristics of being human? I think that this is an important question to ask for a number of reasons. Unfortunately though, because of time I have to neglect the reasons and leave this post at just the mere question for now. I would appreciate any comments that would help me think clearly about this question. I don't think that I have an answer to it myself at the moment so I could use all the help I can get.