Now that Part I has laid out our goals, let's tackle the questions we've raised one step at a time. We'll start with the one I think is more complicated, "What makes me human?" as I suspect my humanity will be more useful to answering questions about my identity than the reverse. It might be helpful when reading this series to not assume that I am explicitly stating any one point of view as fact immediately, but rather attempting to be thorough with different ways to conceptualize and analyze the issue at hand so that we can find the one we might consider the best.
So when we ask a question like "What makes me human?", what do we take this to mean? For clarity's sake, let's phrase this for the moment as "What makes me a human?" as we do not seem to be using "human" here to describe us the same way we might use it to describe other things, e.g. "human skeleton" or "human folly."
We might approach and interpret the question this way: there are many things in the world which I can accurately identify as humans, but of course, there's only one me. So "Ryan" is a particular thing, but "human" is a universal category that doesn't exist in any one thing. So what is it about the particular "Ryan" that makes it fit into the category "human"? Well, it makes sense that whatever it is that makes me a human being should be the same thing(s) that makes all other human beings fit into this category. We don't say things like "Holly is a human being, but not in the same sense that Jordan is." We'd have trouble understanding what someone meant by such a statement, most likely.
So if we wanted to define what a human being is, we would probably refer to a property or set of properties defined by (let's say) scientific criteria attributable to all humans. Thus, we might restate our original question like so: "What are the properties of the particular 'Ryan' which make it a part of the category 'human being'?"
Now there have been lots of attempts to define "human being" and "humanity" with this and similar approaches. Rather than go through endless examples of this, let's discuss what needs to be true for this approach to actually work. We have asked ourselves, "What are the properties that classify individuals as humans?" For any definition or classification of human that uses this approach, we must be able to imagine absolutely no possibilities where:
a) something would be human without one such property, or
b) something would not be human despite the presence of all these properties.
It is important that we allow for hypothetical scenarios here, as they are what really show the limitations of any given definition. Let's take the scholastic definition of human as "rational animal." Given what we know about evolution, we should be able to easily imagine a new species of animal with Homo sapiens as its ancestor and the capacity for reason that we would not call "human." And so while "rational animal" may be a practical definition in that we could only use it to describe one thing that exists, it does not account for all possibilities. It would be like defining the genus Homo in terms of Homo sapiens because there is only one species within that genus that exists currently.
Speaking of evolution, this approach makes another very important assumption, namely, something either is human or is not. That doesn't seem to go in line with what we know, however. I propose another thought experiment to demonstrate this:
Can we go back far enough in our evolutionary history to find a human whose mother is not human?
I think this would be extremely difficult and unlikely, even without the part that requires time travel. Evolutionary progress seems to be more of a continuum than a sequence of stages. Would our criteria allow us to draw that metaphorical line which creates such a distinct categorical separation? Even if we wanted to talk about this in strictly biological terms, we still run into the notorious species problem, which seems to me to be the exact same problem faced when defining any taxonomic or categorical term.
These difficulties should be extremely relevant to us, and it is important to bring them to light before going any further in this investigation. For literally over two thousand years it was taken for granted that category terms had fixed boundaries and that any debate over these boundaries was not a sign of the insufficiency of this approach, but rather a matter to be settled with time. It was only in the mid-20th century that this idea came under serious questioning and attack in philosophy, anthropology, and cognitive science. Even though we often talk now of "gray areas," the idea that most things "either are or are not" any given universal term is still prevalent in the way we conceptualize, categorize, and organize the world we see around us. We create definitions that are useful in most cases yet are full of exceptions.
So what can we do without these fixed boundaries, you ask? That's the subject for Part III!