Is it possible to define a human being without implying any sort of metaphysical hypothesis? It seems to me that every statement one can make to define a human being must necessarily imply some metaphysical hypothesis.
I've tried to think why this must be necessarily the case and I believe that this due to the fact that language itself builds upon metaphysical hypotheses we all share unconsciously and from which it can't be divorced.
"Is it possible to define a human being without any any metaphysical hypothesis?"
Some (Proponents of scientism) might strongly disagree with what I am about to say, but I will support my claims in the upcoming paragraphs.
Yes, It is impossible to Define a human being without any metaphysical postulation.
Let me explain: In general, when we say "define" X, for the lack of a better name, we intend to ask what does it mean to be X. Whoops, did we just tread into ontology?
Since the very question is ontological, its answer would, by definition (pun intended), be metaphysical. "Why is that," you ask? Because ontology is a subset of metaphysics. Let us take a tangible example; let us define a car. "What is a car," can be equivalently paraphrased into "what does it mean to be a car." It should be quite clear after the paraphrase, that the question is asking nothing but what are the "essential" attributes instantiated by a car.
That said, essentialism is not needed. I just used it to give you an example. There are two broad catagories of theories dominating contemporary ontology: Nominalism, and Ontological realism. Both of these catagories have numerous particular theories within.
However, one thing we can be certain of: the answer to the question "Define X," is necessarily metaphysical.
I hope that answers your question.
You seem to think a complete 'final vocabulary' definition of being human is possible. Consider Rorty's challenge to this.
Plato famously attempted to define humans, and had some trouble. He was really trying to contrast humans to other categories and types, seemingly as a proxy for essence. But as Sartre put it "Mankind has no essential nature" ; existence is before essence, we are what we do before any process of abstraction, and what we do has the final 'word'. And as Darwin showed, has always been mutable.
You are seeking a transcendent universal final definition. Neccessarily, that would only be possible using metaphysics. But many avenues of challenge are available to whether that is a meaningful or even possible approach. Definitions have to be relational, contingent. Even mathematics is a language of abstractions, only relatively transcendent/abstract from experiences, as far as our (or other beings') capacities allow seeing.
Human means Earthling, a minimal concept not rising to the status of hypothesis.
The word human ... originates from a Proto-Indo-European word *ǵʰmṓ "earthling" < *dʰéǵʰōm "earth". Compare Latin homo "human" and humus "earth, soil".
