Debate: Should abortion be made legal?
Side: yes

The gist of my suggestion was merely to use scientific terminology; I thought "fetus" would suffice to highlight the basic differentiation I was after, but if you wanted to be more particular I wouldn't object. "Proto-" is a prefix which functions differently from the other modifiers (i.e. child, teenage, adult); it indicates something prior to human, whereas the others qualify a type of human. These were soft suggestions anyways, and I don't feel particularly driven to defend them since my position on legalized abortion isn't contingent upon the language we use. My original objection was merely to the logical invalidity of concluding that because we might call A life then B must be human life. Beyond that, though, I do have a general argument which you have begun to identify. This objection is not, as you suggest, against arbitrary ascription; I think all ascription is arbitrary insofar as it merely reflects the conceptual understandings our preferences cause us to associate with things, but I have no objection to this (that would be futile). Rather, my objection (and frustration) is with people treating ascription as non-arbitrary and thereby as a sound component in an argument on the legalization of abortion.I regard the semantic dispute about what constitutes (human) life as a distraction which takes its relevance only from the belief that if we should call something by a particular name that this should somehow alter how we treat it. This is grounded in further arbitrary association of the terms in question with ideas about what it means to be "human" or "life"; these, too, cannot advance on objective merit over any competing conception. The real issue at hand is how we treat that which is inside a biological female relative to how we treat something outside the same; I do not think that the language we use is material to answering that question. Pointing out the subjectivity of others' positions is a particularly effective approach when people operate as if they are expressing objective truths, which is fairly often here. I also do not understand why you seem to find this questionable behavior on my part. I use this approach frequently because it is consistent with my philosophy as an epistemological and value nihilist. I have no issue with people arguing from subjective premises, and where someone identifies that they are doing so in order to advance another argument I can treat the premise as accepted in order to analyze that argument (or ask them to entertain if they think it still holds under my premises). However, most people do not treat their subjective premises as subjective and I find it acceptable to press them on that (as well as generally impractical to try having the aforementioned form of engagement). I do not hold any proscriptive positions, which is why I do not tend to advance affirmative positions of that nature since many topics here are propscriptive. I am not afraid to express my own preferences and opinions. However, I do not treat them as grounded by objective premises because I do not think we can know of any objective premises with certainty (excepting that something exists, or possibly some other similar tautology). When I advance a position it is out of my preferences, and these I will argue for. I do this either from mutual premises (which are rare), or by adopting the opposing premises and arguing from them as possible.