Re: What archaeologists Do: Feedback
Now that is actually an interesting question. First, I would say that this is not necessarily true and I don't think it is true for me. However, maybe some context might help.
100 years ago, anthropology more broadly accepted the idea that there were laws of human nature, etc., and set the goal of identifying those laws. This, of course, was "positivism" and part of the nomothetic kind of thinking. The main theoretical themes of the time were defined in terms of "functionalism" or structural functionalism where all parts of a society from language to the shape of houses were assumed to reflect some central, under-lying thing. The real question was whether the object of study should be the society, which is the people on the ground as it were, or the "culture" which here would be something almost above and outside the people and their actions. The problem was (and is since this debate actually continues) the question of whether something like "culture" really exists because this sets "culture" up as a kind of metaphysical thing that exists independently of people and what they do. Archaeology was a part of anthropology at the time, more completely in some ways, but considered kind of subservient or lesser because it didn't deal directly with people and what they thought and did. Part of this was certainly methodological. Related here was an old bias where archaeologists collected tons of stuff and had to deal with all of that to find the things that might be most informative. And, well people seem to be more fascinated with big flashy things like gold, idols or big buildings, etc. (Again, rhetorically, what interests people more, Egyptian mummies and pyramids or the life of the average Joe in ancient Egypt?) Part was a more theoretical problem (i.e., rhetorically, why would houses or pots be any less of a reflection of society or culture than language or kinship?) And of course, there was certainly plenty of disciplinary bias (still around of course).
To cut to the chase, first I would be very cautious about even suggesting that there are "facts" here or anywhere. "Facts" imply certain things have potentially dangerous implications. I would say that we collect data of certain kinds but exactly what that data tells us and what it can be used for is never really fixed but is very dependent upon the kinds of questions being asked and the kinds of inferences to be generated.
However, the real crux of the matter here is in the question of "abstract principles". If by this you mean something along the lines of "laws of human (or other) nature", then the question really, IMHO, is whether these really exist. Since I am relatively open minded and liberal, I acknowledge that there may be some value to hypothesizing certain potential "abstract principles" and looking for ways of testing that kind of hypothesis.
For myself, however, I believe in a different approach. For me, the question is one of collecting "data" and then trying to figure out what this is data of, i.e., what exactly this data tells us. We do have plenty of cautionary tales, including what post-modernists talk about, that indicate or at least suggest that we don't really know what the "abstract principles" are or should be if they exist (and they may not). In other words, assuming that "abstract principles" exist or that we know what they are (as valid, scientific hypotheses) may be assuming that which should be under investigation. I certainly believe in looking for regularities across time and space and I believe in using multiple kinds of data (i.e., not just archaeological data). However, what I have found is that by taking a closer look at the "data" I can learn different things.
Just by way of example, many people who examine animal bones on an archaeological site use this "data" to talk about diet or perhaps the domestication of animals. Some of these debates are interesting and have their place in addressing some questions. While I do not interfere in these kinds of questions (research agendas), personally I am more interested in the distribution of animal bones across a site because from that I may be able to infer patterns of food sharing form which I might be able to infer social interaction patterns. Or sometimes I am more interested in ritualistic patterns which can include non-food animal remains. Same data, different uses. Thus, I do not really start out trying to look for or test specific "abstract principles"; I prefer to see where the data leads me and look for the unexpected, not just try to confirm or refute my a priori assumptions.