Updated 2012 08 16 15:00 Z: see below
The media are very much in character this week, after publication of Eriksson and Manica's 'Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins' in PNAS and that of Leakey et al., in Nature, 'New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo.'
It's like a Bizarro world, or the curious story of Henny-Penny [A.K.A. Chicken Little]. The Sky is Falling! And it happens every time someone presumes to erect a new hominid taxon or publishes a contradictory interpretation of an extant archaeological or other dataset. The take-home message of the current headlines is something like
Holy Shit! We Didn't Breed with the Neanderthals After All! Or did we? How are we ever gonna know?
and
Fossil Hunters Change Their Interpretation of Human Evolution More Often Than I Change My Underwear! Maybe the Crazy Creationist Christian Supremacists are right, after all--there is no irrefutable evidence of evolution.
And, as far as I'm concerned, at such times science is the unintended victim of its own success as much as it is of its own failure. But how did it get like this?
I'll be the first to admit that many before me have sputtered on about the media and the public's attitude toward science, especially so-called soft, or social, science [e.g. anthropology & archaeology]. The human palaeontologists manage to escape the worst of the criticisms, but they're not completely out of hot water, 'specially amongst those aforementioned Christianists.
If I may, I'd like to turn the whole problem on its head and give it a subversive spin. A long time ago I wrote a synthetic piece on archaeological science. Brave hearts can find it here. In brief, while no one was watching [least of all the 'hard' scientists] a revolution of sorts has taken place. As Alison Wylie* puts it
...archaeologists can and do use fragmentary data to achieve an understanding of the cultural past in a way that positivist, empiricist theories of science are entirely incapable of comprehending..
And therein hangs a tale.
I don't expect many among you to be familiar with the root of Wylie's question. Suffice it to say that in the 1980s there was considerable, rancorous, disagreement between what was then the unfolding Post-Modern worldview and the practitioners of what Binford called Processual Archaeology [also known as the New Archaeology]. Before Wylie, Thomas Kuhn had been widely embraced for his historical, sociological study of what he termed Scientific Revolutions [paradigm shifts, he called them, and Binford and others saw themselves as the movers and shakers of a revolution--a paradigm shift--in archaeology].
By the time I arrived at UC Berkeley in 1988 it was all-out war in the literature. I found myself confronting what was prematurely deemed to have been the end of the so-called scientific project. Fellow graduate students were all set to forego what they thought of as science in favour of a research program based on the insight that no one is able to step out of their cultural and disciplinary experience to achieve the 'objectivity' espoused by most scientists. The quite erroneous conclusion seemed to be that 'anything goes' when it comes to understanding anything more complex than a light switch.
I shan't undertake a commentary on Post-Modernism at this juncture. I'd rather explain what I've just alluded to. As Wylie has tried to explain since the late 1980s, as others have attempted to do with varying degrees of success, the 'problem' of science isn't so much the culture or [sometimes more importantly the gender] of its practitioners, the problem is the way science, itself, is understood. It almost seems old hat to me now, but it's worth remembering that for about, oh, four hundred years science was seen as a pathway to truth and an engine of 'sure and certain' knowledge, in opposition to superstition, personal experience, and supernatural explanations of physical phenomena. But you must understand that when Wylie refers to 'empiricists' she's not talking about people like you and me, who rely on empirical observation to make knowledge. She's talking about a way of thinking about science that for a long time maintained that science was all about 'sense' data.
Those 'sense' data are presumed to be impervious to bias, and can be perceived by anyone--unlike, for example, a trance, or an epiphany, which can only be experienced by one, or a very few, persons. Science positioned itself against the Church almost from the beginning, which as everyone knows, spelled trouble for the likes of Galileo! So, for about 400 years, until some time after the middle of the 20th century, science had been thought of as a means of examining the physical world in a way that precluded interpretation, and instead made knowledge by building upon observation that was immune to the vicissitudes of intersubjectivity, bias, and speculation.
Unfortunately for most people alive today who call themselves scientists (social or otherwise), the empiricist train has left the station. But they're unaware that they've been left stranded on an empiricist platform. I'll give you a straightforward example of the difference between 'empiricist' science and what Wylie refers to as a 'realist' science that can, and does, explain the successes of the last 400 years as something well beyond the collection of observations and the creation of physical 'laws' [e.g. Gauss's]. My simple example is this. [By the way, this is an example taken from the voluminous philosophical literature about science, and refers to a rather big name in the history of science. But I won't spoil it by telling you who it is.]
Empiricist A plucks the strings of a guitar. Empiricist A hears a sound. But Empiricist A, being the good little empiricist that he is, can't bring himself to say that plucking the string 'caused' the sound, since he was unable to 'observe' whatever it was that translated the pluck into the sound. [It sounds ludicrous to me. And I'm sure it does to you. But that is precisely the way 'science' has been practiced for centuries.] Empiricist A proposes a physical 'law' to explain the relationship between the pluck and the sound. However, his law has nothing to do with what occurs when the string is plucked, and its vibrations ripple through the air such that he could hear a sound. Instead, his law, the Law of Constant Conjuction, 'explains' the sound by proposing that whenever a guitar string is plucked it is followed immediately by a sound. That is the best that an empiricist science could do in the days before fancy instruments made it possible to break down the string-to-sound sequence into smaller--observable--bits long before oscilloscopes made it possible actually to aid in the empiricist understanding of acoustic phenomena.] But long before empiricists figgered out a way to explain the guitar sounds in a way that would fit within their uber-rationalist framework you and I had 'modelled' the process after the motion of the water after a stone is tossed into the middle of a pond, when a circle of ripples [waves] races across the surface.
What Wylie is telling us, and what most of us always knew, is that there is more to making scientific knowledge than 'sense' data. Long before bevatrons and tevatrons and Large Hadron Colliders smart thinkers had modelled the motion of electrons in an atom by analogy to planets orbiting around stars. Yet, such 'models' for the way things work are anathema to empiricists. You can't make knowledge about anything you can't see, hear, taste, touch, or smell.
By contrast, a 'realist' view of science is that we may never see, or otherwise perceive, the motion of electrons in an atom. But the knowledge we have, based on the planetary model, is no less scientific, it's no less successful as a means of understanding physical reality, than the Law of Constant conjunction. Instead, it's actually better, because it's sensible, and realistic, and is the best way we have of interpreting the observations we can make. And if you don't believe me, try standing next to an atomic bomb when it's detonated. Models or not, I think those pesky physicists have figgered it out!
Getting back to the reason for tonight's diatribe, the Frantic Press and the Far Right [Far Out] Christian Supremacists, and an unbelievably large number of your fellow citizens think that science has failed, or is not to be trusted when someone like yours truly interprets the archaeological record in a way that flies in the face of decades of received knowledge, or someone suggests that we can't state unequivocally that the Neanderthals and modern humans interbred, or that there's [yet] another species of hominid in East Africa that co-existed with the two others we've known about since the 1980s. That way of viewing science--as right or wrong, with no gray--is the result of very influential people who cleave to a failed view of science. And from here on out, it's not gonna be our problem. Now is it?
* Wylie, M. Alison. 1982. Positivism and the New Archaeology. PhD dissertation, History and Philosophy of the Social and Behavioral Sciences, State University of New York at Binghamton.
Update:
I'm fairly certain that I can't be as eloquent or as expansive as one needs to be when engaging in discussions of this sort. Be that as it may. A comment on the above has compelled me to try saying it a different [and far more brief] way than the above. Here goes nothing!
The point to be understood is that "pure" [or "hard"] science was never what it proclaimed itself to be, and that archaeologists and what many call "pure" scientists make knowledge using the same kind of reasoning, by reference to the empirical realm. Moreover, the empiricist "account" of Science was never a "realistic" description of how scientific knowledge is made. A narrow, Empiricist, view of science is, in very "real" terms, incapable of accounting for some of the greatest successes of Science over the centuries [e.g. no one's yet 'seen' gravity, but we know it exists; no one's seen the past, but we know it exists AND that we can make reasonable sense of it--the past does not exist in the empirical world--an idea that was (and still is) anathema to Empiricist accounts of science].
Hence, a 'realist' view of science, which recognizes that we don't make knowledge ONLY by Empiricist 'rules of engagement', and which says that we can create knowledge of the physical world even when we can't put our fingers on the 'sense data', or can't describe our inferences in an IF A, THEN B equation...a realist view of the creation of scientific knowledge is a far more accurate account of how science works than that of the Empiricists.
Ipso facto, forget the dichotomous (and divisive), and specious distinction between "pure" or "hard" science and what we so-called social scientists do. We're all in the same game, epistemologically speaking! And it really doesn't matter if no one else 'believes' what I'm parroting here--you can't change what is, you can only be hampered by what you think "IS" if it leads you to constrain yourself in irrational ways. That's where the New Archaeology fell over--its goals were 'realist' but its methods were 'empiricist' and it couldn't get past that untenable tug-of-war.