Like postmodernism, postprocessualism has a relativistic view of and is largely based on a critique of the scientific method of processual archaeology.
Postprocessual archaeologists were jaded with the deterministic and functionalist views of processual archaeology and feel that their new movement is the next step after processualism. In this way it can be seen that the name postprocessualism, first coined by Dr. Ian Hodder, its first and major proponent, has a dual meaning. The first is an engagement with postmodernism, its parent theory, the second is its emergence from processual archaeology (Hodder, 1986).
The general critique involved in postprocessualism is that archaeology is not an experimental discipline, which makes it highly vulnerable to attacks that it is not objective enough. The postprocessual archaeologists claim that, for the most part, since theories on cultural change cannot be independently verified experimentally, what is considered “true” is simply what seems the most reasonable to archaeologists as a whole. Since archaeologists are not perfectly objective, the conclusions they reach will always be influenced by personal biases (Trigger, 1989:379). A concrete example of this is the patriarchial underpinnings of most of archaeology until the latter half of the 20th century, wherein questions on the role of women in the cultures and systems under study were not asked. Postprocessual archaeologists state that personal biases inevitably affect the very questions archaeologists ask and direct them to the conclusions they are predisposed to believe.
While this idea may sound vague, it has definite consequences in the actual practice of archaeological fieldwork. In order to collect data and analyse it, the archaeologist must first decide which questions he or she wants to ask. Given that typical digs will cause hundreds of thousands (or perhaps millions) of artifacts to be recovered and analyzed, and that the cost of reanalyzing artifacts is prohibitive, the question of categorization and analysis techniques must effectively be posed prior to an excavation or survey starting. These techniques will often reveal biases.
Some postprocessualists believe that this means we can never accurately reconstruct the past, so why try? They advocate the use of archaeological data to produce historical fantasies. "Why not?", they say. "It's just as likely as any other explanation archaeologists can offer." Some also argue it is perfectly allowable to use archaeological data to support personal political and social agendas (Trigger, 1989:380). They perhaps overlook the problem that archaeology has a checkered past at best when used to support political agendas. (Trigger 1984:615).
Postprocessualism is increasingly popular in America, where processualism originated. To a large extent processualists believe in the scientific method - that archaeology is credible to the extent to which it employs the scientific method, and find the much less scientific nature of postprocessualism to be a step in the wrong direction. In Europe, on the other hand, postprocessualism has become dominant.
Despite differences there is common ground between processualists and postprocessualists. Both processual and postprocessual archaeology want to know about the people of the past. Both are concerned about how we know about people in the past and whether that knowledge represents the actual past or just a personal mental reconstruction of the past. While some postprocessualists argue that any understanding of the past is impossible most believe that, if nothing else, we should still try to do archaeology as best we can while struggling to keep concerns about our own bias constantly in mind. Both wish to eliminate this bias and come to an objective understanding of the reality of the past, however they differ very significantly in how to best achieve this end. Regardless, many archaeologists who tend to subscribe to postprocessual theoretical frameworks rely on many techniques--such as stratified sampling, statistics, and biochemical/material analysis--that originated from a processual mindset.