Three "revolutions" in California archaeology have affected methods. The first rejected early stage concepts, such as paleolithic and neolithic, in favor of the empirical concept that it was the assemblage itself that made up the archaeological culture. The second rejected the empirical in favor of an abstract view that identified archaeological materials as residues of cultural behavior. A major marker of this approach was an emphasis on variability. The third was forced upon the discipline through the advent of legally mandated archaeology which brought radical transformations, though with little intellectual guidance. The emergence of a significant regional archaeology is one effect of this revolution. Each revolution created a problem-solving environment that stimulated rethinking of appropriate methods.