Evolution can be seen in all aspects of life, but for each aspect evolution does not occur in the same process. In his article titled “Natural Selection, Scale, and Cultural Evolution,” Dunnell highlights and explains why evolution has had such a small impact on archaeology. Cultural evolution and biological evolution are not the same thing. Biological evolution uses theoretical propositions that explain the mechanisms of biological adaptation and evolution. The laws of cultural evolution “are not theoretical propositions but rather empirical generalizations” (Dunnell, 1996: 25). Cultural evolution does not explain the differences between cultural phenomena that occur. Dunnell's main goal is to effectively formulate ways to integrate evolutionary characteristics and anthropological theory (Dunnell, 1996). Dunnell believed that evolutionary biology was a better method for explaining evolution in cultural anthropology and archeology than cultural evolution. The main problem of biological evolution is the dilemma of altruistic behavior in humans, which is the exact opposite of natural selection. Dunnell states that altruistic behavior is “the last of the selfish principles” (Dunnell 1996: 26). The original solution to the problem of altruistic behavior was thought to be to change the scale on which natural selection operates from that of the individual to that of the group. However, Dunnell gives three reasons why this change usually wouldn't work. First, the individual, and not the group, is the means through which reproductivity occurs. Second, the individual is the medium through which observable characteristics are manifested. Finally, changes at higher levels of rank in society, such as that of the group, are too slow for… middle of paper… a “culture” (Dunnell 1988). After a forty-year absence, the method of cultural evolution was revived in the mid-20th century. At first many rejected the revival of this method, even though they still used some aspects of it, i.e. the stages of development of a culture. The 20th century method of cultural evolution differed from the previous model in some aspects, but the main difference lay in the definition of “progress”. During the nineteenth century, “progress” was broadly defined as “the improvement in or resemblance to modern European culture” (Dunnell, 1988; p. 176-177). During the 20th century, however, the term “progress” took on the definition of “increasing the amount of energy captured by society” (Dunnell, 1988; page 177). This simply means that “less developed” cultures used less energy than “more developed” cultures (Dunnell, 1988).