Popper’s next task is to tackle Plato’s descriptive sociology, which includes historic periodization based on the idea of change as well as the ideal social structure. Treating Plato as a sociologist is necessary to fully understand Plato’s political theories. In fact, Popper believes Plato to be not only the first social scientist, but also the most influential in this field. Popper credits Plato with superb observation skills and factual information, albeit mixed with speculation, such as in his Theory of Forms or Ideas (33-35).

Plato uses this theory to explain his understanding of change. Things in the physical world can never be perfect as they are only imitations of Forms or Ideas. However, the closer they mimic the latter, the more perfect and incorruptible they are. In other words, the process of decay is that of moving away from—or losing—the original Form. Akin to the concept of entropy, Plato believes that as time goes on, things become more corrupt in the physical world. As men descended from gods in Greek mythology, they degenerated into women, whereas animals, such as birds, descended from humans (36-37). Popper qualifies Plato’s perception of change as follows: “[C]hange is evil, and that rest is divine” (37).