Chapter 1 provides some background on the shift in emphasis from Universal Grammar (UG) to third factors and gives a description of selected third factors, e.g. the Inclusiveness Condition and the Extension Condition. The main emphasis is on the Labeling Algorithm and the Principle of Determinacy. Generative models focus on the faculty of language as represented in the mind/brain. UG is the “system of principles, conditions, and rules” that all languages share through biological necessity. However, although UG received a lot of attention, recently principles “grounded in physical law” and the general “capacity to acquire knowledge” have been emphasized more. This chapter also introduces two main reasons of language change that are responsible for the linguistic cycle: those caused by economy and those by innovation.