Dual-process models share a subset of beliefs about the quest for knowledge, opinions, and understanding. Each section of this chapter explores a theme that is common to these models, and traces some of the historical roots of the assumptions made concerning human epistemology. Four themes are explored: the construction of knowledge; producing meaning and closure through removing doubt; preparing for action and experiencing control; and the notion of limited capacity and the least-effort principle. The authors discuss the counterintuitive notion that intent, will, and control can operate without awareness. Dual-process models are not inconsistent with this idea of preconscious control. Rather, the models have simply evolved following a set of principles that have shifted away from this notion. But there is nothing inherent in the principles underlying these models that rules out the possibility of such control. Examining the interaction of active and passive processes is a fruitful direction for future research; and, despite the placement of such processing strategies at opposing endpoints of a metaphorical continuum in most dual-process models, there is no reason to assume that heuristic and systematic processing cannot operate concurrently.