The relational system of the functions within a single moment of consciousness extends not only to the future but also to the multiplicity of past states of consciousness that are its conditions. That is to say: mental factors, far from being self-contained units, are "open" toward the past as well as the future, and, though meeting in one moment, they are related to quite different "layers" of those time periods. From that we can gauge the highly dynamic nature of the processes going on in a single moment of consciousness. (p. 40)