In this chapter, the nature of the process that each participant engages in individually in order to contribute to collective reasoning is discussed. The design of technological systems that will best support reasoning in its communal context requires the specification of schemes for representing knowledge and for the inference of new knowledge. Further, it is also necessary to articulate a model for the process that individuals engage in when reasoning in groups. The assertion we make is that the process iteratively includes phases of engagement, individual reasoning, group coalescing, until decision making. Representations, including the classical syllogism, first order logic, default reasoning, deontic reasoning, and argumentation schemes, are surveyed to illustrate their strengths and limitations to represent individual reasoning.