It is a matter of quasi-consensus among argumentation researchers that enga
ging in argumentation sets the scene for changes in people's views. However
, the actual process by which such changes occur has not yet been entirely
understood. This article represents an effort towards understanding how pro
cesses of knowledge building and transformation evolve in argumentation, To
achieve this goal, it outlines a unit of analysis designed to capture the
process by means of which knowledge is continuously updated through argumen
tation. Then, the analysis of fragments of people's argumentation illustrat
es how this unit of analysis can be utilized. It also provides an account o
f some of the ways in which reasoning is organized in face-to-face argument
ation as well as in the speaker's own discourse. Copyright (C) 2000 S. Karg
er AG. Basel.