Fragments of a Theory of Human Plausible Reasoning 
 
 The paper outlines a computational theory of human plausible reasoning constructed from analysis of people's answers to everyday questions. Like logic , the theory is expressed in a content-independent formalism . Unlike logic , the theory specifies how different information in memory affects the certainty of the conclusions drawn. The theory consists of a dimensionalized space of different inference types and their certainty conditions , including a variety of meta-inference types where the inference depends on the person's knowledge about his own knowledge. The protocols from people's answers to questions are analyzed in terms of the different inference types . The paper also discusses how memory is structured in multiple ways to support the different inference types , and how the information found in memory determines which inference types are triggered.  