The Art of Tetman Callis

“Any hypothesis that is incapable of being tested is an invalid hypothesis. A hypothesis developed based on the absence of data is an example of a hypothesis that is incapable of being tested. The inability to refute a hypothesis does not mean that the hypothesis is true.” – Technical Committee on Fire Investigations, Sec. 4.3.6.1, NFPA 921 Guide for Fire and Explosion Investigations (2011 Edition)