"The "scientific method" is not linear, but it is iterative."

No disagreement.

"Data becomes "evidence" when it goes to either support or refute a hypothesis. Data gets meaning in the context of the fire when evaluated against a hypothesis; otherwise, data is data. For example - "The fire alarm activated at 1 am" is data that, in and of itself, only means that an alarm activated at 1 am. When evaluated against the fact that a fire occurred and the hypothesis "The fire started around 1 am" - the alarm data is now evidence that supports the hypothesis. (If there was no fire, the data may go to support a hypothesis that the alarm system is faulty.)"

DATA is INFORMATION that can be documented and verified. EVIDENCE is DATA that is deemed relevant and reliable in a specific context. So, again, no disagreement.

"Hypotheses do not need to be based on evidence. (Your FINAL hypothesis should be based on evidence that supports the hypothesis - after consideration of data that potentially refutes the hypothesis.) A hypothesis can be any statement related to the incident and will either be supported by data or not. The hypothesis is only a statement against which to evaluate data or to guide further action."

The reliable application of the SM requires evidence, not the lack of evidence. So let's take your application that hypotheses do not require any evidence to be developed or formulated, but your FINAL hypothesis must be able to withstand challenges to the evidence to be refuted (with evidence). So if one can develop or formulate hypotheses based on no evidence, then is there not an infinite number of hypotheses that I can generate that need to be disproved or "eliminated" to arrive at a FINAL hypothesis? Is this not a negative corpus methodology?

If we use "hypothesis" to mean that you are CONSIDERING possible hypotheses (i.e., inductive reasoning to analyze the data) that explain what happened based on your education, knowledge, skill, and experience (then look for data that can be used as evidence to FORMULATE a hypothesis) and we use "valid hypothesis" to mean a hypothesis that was FORMULATED with evidence derived from the incident (i.e., deductive reasoning), then it would seem we are applying the same methodology.

"I don't believe there are "invalid" hypotheses when the hypothesis suggests a known or potential cause or origin of a fire; only those that are either supported or refuted within the context of a particular incident. I can hypothesize that the fire originated in the basement of a structure. I can make that hypothesis before I even arrive on the scene, because, based on my knowledge, training and experience, fires sometimes start in basements. If I arrive at the scene and there is no basement or no evidence of fire origin or causality in the basement, the hypothesis fails and we move on to other hypotheses - it wasn't an "invalid" hypothesis, only an unsupported one and becomes useful (assuming there is a basement) in attempting to falsify the hypothesis that the fire originated on the second floor (as a fire in the basement would, potentially, falsify the second floor origin hypothesis) and in refuting confirmation or expectation bias."

The reliable application of the SM does include a step where one considers hypotheses, based on your education, knowledge, skill, and experience to explain what could have happened. It does not have to be based on evidence at this step of the methodology. The following step involves the FORMULATION of a hypothesis to explain what most reliably happened in this specific incident. The FORMULATION produces a valid hypothesis that is based on specific evidence in this specific incident. The ultimate outcome of the reliable application of the SM is not what could have happened (i.e., product of inductive reasoning), but the most reliable explanation of what did happen based on the available evidence. The reliability comes from the use of evidence within the reliable application of the SM. The use of inductive and deductive reasoning produces a "hypothesis" and a "valid hypothesis" in one iteration of the SM.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
(410) 884-3267 (fax)
www.csefire.com