It is not about definitions. It is about understanding of "what is science?" and "how is science done?" When you understand the process, this characterization of what a "reasonable degree of scientific certainty" can be inferred.

You can never reach 100% certainty and a subjective determination (made without evidence) has 0% certainty, so you will fall somewhere in between. However, there is no way to determine where you lie between those two bounds. Thus, any determination is an informed guess based on evidence and reliable knowledge, not the lack of evidence. This is the best one can do with science. Thus, it is reasonable.

Science is a compilation of reliable knowledge.

The SM is the reliable methodology used to produce science.

A reliable determination is made when your hypothesis is uniquely consistent with the available evidence.

A tested hypothesis is reliable until it is not. All the evidence in the world cannot "prove" a hypothesis, but one piece of evidence can disprove a hypothesis.

If you reliably apply the SM and you are able to reach a determination that is uniquely consistent with the available evidence, your determination has a reasonable degree of scientific certainty. It is not a subjective determination, which is a violation of the SM. And it is not absolute proof with %100 certainty. It is somewhere in between. Because new evidence can be obtained that disproves the hypothesis, it is a reasonably reliable determination...until it is not.

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)
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