I understand there are many people within the fire investigation community that thinks the term “Scientific Certainty” has no place in fire investigations. I will not argue that they have some points to make. Where they have many reasons for their opinion, I have not seen where they have taken the time to define these two words.

It is the view of the National Commission on Forensic Science that the term “Reasonable Degree of Scientific Certainty” because the term has no scientific meaning. Supporting their opinion, they mention different court cases where the disallowed the use of the term. They also say that scientists do not use this term. Based on that, they believe the use of the term will mislead a judge or jury. They say there is no common definition for the term.

Before one criticizes how the words are being used, they need to first learn the meaning of the word. I would how many of those against this term know the definition of each word.

I looked at the Marriam-Webster edition that NFPA requires to be used for their documents.

The word Reasonable is defined as the following when it comes to a theory.

1. Being in accordance with reason.
2. Reason is the sufficient grounds of explanation.

When we use the word “Reasonable” when describing our conclusions what we are saying is that our conclusions are based on sufficient grounds to explain what took place.

Now the word Degree. One of the definitions for that word is to an extent.

All we are saying when the term “To A Degree” is used is that our action is to an extent

As to the word Scientific, the dictionary defines this word as:

1. of, relating to, or exhibiting the methods or principles of science
2. conducted in the manner of science or according to results of investigation by science : practicing or using thorough or systematic methods

What I would like to know is there anyone that thinks that what is being done in fire investigation not exhibiting the methods or principles of science. After all the years of most of these same people arguing that fire investigation is a science. Now they say the term “Scientific” implies that the discipline of fire investigation is not a science. They say they are worried that a judge or jury might believe when the words Reasonable and Scientific are used together, they will believe it means beyond a reasonable doubt. Are they now claiming the word Reasonable should be removed from the term Reasonable Doubt.

The next question is, are we not investigating fires using a systematic method. Is this method not a manner of scientific. If not, why are we calling it the scientific method. Why not take the word Science out of NFPA 921.

As to the word Certainty, one of the definitions is:

1. The quality or state of being certain especially on the basis of evidence.

Here, is not our certainty of being correct in our conclusion based on the evidence. If we are not basing our conclusions on evidence, then what is it being based on?

If one takes the time to define words being used, as they are required by NFPA to be defined, then the term Reasonable Degree of Scientific Certainty does not seem so out of place.

Here is another way of saying the same thing. My conclusion is based to the extent on sufficient grounds of explanation that was reached by using a systemic method based on the evidence.

Jim Mazerat
Forensic Investigations Group