James Tanner on his Genealogy Star blog posts an article Methodology vs. Proof in Genealogy worth noting.
His conclusion is that "Genealogy is methodology and cloaking it in the robe of proof does not accurately reflect the processes."
Saying that all proofs are tentative, as Tanner does in the article, is neither new nor especially helpful. It begs the question How tentative? If genealogy can go no further than present the evidence and say the result is tentative, without indicating how tentative, it makes the whole exercise impotent.
We can do better. Proceeding with conventional professional genealogical methodology may get you to a situation where all the evidence aligns and most would agree the issue in question, perhaps a kinship, is highly likely to be the case. Or perhaps the evidence is somewhat at odds. You have less confidence in the conclusion. There is a need for an agreed terminology to express degree of confidence in the result of applying the methodology. It should be expressed in probabilistic terms.
What's the standard? Helen O'Leary wrote in 1998 (http://www.bcgcertification.org/skillbuilders/learyevidencepf.html ) “Science and the law are in agreement: there is only one way to prove kinships beyond reasonable doubt — DNA testing.” Anything else does not meet that legal standard of proof, and as we know there are lots of legal cases where the beyond reasonable doubt standard was met and the person convicted only to have the verdict overturned by DNA evidence.
Genealogy should acknowledge DNA evidence as the gold standard.
Just came across this related article http://m.huffpost.com/uk/entry/3440006