Tony Proctor has a thoughtful post over at Parallax View, discussing the concept of "proof" and how it differs in science and in genealogy. I encourage you to read the whole thing as he has a lot to say. Since thoughtful theoretical discussions are scarce in genealogy, I thought I'd add three thoughts.
(1) I'm surprised that neither the post nor the comments allude to the Genealogical Proof Standard (GPS) or the recent book that explains it most thoroughly, Thomas W. Jones's Mastering Genealogical Proof.
FYI if you're new: the GPS is the only widely accepted standard of proof in genealogy, and it states that no conclusion is proved without five things: thorough research, good citations, analysis and correlation of evidence, resolving any contradictions, and a written account. The best genealogists then working put this GPS together at the end of the 20th century under the auspices of the Board for the Certification of Genealogists (BCG_, as an improvement for our purposes on the "preponderance of the evidence" standard borrowed from the law.
(2) Tony writes,
"Science is about the here-and-now whereas genealogy is about the been-and-gone. What this means is that genealogy only has a finite set of evidence available, and although more of that set may be discovered over time, no evidence outside of that set will ever be found. It also means that evidence cannot be created on demand in order to solve a particular problem, or to support/refute a given proposition. On the other hand, in science — technology permitting — an experiment can be conceived purposely to test a given theory, or to separate two competing theories. . . . Whereas science can usually conduct a specific experiment to disprove some of the candidate theories, and so support the remainder, genealogy can only search for more items of evidence that already exist. If they don’t exist somewhere now then they never will in the future either."Some sciences, such as paleontology, are about the been-and-gone. I suppose that in the abstract both genealogy and paleontology only have "a finite set of evidence available," but in practice nobody knows all of it or even where it is. Both paleontologists and genealogists find new evidence all the time.
It's true that paleontologists and genealogists cannot conduct laboratory experiments on the past. But they do have the ability to make predictions based on what they know, and then see whether further research supports those predictions. These predictions and tests are quite similar to an experiment. If I find that a man's wife is named in a deed where he sells property, I can predict that there is likely to be some additional evidence of the marriage that I have not yet seen (whether a formal record of the event or an appearance in an obituary), and go look for it.
But I have a quarrel with the whole idea of a "finite" amount of evidence anyway. Evidence is information that can be used to answer a specific question. (That is the agreed genealogical definition.) Sometimes ingenious genealogists find evidence where others might not have perceived any at all.
In a recent NGSQ article by Judy G. Russell, she used records of people working on roads to ascertain when someone died (who had never worked on the roads). Many genealogists would not have thought of using that information as evidence to answer the question "When did Mrs. X die?"
I'm inclined to think that even if the amount of genealogical information is finite, the amount of evidence is not, because it depends on human ingenuity in the use of the information -- much as scientists use ingenuity to design experiments. (Improved indexes can also make information much more available to be used as evidence, as in this example from a few days ago.)
(3) IMO, it's useful to figure out just what constitutes "proof" or "evidence" in different disciplines. I don't think it's useful to fuss about whether one discipline can use the word in a different sense than another discipline, because that's just not going to change. It's not that hard to understand that new evidence can supersede a past proof in genealogy as in science, and that that kind of thing does not happen in mathematics.
(Happy New Year! By Blogger's count, this is MWM blog post #1300.)
Judy G. Russell, “'Don't Stop There!,” National Genealogical Society Quarterly 99(1):37, March 2011.
Harold Henderson, "Is there a finite amount of genealogical evidence?," Midwestern Microhistory: A Genealogy Blog, posted 1 January 2014 (http://midwesternmicrohistory.blogspot.com : viewed [date]). [Please feel free to link to the specific post if you prefer.]