Wednesday, January 1, 2014

Is there a finite amount of genealogical evidence?

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 ( : viewed [date]). [Please feel free to link to the specific post if you prefer.]


Michael John Neill said...

I'd still say the amount of evidence is finite. It's our analysis of that evidence that potentially could be infinite.

Harold Henderson said...

Heh. I shouldn't argue with a mathematician...

I agree that the number of documents and DNA samples is finite. But evidence is what we find relevant to a specific question. And our ability find relevance can grow and change, so that a document that seemed irrelevant at first might later be seen to contain relevant evidence. My argument that there is an infinite amount of genealogical evidence is basically the same as the argument that there are an infinite number of ideas that people might have.

Geolover said...

I agree with Michael John Neill. Both Tony and Harold are right.

Tony: ". . . 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."

Harold: ". . . a document that seemed irrelevant at first might later be seen to contain relevant evidence."

It is indeed the human brain's evaluation of a datum's applicability and import that brings evidence to bear on a conclusion. Galileo and Einstein were working with the same universe, differently perceived.

It's been a good month for discussion of these matters.

NB: the article Harold referred to was Judy G. Russell's ""Don't Stop There!" Connecting Josias Baker to His Burke County, North Carolina, Parents," National Genealogical Society Quarterly 99 (March 2011): 25-41.

A H Zeller said...

I think you must be able to form hypotheses before you can test them. The number of hypotheses, while not infinite, could consume more time than is rationally available.

Tony Proctor said...

Thanks for the analysis Harold. I wanted to compare-and-contrast 'proof' in genealogy and pure-science (actually 'physics' - my background - and hence the reason I excluded other sciences applied to history such as archaeology), and also mathematics which is a very "pure" form but substantially different. My goal was not to criticise the GPS, nor to suggest how people should conduct genealogical research, but to see how close science and genealogy really are. The way we explain things from evidence are very close, and so supports the precision that we attribute to such research. It's unfortunate that the usage of the term 'proof' is less precise but understanding that difference is still important.

As others have pointed out, the issue of "finite evidence" is probably a misinterpretation of what I wrote. There is only a limited amount out there - whether we know of it or whether it's currently hidden from us. Hence, we may uncover more of that limited evidence but it's an asymptotic process. At some point there will be nothing left to uncover. Information that was never recorded at the time (on paper or in memories) is never going to appear in the future, and evidence that has been totally destroyed is never going to be found.

Tony Proctor said...
This comment has been removed by the author.
Harold Henderson said...

Yes, there might at some very distant point be no more *information* left to uncover. But I see no real limit to the possible *uses* of that information. And that's what evidence is. It's defined as information relevant to answering a particular question.

Just as there is no limit to the number of experiments that physicists might think up to answer a question, I don't see a limit to genealogists' ability to reinterpret and combine information to provide evidence in new ways where it was seen to be relevant before. The distinction between information and evidence is crucial here.

That said, Alan Zeller's point is practical. No one of us is going to live long enough to get it all done even on one family!