Re: Genealogy For The Beginner

Haines Brown <brownh@[EMAIL PROTECTED]
> wrote:
>Bob has touched upon some classic philosophical issues. Perhaps by
>exploring them a bit we can arrive at a better grasp of the significance
>of data and their interpretation.
>
>The first thing that needs to be done is to be clear about the
>difference between data and facts.
>...

I find nothing in your summary objectionable.  But you omitted one
concept I don't fully understand myself in its technical aspects, but
still use metaphorically when thinking about data and facts.  

That concept is the one of "fuzzy" truth values (and thereby fuzzy
logic).  Very seldom can we assign perfect truth or perfect falsehood
to an alleged fact, and sometimes we aren't all that sure what
standard of truth we want to apply to a putative fact.  

Hugh has three possible ancestors to his earliest "proven" ancestor.
He could, by whatever means he chose, assign a fuzzy truth value to
each of them, thereby entertaining all three possibilities at once.
If he ever gets further information, the truth values he assigns might
change.

In computer terms, since this is a computing newsgroup ...

One of the problems with data display in modern genealogy programs is
that there is usually no way to communicate fuzzy truth.  In Legacy, I
can assign a confidence level to a source for a particular datum, but
unless someone digs down into the innards of my data and looks at that
confidence level, they'll never see it - it doesn't figure into any of
the displays or re****ts above the obscure footnote level that in fact
probably nobody will ever read, including me.  So I never bother
filling it in.

If I had 3 different possible ancestors, and could assign weights of
probable truth to them, I'd kinda like to see some sort of
probability-tree display, so that when I show the pedigree of X, I can
somehow see the range of possibilities, the confidence level, and of
course which choice is currently the most likely.  I envision a tree
display that would display the most likely choice, but perhaps if you
hovered on a particular link, it might display multiple trees
overlayed, with different colors or densities based on relative
likelihoods. 

I could imagine that with proper calculation that I don't myself know
how to do, that immediate ancestors that one is sure of, would show up
dark and boldly colored, and as one works back up the tree towards
Adam and Eve, the lower probabilities of the data being factual would
show up less bold and dimmer.  The lines one has more evidence for
would be strong, and the lines with weaker evidence or multiple
possibilities would show up weak (and expand into the multiple options
being displayed in the appropriate user-interface conditions).

But I haven't thought this through, much less spec'd it out enough
that I could expect someone to write software for it.  But in all the
debates on this forum regarding data models, when we have numerous
definitions of the relation "father" as well as the inherent
uncertainty of the data which assigns a particular label "father" to a
relation, being able to re****t and display multiple options
graphically or hypertextually (or whatever other newfangled means
someone might come up with) would seem to be an aspect of the problem
worth consideration.  After all, the data model should take into
consideration the forms of input and output that are needed.

I've probably rambled too long, on only a couple hours sleep, so I'll
stop here and let you or other shoot me down. %^)

lojbab