What is a fact? Google the definition of fact and you'll get a variety of answers. Most definitions hinge on the concept of truth. So a common definition would be that a fact is something that can be proved true.

Then how do you define truth? Well, one definition asserts that truth is a fact that has been verified. We're back where we started.

John Keats, the great poet, had a different slant on truth. He wrote that "beauty is truth, truth beauty." Mull that one over.

Mark Twain weighed in by stating that "facts, or what a man believes to be facts, are always delightful. Get your facts first, and then you can distort 'em as much as you please."

Genealogists frequently wrangle with these concepts of facts and truth. We try to figure out what is true, or factual, about our ancestral past and what is Pulitzer Prize-worthy fiction.

Pulling together an accurate family history is problematic because we rely largely on the efforts made by humans decades, even centuries, ago. And humans, as we all know, are prone to blunders, miscalculations, carelessness and gargantuan goofs.

That's why every time we collect a piece of information about our ancestors from a source, we need to always consider the reliability of the source.

In the genealogy world there are two kinds of sources: original and derivative. An original source is something created by someone with firsthand information about the details of an event. A derivative source is basically anything that provides information apart from its original form.

For example, an original death certificate filled out by a physician who was present at the time the dearly deceased departed would be considered an original source.

That original death certificate may have been sent to the state or county for safekeeping. And, maybe the county recorder transcribed all of the information from the death certificate into a ledger book. The details in the ledger book would be considered a derivative source, even if the careful clerk accurately recorded everything from the original source.

And that's the kicker. Just how careful were the recorders and transcribers of our ancestral comings and goings?

Maybe that physician had spent the last 30 hours helping to deliver a stubborn baby and when he arrived at Granddad's deathbed he wasn't quite sure what time it was or what day it was.

In his sleep-deprived stupor, he might have mistakenly written that Granddad expired on the 21st when it was actually the morning of the 22nd. So even though we have an original source, the information may not always be true, factual or reliable.

Also keep in mind that sources often contain two kinds of information: primary and secondary. Primary information comes from an actual participant or observer of an event. Secondary information is based on what people believe or claim to be true even though they don't have firsthand knowledge of the event.

Since the good doctor was present at the death, the date and time of death and the identity of the deceased would be considered primary information.

However, death certificates often include place of birth and birth date. Since the widow who provided those details to the doctor probably wasn't present at her future husband's birth, that information would be classified as secondary.

You can see how easy it is for errors to creep into both original and derivative sources. That's why cautious genealogists are bona fide skeptics.

Just as Twain said, facts can be distorted and genealogical realities can be far from the truth.