And even with "absolute proof" such as lists made of the children as they were born, and passed down thru the family, people have made errors on those. Not all "absolute is even absolute" and that is when we do have to arrive at a "truth" we will have to stick too. So many people couldn't write, or spell, and then those that did weren't always perfect either. Deciphering some of the old handwriting is not always easy. But we consider ourselves so grateful for any original records that have been kept in family lines, as well we should.