Fascinating as this is, the fact remains that I had not put my ancestor's parentage on my tree because I have not yet satisfied myself as to which, if any, is correct. Certainly one of the allocated sets of parents is definitely wrong as their son died as an infant.
Genealogy as "best fit"
Genealogy is usually a matter of "best fit". As you get further back in time corroborating sources may not have survived even if they existed in the first place. The world of Internet Genealogy, morever, lulls the researcher into thinking that the result pulled up by the search engine or hint is correct. The absence of detailed information about its source - its gaps, limitations, scope and purpose - on many genealogical sites compounds this, particularly without benefit of local knowledge on the part of the researcher.
"The truth is out there" - original records
There are many original records out there in archives and record offices which could possibly give the lie to your careful genealogical conclusions. As a professional researcher my fear is always that I have missed that obscure but vital record in my otherwise thorough search. Many times when researching for clients I have found that their original assumptions although carefully researched were incorrect - sometimes the proof of an ancestor's lineage consists of proving that they are not someone else! Looking at the "small print" of a person's life - taxation returns, rate books, parish relief, tithe apportionment - and basic common sense - a mother does not usually give birth twice in 6 months in 2 different places a long way apart - are some of the keys to demolishing brick walls.
Genealogy "do-over" - find new sources
The genealogy "do-over" is in part a recognition of this fact. What seemed a logical assumption in the early days of your research may now be disproved in the light of greater experience and knowledge of other sources. More records being digitised and put online are giving all of us access to a vast variety of sources but there is still so much more out there - on microfilm and as manuscripts in archives, record offices, university special collections, libraries and even on ebay.
Don't rely on the Internet as it is only the tip of the iceberg. I spend my working life researching in archives finding new and interesting sources of information for clients. I am constantly amazed by what is out there in vaults somewhere, sometimes only accessed via manuscript catalogues.
Some records have not survived
Equally I am frustrated by what has not survived. When I think about