The newspaper report mentioned in yesterday's post, relating the story of Captain Bell's supposed grant of land, is a typical example of secondary evidence. Appearing in the press about 60 years after Bell's death, it is based on the personal memories of one John Chalsty, who at the time of publication was a very old man.
Information of this sort, created long after the events described, cannot be relied upon. Even contemporary press reports - including such items as lists of passenger arrivals, accounts of shipwrecks, and obituaries - do not fall under the heading of primary evidence. Passenger lists given in newspapers were frequently based on third-hand transcriptions and usually contain inaccuracies. If the ancestor was high-profile enough to merit a published obituary (and many were not) it's likely to give a glowing version of his accomplishments which may make his descendant proud but glosses over any less worthy - and possibly more intriguing - aspects. In short, obituaries seldom 'tell it like it was'.
Family trees - in print or on the web - should be regarded with suspicion, as should published family histories, biographies and autobiographies.
Transcripts of original documents (or of copies of original documents) may include errors, no matter how careful the transcriber.
ANCESTOR & DESCENDANT
On the subject of errors, I find the terms 'ancestor' and 'descendant' are often used incorrectly. An ancestor is the person from whom one descends and strictly-speaking shouldn't be applied to past family members in general. A descendant is a person who has a proven descent from a particular ancestor. This seems obvious, but, for example, much as I'd like to claim relationship with Alexander Graham Bell (and perhaps that might be proved at some future date) I cannot refer to myself as his descendant. Terrick FitzHugh points out that someone could not be described as a descendant of the poet John Keats, who had no children and therefore has no descendants. A person descended from Keats's brother cannot refer to Keats as his ancestor nor to himself as a descendant of Keats.