Evidence
I have a problem with 'evidence' when people state that the absence of evidence means that a thing does not exist.
The problem is thus:
Evidence is only as good as the means of detecting it at that time.
question:
Does a thing recently shown to exist only exist after the evidence is found ?
Does evidence bring a thing into being?
NO and NO
Does the thing for which evidence is required exist before and in the absence of that evidence.
yes and no - depends what it is.
Evidence does not bring a thing into existance but the absence does NOT mean a thing exists until proven to not exist.
Thus altogether relying on evidence or 'lack thereof as a means of defining whether a thing exists or not is fallacious.
EDIT: I made a VERY significant typo when I wrote this ! Please read again in context intended.