The theorem behind this line of reasoning is known as modus ponens. An encounter with three blind, tailless mice does not disprove the theorem - only the premise that all mice have tails. Credulists are not always as logical. It is no more logical than to assert that everything with a tail must be a mouse. A vacation job in engineering taught me that a design could be proved just by showing that it worked.
Engineers are always eager to please.
They'll build you a bridge. They'll give you a remote control. They always seem to dance to somebody else's tune. The only way engineers seem to be able to gain recognition is by failing short of success. We have all heard of Babbage, whose analytical engine was never completed.