Ignorantiam, argumentent ad 93
The positive version of ad ignorantiam asserts that what has not
been disproved must happen. There is, in addition, a negative
form which claims that what has not been proved cannot occur.
Talk of extraterrestrial life-forms is nonsense. We know there are none
because every single attempt to establish their existence has failed
utterly.
(Also true of the Yeti, Bigfoot, the Loch Ness monster and editorial
integrity.)In both versions of the fallacy, the appeal is to ignorance. It is
called upon to supply support for an assertion, even though our
own state of knowledge does not normally bear on the truth or
falsity of that statement. The fallacy consists of the intervention
of irrelevant material, in the shape of our own ignorance, into an
argument which is about something else. It is notoriously difficult
to prove that something exists, especially if it is a shy creature
which hides coyly in the deep of a Scottish loch, on the slopes of
a mountain wilderness, or in the mists of the third planet of 61-
Cygni. You practically have to meet one. Even then, a wealth of
recorded evidence would be required to convince others.
To establish non-existence is even more difficult. You have to
look at the whole universe simultaneously to make sure that your
quarry is not lurking in any part of it. Not surprisingly, this feat is
rarely accomplished, and thus leaves us with boundless spaces
thickly populated with ad ignorantiams and the other products of
our imagination.
Kid, I've flown from one side of the galaxy to the other. I've seen a lot of
strange stuff, but I've never seen anything that could make me believe
there's one all-powerful force controlling everything.Of course there are cases in which our lack of knowledge does
influence our judgement; they occur where we would expect to