We've looked at some examples of unjustified ad hominem arguments, and
we've looked at some examples of unjustified appeals to authority.
Now, all of those arguments, the unjustified ones, are examples of
fallacies of relevance. And because they're fallacies, they're
bad arguments. Now, remember I said, at the beginning of
the lecture on fallacies of relevance, that a fallacy of relevance could still
have some other good qualities of an argument.
So, for instance a fallacy of relevance could be valid.
It could be an argument where there is no possible way for the conclusion to be
false if the premise is true. Now I'd like to give you an example of a
fallacy of relevance that is nonetheless valid.
Consider something very strange that I just saw the other day.
Speaker: You know why I'm so nervous? Because I've got a nervous system, I
assure you I have a nervous system. Speaker: Now suppose, after seeing what I
just saw, I made the following argument, which is an appeal to authority.
I say. Walter offered his assurance that he has
a nervous system. And from that premise I draw the
conclusion that Walter has a nervous system.
That looks like an appeal to authority. He offered his assurance that he has a
nervous system So you must have a nervous system, right? Well if that argument is
an appeal to authority, it's unjustified. And the reason why it's unjustified is
that even thought Walter thinks that he has a nervous system, his merely thinking
it Doesn't gaurantee that he's right, does it? Trick question.
Trick question. Because nothing, in fact, can offer it's
assurance that it has a nervous system, unless it really does have a nervous
system. Consider, for instance, Walter's
mechanical toy parrot, Sebastian. Whenever Sebastian hears Walter say
something at a certain volume, Sebastian repeats back whatever it is that Walter
said. So, when Walter says, I have a nervous
system, in Sebastian's presence, Sebastian repeats back I have a nervous
system. Now even though Sebastian repeats back, I
have a nervous system. Sebastian isn't offering its assurance
that it has a nervous system. It's just a mechanical toy parrot.
So it's making sounds to the effect that, it has a nervous system, but it's not
offering its assurance, about anything. A mechanical toy parrot doesn't have any
assurance to offer. It's also true, that a mechanical toy
parrot, doesn't have a nervous system. So, this argument here, while it might be
valid, is nonetheless, i fallacy of relevance.
It's an unjustified appeal to authority. Nonetheless, perhaps unbeknownst to the
person who makes the argument, it is valid.
There is no possible way for the premise to be true if the conclusion is false.
Now I realize this may be hard to believe,
but recently, over recent generations that is, pigs have been evolving to
acquire opposable thumbs. And given the general level of porcine
intelligence, this could mean a complete reshaping of the planet.
Speaker: Trust me, I am not lying about this.
This is for real. Speaker: Hmm.
Well, Ron said he wasn't lying. So I guess pigs are developing opposable
thumbs. Speaker: Now the reasoning that you just
saw Anthony do might have looked simple, but actually it involved 2 steps. Let's
analyze those steps. First, he heard me say that I was not
lying when I said that pigs are evolving opposable thumbs.
So from the premise that I said I was not lying,
when I said pigs were evolving oposable thumbs, Anthony concluded that indeed I
was not lying when I said pigs are evolving oposable thumbs.
I noticed that first step in reasoning is an appeal to authority.
Anthony is appealing to my authority, when I said that I was not lying, because
I said I was not lying, Anthony concludes that I was not lying.
But now consider the second step of his reasoning.
From the premise that I was not lying when I said pigs are evolving opposable
thumbs, Anthony drew the conclusion that pigs really are evolving opposable
thumbs. But that, is another appeal to authority.
From the fact that I was not lying when I said pigs are evolving opposable thumbs
all that follows is that I really believe that pigs are evolving opposable thumbs.
It doesn't yet follow that pigs really are evolving opposable thumbs.
Am I someone who knows what I'm talking about when I talk about porcine
evolution? If not, then this second step in reasoning is not justified, it's an
unjustified appeal to authority. Simply because I believe that pigs are
evolving oposable thumbs doesn't mean that they really are.
So in the apparently simple reasoning that we just saw Anthony perform, there
were really 2 steps, and each one of those steps was itself an unjustified
appeal to authority. See, appeals to authority can be very
tricky. They can go past without our even
noticing.