Today, we're going to talk about fallacies, of relevance.
Lets start, by talking about ad hominem arguments.
Ad hominem means to the person. An ad hominem argument is an argument
that starts with premises about a particular person, a person who is
engaged in making some point or defending some claim.
And then, it draws a conclusion from those premesis against the point that the
person was making, the conclusion that they were attempting to defend.
So, I can try to make this idea clearer by giving three kinds of examples of ad
hominem arguments. The three kind of examples that I'm going
to be talking about today are deniers, silencers, and dismissers.
Let's consider an example from each kind.
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So, a denier ad hominem argument is an
argument that begins with premises about a person who is making a certain point or
defending a certain claim and concludes that a point that they were making or a
claim that they were defending is false. Let me give you an example of a denier ad
hominem argument. Suppose that Lucy has been accused of
murder. And her alibi is that, at the time the murder was committed, she was
with Louie. Now, Louie gets up and testifies that he
was with Lucy at the time the murder was committed and she was nowhere near the
scene of the murder. But now, suppose we find out that Louie
has a history of perjuring himself on the stand.
He's paid to purger himself. He's a very good perjurer because he can
pass lie detector tests with flying colors even when he's lying.
And he doesn't exhibit any of the behavioral signs of lying that's
detectable by the police or any other courtroom expert.
So, Louis makes a living as a hired perjurer.
That's something we find out about Louie. Now, if we find this out about Louie,
that could lead us to conclude that what Louie said on the stand was false.
He was purjuring himself, as he normally does.
So, here we have an ad hominem argument. We start with premises about Louie, that
he's a hired perjurer, that he perjures himself regularly in the courtroom when
he's on the stand. And, we draw a conclusion about the truth
of what it was that Louie said on this occasion, namely that it's false that he
was with Lucy at the time of the murder was committed.
That's an example of a denier ad hominem argument.
Now notice, the particular argument I just gave seems like a pretty good
argument. In fact, this is a case of an ad hominem
argument that is not fallacious. It doesn't commit a fallacy of relevance.
If, in fact, we do find out that Louie is a hired perjurer, that he's a career
perjurer, then we should conclude that what he's saying on the stand, in this
instance, is false. That's at least pretty good evidence that
it's false. So, this is a case where we have an ad
hominem argument that's not guilty of a fallacy of relevance.
But consider another case where we have an ad hominem argument that's a denier
but that is guilty of a fallacy of relevance.
Suppose that Louie is not a career purgerer at all.
Louie gets on the stand and testifies that he was with Lucy at the time that
the murder was committed. But, Louie is dressed in really, really
shabby clothing that he probably bought in the 1970s.
Under these circumstances, we might conclude that what he's saying is false.
But why would we conclude that? Well, we might say,
look, the guy dresses in really shabby clothing that he bought in the 1970s.
He's got to be lying. Now, that's an ad hominem argument also.
It starts with premises about the person who is testifying, in this case Louie,
and it draws a conclusion about the truth of his testimony.
In this case, that what he was saying was false.
But that ad hominem argument, though it is a denier like the first ad hominem
argument that we considered, is a fallacious argument.
It's not a good argument at all. Just because Louie is dressed in shabby
clothing that he bought in the 1970s, that has no tendency whatsoever to show
that what he's saying was false. So, deniers are a kind of ad hominem
argument. But, some of them commit the fallacy of
relevance and some of them do not. Now, let's consider another kind of ad
hominem argument. The second kind of ad hominem argument
I'm going to call a silencer. [SOUND] The second kind of ad hominem
argument that I want to discuss is the kind of argument that we're going to call
a silencer. A silencer is an argument that starts
from premises about a person who is trying to make a point or defend a
conclusion, and that person's entitlement to make that point or defend that
conclusion in the situation which they were doing so.
It starts from premises about that and moves to a conclusion about the point
that they were making, or the conclusion that they were defending.
So, let me give you an example. Suppose that while Lucy is on trial for
murder, and witnesses are being called to the stand, lawyers are questioning them
and cross examining them. All of a sudden, Charlie runs into the
courtroom, breaks open the door and yells at the top of his lungs, I saw Lucy kill
the victim. Okay.
Now, Charlie might say that. But in that situation, in the middle of a
courtroom, that is not something that we can take into account in determining
whether Lucy is innocent or guilty. The jury cannot consider Charlie's
testimony, if that's what you want to call it.
That testimony does not count as evidence in a courtroom.
So, we could say Charlie had no right to say what he did in the situation in which
he said it. He was not entitled to speak in that
context. So, his testimony is invalid.
Discard it, don't pay any attention to it.
That's an example of, a silencer argument.
It's an argument that starts from premises, about Charlie's entitlement to
speak in that situation, and moves to a conclusion about whether we should pay
attention to what he was saying. That's an example of a silencer argument.
But that silencer argument is a justified one.
It's not fallacious. Here's an example of a fallacious
silencer argument. Suppose that Charlie is called to the
witness stand and he's examined by one lawyer and cross examined by another
lawyer. And during the course of his testimony,
Charlie testifies that he did see Lucy murder the victim.
He saw with his own eyes. But, as he's testifying,
he speaks in an unusual foreign accent. Now, someone might say, well, Charlie
speaks with an unusual foreign accent, therefore, we should pay no attention to
his testimony. Now, that's also a silencer at hominem
argument. But that's an example of an unjustified
silencer ad hominem argument. Just because Charlie speaks in an unusual
foreign accent, that's no good reason to think that we shouldn't pay attention to
his testimony. So, there's a case of an ad hominem
silencer that does commit a fallacy of relevance.
The third kind of ad hominem argument that I want to talk about is a kind of
argument that we're going to call a dismisser.
[SOUND] A dismisser is an argument that starts from premises about a particular
person who's trying to defend a conclusion or make a point.
And the dismisser argument moves from those premesis to a conclusion that says
that we have no reason to believe the conclusion the person is trying to defend
or the point they are trying to make. The dismisser argument doesn't conclude
that we should not believe what the person is trying to defend or the point
they're trying to make. Rather it concludes that we have no
reason to believe, the conclusion the person is trying to defend, or the point
they're trying to make. Rather it concludes that we have no
reason to believe the conclusion of the person that's trying to defend or the
point they're trying to make. Now, what's an example of the dismisser
argument? Well again, consider the situation where Lucy is on trial for
murder. And now, Linus is called as a witness.
So, lawyers are questioning Linus and Linus says that he saw Lucy kill the
victim with her Acme double-edged knife. And then, Linus throws in, for good
effect, acme, there's no knife like it. Now, as Linus offers this testimony, he
happens also to be wearing his Acme promotional t-shirt, his Acme baseball
cap and carrying a big briefcase that says acme on it.
The cross examining lawyer finds out that Linus is actually a sales representative
for the Acme Double-edged Knife Company. Now, under these circumstances, we might
wonder whether Linus isn't just saying that he saw Lucy kill the victim with her
Acme double-edged knife in order to promote Acme knives as effective knives,
as useful tools. Now, if that's why Linus is offering his
testimony, then, we should think of his testimony as a form of advertising.
Not as something that gives us a reason to believe that Lucy actually did kill
the victim with her Acme double-edged knife.
Linus has an interest In getting us to believe that Lucy killed the victim with
her Acme double-edged knife. But his interest in getting us to believe
that is not just an interest in getting us to believe the truth, it's an interest
in making some money for the company he represents.
So, that leads us to wonder whether Linus's testimony is trustworthy.
So we can say, Linus is a representative for the Acme Double-Edged Knife Company,
therefore, his testimony to the effect that Lucy used an Acme double-edged knife
to murder the victim is not testimony that we should trust.
Because he has a vested interest in offering that testimony.
There's a case of a dismisser ad hominem argument.
But that dismisser argument may be justified.
We could give another example, though, of a dismisser argument that is clearly
unjustified but commits a fallacy of relevance.
An example like that would be the following.
While Linus is saying testifying in the courtroom that Lucy killed the murder
victim with her Acme double-edged knife. Linus actually doesn't work as a sales
representative for the Acme Company not does he have any interest in promoting
Acme double-eded knives. But Linus might look like someone who
used to work for the Acme Double-edged Knife Company.
and because of that resemblance, we might be led to think that Linus is as much of
a salesman for the Acme Double-edged Knife Company as this other person was.
They look like each other, maybe Linus reminds us of him.
And so, we might be led to think, based on the resemblance between Linus and this
Acme double-edged knife salesman, that Linus himself has a vested interest in
promoting Acme double-edged knives, and so would be willing to offer false
testimony in order to have a product placement opportunity for Acme
double-edged knives. Now, that would be an example of a
dismisser ad hominem argument that is fallacious.
It draws a conclusion based not on any good reason for that conclusion,
bu rather, based on some resemblance between Linus and somebody else.
A resemblance which is presumably irrelevant to the truth of what Linus is
saying. And so, our argument would in that case
be fallacious. It would be a fallacy of relevance.