In the last lecture, we talked about paradoxes of vagueness.
Arguments that involve vague expressions that are apparently valid, the argument
is apparently valid, and yet the premises are all apparently true, and the
conclusion is apparently false. So, something is wrong with that
argument. Either the argument contrary to
appearences is not valid or the premises contrary to appearances are not all true
or the conclusion contrary to appearances is not false.
Today, we're not going to be talking about paradoxes of vagueness.
We'll be talking about fallacies of vagueness.
That's to say, bad arguments, arguments that are clearly bad that result from the
use of vague expressions, but with these fallacies, we can explain,
we already know how to explain what's wrong with the argument.
Today, in particular, we'll be looking at three fallacies of vagueness,
these are all different versions of what sometimes called a slippery slope
argument. We're going to talk about conceptual
slippery slope arguments, causal slippery slope arguments, and
fairness slippery slope arguments. These are three arguments, all of them
are bad and all of them result from the careless use of vague expressions.
Let's start by talking about what we'll call a conceptual slippery slope
argument. Now, in order to illustrate a conceptual
slippery slope argument, I've drawn a picture here of my children's playroom.
I'll explain to you what the different things are.
This is my daughter's piano, right there, these are the shelves that their various
toys and books are supposed to be on, and these things, right here are their
various toys and books. Now, suppose I were to walk into this
room one day on a typical day when it looks like this.
I would tell my kids to clean up their room, to make it neat.
Now, my kids are young and compliant as it is right now,
and so, they would do what I tell them, but eventually, they won't be so young,
and they won't be so compliant. And at that point, I can expect that they
will offer the following argument in response to my enjoinder to clean up
their room. They'll say, anyhow if they've studied
some logic, they'll say, dad. Look,
suppose we were to take any one of these toys or books,
this one let's say, and, put it up on that shelf,
would that improve our room? No, our room would still be as uninhabitable
then as it is now. Suppose we were to take another one of
these toys or books, this one let's say,
and put it up on that shelf, would that improve our room? No, our room
would still be as unihabitable as it is now.
And what this shows is that you can't improve a room by simply taking one toy
or book from the floor and putting it where it belongs.
The room remains in a state of uninhabitability,
even if you take one toy or book and put it back where it belongs.
Now, right now, our room is in a state of uninhabitability,
but you can't take it from being in a state of uninhabitability.
You can't make it habitable by putting one toy or book where it belongs.
So, even if we were to follow your instructions by putting one toy or book
onto the shelf, and then putting another toy or book onto the shelf, and then
putting another toy or book onto the shelf, it wouldn't change our room from a
state of unhabitability to a state of habitability.
So dad, following your directions would make no difference to the habitability of
our room. That's what I imagine they'll be saying
to me in a few years. Now, let's consider that argument for a
moment. Premise one, the room is now
uninhabitable. Premise two,
you can't turn an uninhabitable room into a habitable one by picking up one thing.
So the conclusion is picking up, things won't change the habitability of our
room. Now, this argument looks a lot like one
of the paradoxes of vagueness that we considered in the last lecture, but here
is the difference. In this argument, premise two is not as
obviously true as the second premise in the paradoxes of vagueness.
In particular, if you think of habitability or uninhabitability as a
matter of degree, then you can see where premise two goes wrong.
Because, you can't turn a less habitable room into a slightly more habitable room
by picking up one thing. If habitability is a matter of degree,
then, we can see how premise two could be false.
You can't make a somewhat uninhabitable room somewhat more habitable by picking
up one thing. See, when we were using terms that seemed
not to be a matter of degree, like bald for instance,
either someone's bald or they're not bald or heap,
either something is a heap or it's not a heap.
In those cases, it might seem that there is no boundary line where you cross from
being not bald into being bald or no boundary line where you cross from being
not a heap into being a heap. But when we're dealing with something
that's a matter of degree like habitability, then, you can change the
degree of the relevant quantity by doing just one thing,
like picking up one thing off the floor and putting it on the shelf.
So in this case, the argument that they are giving, while valid, is only
superficially sound. It's not really sound because premise two
of that argument is not really true and that's why it's a bad argument.
Not because it's not valid, but because it's not sound.
The second premise is not true because they're taking a matter of degree and
treating it like it's not a matter of degree.
So that's an example of a conceptual slippery slope argument.
A conceptual slippery slope argument is an argument to the effect that a series
of particular actions can't change the quality of the thing that we're concerned
with, but typically, the problem with
conceptual slippery slope arguments is that the second premise that they use,
the premise that has this form is false because it takes something that's a
matter of degree and treats it like it's not a matter of degree,
like it's an either/or. So that's the conceptual slippery slope
argument. Now, let's talk about the other kinds of
slippery slope argument. We just talked about conceptual slippery
slope arguments, and now, I want to turn to what we're going to call causal
slippery slope arguments. A causal slippery slope argument is an
argument concerning the effects of a possible course of action.
Let me give you an example. Suppose I propose introducing a bill into
our state legislature. A bill that would ban people from
carrying military style arms, like say, bazookas or nuclear weapons
onto college campuses. Now, I realize this bill is going to be
received as a radical abrogation of freedom in many parts of the United
States. And I can imagine a legislator saying the
following thing, if you don't allow people to carry
bazookas and nuclear weapons onto college campuses, what's the next thing that's
going to happen? Well, the next thing that's going to happen is that
legislators like you are going to try to take away our freedom to bring AK-47s
onto college campuses and what happens after that? Well, before you know it,
we're not going to be allowed to bring any machine guns onto college campuses.
And before you know it, then, legislators are going to take away all our freedoms
altogether. Okay?
So, wow does this argument go? It goes,
if this happens, namely we pass a bill denying people the right to carry
bazookas or nuclear arms onto college campuses.
If that happens, then some further thing of an even more radical nature will
happen. And the argument is a series of premises,
each one of which has this form. If the course of action that you're
considering takes place, if you do this thing, then, some further
thing of an even more radical nature will happen.
If you pass this bill, prohibiting people from carrying bazookas and nuclear
weapons onto college campuses, then imagine what will happen next.
What will happen next is that some bill will pass prohibiting students from
carrying AK-47s into their classrooms and what happens if a bill is passed
prohibiting students from carrying AK-47s into their classrooms? Well, next thing
you know, no machine guns will be allowed on college campuses.
And if that happens, then next thing you know, we won't have any freedoms at all.
So the conclusion of the argument is a conclusion to the effect that if we
pursue the course of action that you're proposing,
then the eventual end result will be a loss of all of our freedoms.
That's the form that the conclusion takes and the premises all take this form right
here. They all take the form of saying,
if we pursue the course of action that you're considering now,
then some further thing of an even more radical nature will result.
And each premise takes that same form and describes a further thing of an even more
and more and more radical nature untill we get something of an unacceptably
radical nature, like the loss of all of our freedoms.
Now, that's an example of a causal slippery slope argument.
And again, the argument is valid, there's no possible way that the premises could
all be true, while the conclusion is false or in any case, the argument can be
designed so as to be valid. There's no obstacle to such an argument
being valid, but the problem with the argument is typically not that it's
invalid but rather that it's unsound, that one or more of the premises taking
this form is not true. So suppose we do pass a bill that
prohibits students from carrying bazookas or nuclear weapons onto college campuses?
Is that really going to result in a prohibition against carrying AK-47s onto
college campuses? Not necessarily. I have to tell you, I don't see it.
Just because students aren't allowed to carry bazookas and nuclear weapons onto
college campuses doesn't mean that some further thing of an even more radical
nature like prohibiting them from carrying AK-47s onto college campuses
would result from that. I mean, maybe, legislatures would just
stop at prohibiting the use of bazookas and nuclear weapons or even the
possession of bazookas and nuclear weapons on college campuses and they
wouldn't proceed to anything of an even more radical nature.
They would still allow students to carry AK-47s onto college campuses as they
pleased, so long as they were licensed of course.
So, typically, the problem with a causal slippery slope argument is not that it's
invalid but rather that it's unsound because one or more premises of this form
is not true. So far, we've talked about conceptual
slippery slope arguments and causal slippery slope arguments.
Now, I'd like to talk about a third kind of slippery slope argument that we'll
call the fairness slippery slope argument.
We call it the fairness slippery slope argument, because it's a kind of argument
that's typically given in the service of showing that a particular policy is fair
or unfair. Let me give you an example that hits
pretty close to home. See, although I teach at the University
of North Carolina at Chapel Hill, my family and I live in Durham, North
Carolina. The city next door to Chapel Hill.
we live right by Duke University. Now there are many nice things about
living close to Duke University. Unfortunately, it means living in
proximity to a lot of people who attend Duke University and part of the problem
with that has to do with their taste for heavy metal music.
You see, a lot of Duke students love to play their heavy metal music at a very
high volume and this presents us with a predictable challenge.
On the one hand, we like to sleep at night when we can.
On the other hand, we have to consider the rights of our Duke student neighbors,
they like to play their loud heavy metal. They like to play their loud heavy metal
music, we like to sleep. What's a fairer solution? Well, some of
our Duke student neighbors have been inclined to argue as follows.
It's fair to allow neighbors to play their music at 50 decibels, that's a
totally reasonably volume. Right now, I am probably speaking to you
in a volume that's maybe a little over 50 decibels.
Allowing your neighbors to play their music at 50 decibels, that's certainly
fair. There should be no legal restrictions on
playing your music at 50 decibels. Now, adding a single decibel of volume,
could that change the fairness of the arrangement? Could it be fair to allow
your neighbor to play their music at 50 decibels, but not at 51 decibels?
It hardly seem right, I mean, after all, the human ear probably can't even
distinguish 50 decibals from 51 decibals. If I were to play those two volumes to
you, the same sound of both of those two volumes, you probably couldn't tell which
was which because they're so close together.
If you can't discriminate between 50 decibels and 51 decibels, then the
difference between 50 decibals and 51 decibels can't possibly make a difference
to whether it's fair to allow your neighbors to play music at that volume.
But if adding a single decibel doesn't change the fairness of the arrangement,
then it's going to be fair to allow your neighbors to play their music at 51
decibels. And again, if adding a single decibel
doesn't change the fairness of the arrangement, it's going to be fair to
allow your neighbors to play their music at 52 decibels.
And again, if adding a single decibel doesn't change the fairness of the
arrangement, then it's going to be fair to allow your neighbors to play their
music at 53 decibals, and so on. But if that's all true, then it's got to
be fair to play, to allow your neighbors to play their music at 150 decibals,
which is the volume of a loud which is the volume of a loud airplane,
so, that doesn't seem right, and yet, it seems to follow from these two premises.
Once again, we have an apparently valid argument from apparently true premises,
for a conclusion which while it might be approved by many of our Duke student
neighbors, my family and I would regard as false.
So, what should we say about this argument?
Well, again, the thing to say about this argument is that since fair in it's
ordinary usage is a vague expression. What we need to do is give it a precise
definition. [SOUND] A precise definition would make
premise to talse. It would make premise two false, because
if we define the fairness of this situation precisely, if we said there's a
precise decibel level and it's fair to allow your neighbors to play their music
at or below that decibel level but not above that decibel level, if we define
fairness precisely in that way, then, premise two would be false and so
this argument, while valid would be unsound.
So, we need a way to define fairness for this situation precisely, and we have a
way of doing that. It's called the law.
The law can define ordinary concepts, like fairness, in a precise way, or
anyhow, precisely enough so as to falsify premises like this.
According to the law, there is an upper level of noise that people are allowed to
make. Making any more noise than that is unfair
to your neighbors. Less noise is fine.
So, the law is an instrument for making precise some of the vague concepts that
we use in ordinary life, vague concepts like fairness,
and by making those concepts precise in their application to particular
situations, we can avoid bad arguments like the kind that my family and I
frequently find ourselves confronted with by our intelligent Duke student
neighbors. Today we've studied some of the fallacies
of vagueness, the bad arguments that typically result from the use of vague
expressions. These are all slippery slope arguments
and they've come in three forms that we've considered, conceptual slippery
slope arguments, causal slippery slope arguments, and fairness Slippery slope
arguments. In the next lecture, we're going to
consider fallacies that arise from the incautious use of other expressions,
ambiguous expressions, expressions that carry with them more than one meaning.
See you next time.