SPEAKER 1: Since arguments are at the heart of logic
and argumentation, it's natural to start with this question.
The first thing to say about arguments
is that as this term is used in logic,
it isn't intended to imply anything
like an emotional confrontation.
Like when I say that an argument broke out at a bar,
or I just had a huge argument with my parents
about my grades or something.
In logic, an argument is a technical term.
It doesn't carry any connotation about conflict
or confrontation.
So here's our definition.
It'll have the three parts.
First part, an argument is a set of claims or statements.
We'll have more to say about what a claim or statement is
later, but for now, it's enough to say
that a claim is the sort of thing that
can be true or false.
Next part, one of the claims is singled out
for special attention.
We call it a conclusion.
The remaining claims are called premises.
And finally, the premises are interpreted as offering reasons
to believe or accept the conclusion.
That's it.
That's the definition of an argument.
Now let's have a look at one.
All musicians can read music.
John is a musician.
Therefore, John can read music.
These are the premises, and this is the conclusion.
Premises one and two are being offered as reason
to accept the conclusion that John can read music.
This may not be a particularly good argument, actually,
since that first premise makes a pretty broad generalization
about all musicians that isn't very plausible, I don't think.
I'm sure there are a few great musicians out there that
don't read sheet music, but it's an argument nonetheless.
Now, notice how it's been written.
The premises are each numbered and put on separate lines,
and the conclusion is placed at the bottom
and set off from the rest by a line and flagged with the word
therefore.
This is called putting an argument in standard form,
and it could be useful when you're doing argument analysis.
In ordinary language, we almost never are this formal,
but when you're trying to analyze arguments, when you're
investigating your logical properties,
or considering whether the premises are true or not,
putting an argument in standard form
can make life a lot easier.
And just to highlight this point,
here's another way of saying the same thing.
Can John read music?
Of course.
He's a musician, isn't he?
These actually express the very same argument,
but notice how much easier it is to see
the structure of the argument when
it's written in standard form.
In the second version in yellow here, you
have to infer the conclusion John can read music
from the opening question and the of course part,
and you have to fill in an assumed premise.
What you're given is Jon is a musician,
but the conclusion only follows.
If you assume that all musicians, or most musicians,
can read music, which is not given.
It's just a background assumption.
The argument only makes sense because you're
filling in the background premise automatically,
but you can imagine that this might become
a problem for more complex arguments
where you can't always be sure that everyone is filling
in the same background premise.
So the standard form can be helpful,
and we're going to be using it a lot in this course.
Here are the takeaway points to remember from this.
First, an argument is just a set of claims
that are offered as reasons to believe or accept
another claim.
Second, we saw that the same argument can
be written in more than one way, and in general it's
true that the same argument can be written or expressed
in many different ways using different words,
different sentences, and different sentence structure.
Now, because of this, it is often
helpful to put arguments in standard form
where you can clearly identify which parts of the argument
are functioning as the premises and which
part is the conclusion.
And you make all the premises and background assumptions
explicit by writing them on separate lines.
Being able to do this is actually
an important skill in logic.