WEBVTT

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SPEAKER 1: Since arguments
are at the heart of logic

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and argumentation, it's natural
to start with this question.

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The first thing to
say about arguments

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is that as this term
is used in logic,

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it isn't intended
to imply anything

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like an emotional confrontation.

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Like when I say that an
argument broke out at a bar,

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or I just had a huge
argument with my parents

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about my grades or something.

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In logic, an argument
is a technical term.

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It doesn't carry any
connotation about conflict

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or confrontation.

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So here's our definition.

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It'll have the three parts.

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First part, an argument is a
set of claims or statements.

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We'll have more to say about
what a claim or statement is

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later, but for now,
it's enough to say

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that a claim is the
sort of thing that

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can be true or false.

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Next part, one of the
claims is singled out

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for special attention.

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We call it a conclusion.

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The remaining claims
are called premises.

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And finally, the premises are
interpreted as offering reasons

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to believe or accept
the conclusion.

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That's it.

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That's the definition
of an argument.

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Now let's have a look at one.

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All musicians can read music.

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John is a musician.

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Therefore, John can read music.

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These are the premises,
and this is the conclusion.

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Premises one and two are
being offered as reason

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to accept the conclusion
that John can read music.

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This may not be a particularly
good argument, actually,

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since that first premise makes
a pretty broad generalization

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about all musicians that isn't
very plausible, I don't think.

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I'm sure there are a few
great musicians out there that

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don't read sheet music, but
it's an argument nonetheless.

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Now, notice how
it's been written.

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The premises are each numbered
and put on separate lines,

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and the conclusion is
placed at the bottom

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and set off from the rest by a
line and flagged with the word

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therefore.

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This is called putting an
argument in standard form,

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and it could be useful when
you're doing argument analysis.

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In ordinary language, we
almost never are this formal,

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but when you're trying to
analyze arguments, when you're

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investigating your
logical properties,

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or considering whether the
premises are true or not,

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putting an argument
in standard form

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can make life a lot easier.

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And just to
highlight this point,

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here's another way of
saying the same thing.

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Can John read music?

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Of course.

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He's a musician, isn't he?

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These actually express
the very same argument,

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but notice how much
easier it is to see

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the structure of
the argument when

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it's written in standard form.

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In the second version
in yellow here, you

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have to infer the conclusion
John can read music

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from the opening question
and the of course part,

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and you have to fill
in an assumed premise.

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What you're given is
Jon is a musician,

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but the conclusion only follows.

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If you assume that all
musicians, or most musicians,

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can read music,
which is not given.

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It's just a
background assumption.

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The argument only makes
sense because you're

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filling in the background
premise automatically,

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but you can imagine
that this might become

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a problem for more
complex arguments

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where you can't always be
sure that everyone is filling

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in the same background premise.

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So the standard
form can be helpful,

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and we're going to be using
it a lot in this course.

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Here are the takeaway points
to remember from this.

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First, an argument is
just a set of claims

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that are offered as reasons
to believe or accept

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another claim.

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Second, we saw that
the same argument can

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be written in more than one
way, and in general it's

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true that the same argument
can be written or expressed

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in many different ways
using different words,

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different sentences, and
different sentence structure.

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Now, because of
this, it is often

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helpful to put arguments
in standard form

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where you can clearly identify
which parts of the argument

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are functioning as
the premises and which

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part is the conclusion.

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And you make all the premises
and background assumptions

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explicit by writing
them on separate lines.

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Being able to do
this is actually

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an important skill in logic.