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SPEAKER 1: Since arguments[br]are at the heart of logic

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

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The first thing to[br]say about arguments

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is that as this term[br]is used in logic,

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it isn't intended[br]to imply anything

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like an emotional confrontation.

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

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or I just had a huge[br]argument with my parents

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about my grades or something.

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In logic, an argument[br]is a technical term.

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It doesn't carry any[br]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[br]set of claims or statements.

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

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later, but for now,[br]it's enough to say

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that a claim is the[br]sort of thing that

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can be true or false.

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Next part, one of the[br]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[br]are called premises.

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And finally, the premises are[br]interpreted as offering reasons

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to believe or accept[br]the conclusion.

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That's it.

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That's the definition[br]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,[br]and this is the conclusion.

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Premises one and two are[br]being offered as reason

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to accept the conclusion[br]that John can read music.

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This may not be a particularly[br]good argument, actually,

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since that first premise makes[br]a pretty broad generalization

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

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

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

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Now, notice how[br]it's been written.

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The premises are each numbered[br]and put on separate lines,

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and the conclusion is[br]placed at the bottom

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

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therefore.

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This is called putting an[br]argument in standard form,

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

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In ordinary language, we[br]almost never are this formal,

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but when you're trying to[br]analyze arguments, when you're

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investigating your[br]logical properties,

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or considering whether the[br]premises are true or not,

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putting an argument[br]in standard form

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can make life a lot easier.

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And just to[br]highlight this point,

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here's another way of[br]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[br]the very same argument,

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but notice how much[br]easier it is to see

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the structure of[br]the argument when

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it's written in standard form.

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In the second version[br]in yellow here, you

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have to infer the conclusion[br]John can read music

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from the opening question[br]and the of course part,

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and you have to fill[br]in an assumed premise.

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What you're given is[br]Jon is a musician,

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but the conclusion only follows.

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If you assume that all[br]musicians, or most musicians,

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can read music,[br]which is not given.

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It's just a[br]background assumption.

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The argument only makes[br]sense because you're

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filling in the background[br]premise automatically,

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but you can imagine[br]that this might become

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a problem for more[br]complex arguments

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

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in the same background premise.

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So the standard[br]form can be helpful,

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

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Here are the takeaway points[br]to remember from this.

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First, an argument is[br]just a set of claims

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that are offered as reasons[br]to believe or accept

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another claim.

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Second, we saw that[br]the same argument can

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

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true that the same argument[br]can be written or expressed

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in many different ways[br]using different words,

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different sentences, and[br]different sentence structure.

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Now, because of[br]this, it is often

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helpful to put arguments[br]in standard form

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where you can clearly identify[br]which parts of the argument

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are functioning as[br]the premises and which

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part is the conclusion.

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And you make all the premises[br]and background assumptions

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explicit by writing[br]them on separate lines.

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Being able to do[br]this is actually

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an important skill in logic.