Welcome back. We've covered stages one
through three of argument reconstruction

namely, close analysis, get down to
basics, and sharpen edges. In this

lecture, we'll cover stage four, which is
organized parts. Cuz it's not enough to

isolate the parts and figure out what they
are. We need to show how the fit together

in a structure so that they work together
to support the conclusion of the argument.

To see how this works, let's start with an
example. Consider this example. That

fertilizer won't help the roses bloom cuz
there is already a lot of nitrogen in the

soil. So, the fertilizer will make the
nitrogen levels too high. Of course, so is

a conclusion marker so one conclusion is
that, the fertilizer will make the

nitrogen levels too high. And then, you
might think that one might have put the

argument into standard form goes like
this. Premise one is that fertilizer won't

make the roses bloom. Premise two is the
nitrogen levels in the soil are already

high. And then, the conclusion is that the
fertilizer will make the nitrogen levels

too high. But that doesn't really make any
sense, if you think about it. How could

the fact that the roses won't bloom be a
reason to believe that the nitrogen levels

are too high? This couldn't be a reason
for that. So, we might just have the wrong

structure. However, there is another
argument marker. This time it's a premise

marker, because. And that indicates that
the claim that there's already a lot of

nitrogen in the soil is a premise. But
what is the conclusion for that premise?

That's supposed to show that the
fertilizer won't make the roses bloom. So,

we've missed that part of the structure if
we put it in standard form, the way we

first thought. The trick here is that
there are really two conclusions. One

conclusion is that the fertilizer won't
help the roses bloom, and another

conclusion is that the fertilizer will
make the nitrogen levels too high. But

each argument's just supposed to have one
conclusion. So, how are we going to put

this into a structure? The solution is
that there are two arguments. One is that

the nitrogen levels in the soil are
already high. Therefore, adding the

fertilizer will make them too high. And
the second argument is that, adding the

fertilizer will make the nitrogen levels
too high, therefore the fertilizer will

not make the roses bloom. Now notice that
one argument really builds on the other

because the conclusion of the first
argument is really a premise in the second

argument. So, we can represent them as two
separate arguments. But we can also put

them together in a chain. So that the
argument says, the nitrogen levels in the

soil are already high. Therefore, adding
fertilizer will make them too high. And

therefore, adding fertilizer will not help
the roses bloom. Now, if we take that

whole structure and we try to represent it
in a diagram, and we represent each

premise with a number, which is the number
that was given in the standard form, then

we can simply have premise one with an
arrow to premise two indicating that

premise one is a reason for premise two.
And then, another arrow going from premise

two to premise three to indicate that two
is a reason for three. In a way, we've got

two premises and two conclusions because
that one kind in the middle, number two,

operates as a conclusion in the first
argument and a premise in the second

argument. But overall, I hope the diagram,
its clear. Well, I want to call this

linear structure. When you have one
premise giving reason for a conclusion

which is then premise for another
conclusion, then they form a line in the

diagram them in the way that I am
proposing. Arguments can have other

structures, too. In particular, sometimes
there's more than one premise associated

with a single conclusion. And this can
happen in two ways. The first, we're going

to call the branching structure, and the
second we're going to call the joint

structure. Here is an example of the
branching structure. I'm not going to go

to the movie with you because I don't like
horror flicks. And besides, I'm too busy.

The word beca use is a premise marker. So
that indicates that the conclusion is

that, I'm not going to go to the movie
with you. And there are two premises. One

is, I don't like horror flicks, and the
other is, I'm too busy. Now, you might

think that, that could just be put in the
old linear structure that we already saw.

But then, the argument's going to look
like this. I don't like horror flicks.

Therefore, I'm too busy. Therefore, I'm
not going to go to the movie. But, wait a

minute. The fact that I don't like horror
flicks doesn't mean I'm too busy. That

doesn't make any sense. Oh, maybe it's the
other way around. I'm too busy. Therefore,

I don't like horror flicks. Therefore, I'm
not going to go to that movie with you.

That doesn't make any sense either. The
fact that I'm too busy isn't why I don't

like horror flicks. The problem is, there
are two premises here but neither one is a

reason for the other, as we saw in the
linear structure. Instead, in this

branching structure, each premise is
operating independently. There's one

argument. I don't like horror flicks,
therefore I'm not going to go to that

movie with you. There's another argument.
I'm too busy, therefore I'm not going to

that movie with you. And each premise by
itself is a sufficient reason not to go to

the movie with you. I mean, just think
about it. If I wasn't too busy, but I

didn't like horror flicks, I wouldn't go
to the movie. But if I liked horror

flicks, but I was too busy, I still would
go to the movie. So, each premise by

itself is enough, and they operate
independently. That's what makes this a

branching structure instead of a linear
structure. Let's diagram it and you'll see

why we call it a branching structure. One
way to diagram it would be to simply draw

an arrow between premise one and the
conclusion two. And then, there's a

separate argument, so you draw another
arrow from one star, another premise, to

conclusion two. And that's okay. But,
notice that it doesn't show you that both

premises are reasons for the same
conclusion. So, to capture t hat aspect of

the structure, that both Premise one and
Premise one Star support the same

conclusion, namely two. It's better to
diagram it so that there's an arrow that

runs independently from both premises to a
single instance of conclusion two, as you

see on the diagram on the screen. And that
should show you why we're calling it a

branching structure cuz it kind of
branches, it looks like the branches of a

tree. Okay. Well, it doesn't really look
like the branches of a tree, but you get

the idea. We're going to call it a
branching structure. Next, we have to

separate this branching structure from
what we're going to call the joint

structure. The difference is that in the
branching structure, the premises provide

independent support for the conclusion.
Whereas, in this joint structure, they

work together and they're not going to
have force independent of each-other. It's

like the joint in your leg, which joins
together the calf with the thigh. And, if

you didn't have both, it wouldn't work
very well. So, we're going to call it a

joint structure. Here's an example. For my
birthday, my wife always gives me either a

sweater or a board game. This box does not
contain a sweater. So, this time she must

have given me a board game. Now, notice
that the argent marker, so, indicates that

the conclusion is, this time she must've
given me a board game. And it's got two

premises. And you might think that they
got a linear structure, and the argument

goes something like this. My wife always
gives me either a sweater or board games.

Therefore, this box does not contain a
sweater. Therefore, this time she gave me

board game. That doesn't make any sense,
right? I mean, the fact that she always

gives me either a sweater or board game is
no reason to believe this box doesn't

contain a sweater. Well, okay. Let's try
it again. Maybe it's a branching

structure. That would mean that the
argument looks like this. My wife always

gives me either a sweater or a board game.
Therefore, this time she gave me a board

game. And, as a separat e argument, this
box does not contain a sweater, therefore

this time she must have given me a board
game. Neither of those arguments makes any

sense so it can't be a branching
structure. Instead, what we have here is

the two premises working together. She
always gives me either a sweater or a

board game. And, the second premise, this
box does not contain a sweater. Those two

premises have to work together. It's only
jointly working together that they can

support the conclusion that, this time she
must have given me a board game. How can

we diagram this joint structure? We can
put a plus sign between premise one and

premise two, then draw a line under them
to show that they work together jointly.

And take a line from that line and draw an
arrow down to the conclusion, just like in

the diagram. And this is what we're going
to call the joint structure. So, we've

seen the linear structure, the branching
structure, and the joint structure. And,

we can combine more than one of these
structures into a single argument. To see

how to do this, let's just do a slight
variation on the previous example. My wife

always gives me either a sweater or a
board game. This is box is not contain a

sweater because it rattles when I shake
it. So, this time she must have given me a

board game. This argument combines a
linear structure with a joint structure.

There are two argument markers. One is a
conclusion marker, so, and that indicates

that the eventual conclusion is that she
must given me a board game this time. But

there's also that new word, because, which
indicates that the fact that it rattles

when I shake means that it's not a
sweater. So, the first stage of the

argument in standard form looks like this.
Premise one, this box rattles when I shake

it. Therefore, conclusion, this box does
not contain a sweater. Stage two says,

this box does not contain a sweater, my
wife always gives me either a sweater or a

board game. So, the conclusion, this time,
she must have given me a board game. And,

of course, the conclusion of that fir st
little argument is identical with the

premise of the second argument, so we can
put them together into a chain. We can

say," this box rattles when I shake it, so
it must not contain a sweater." My wife

always gives me a sweater or a board game,
so this time she must have given me a

board game. That's how we get a linear
structure combined with a joint structure.

And we can use our diagram methods to
diagram this argument the same way we did

before. We simply start with premise one,
the box rattles when I shake it. Draw an

arrow down to its conclusion. Namely, the
box does not contain a sweater. That's

two. An then, we show that those are joint
by adding a plus, premise three. Namely,

my wife always gives me either a sweater
or a board game. Draw a line under them

and an arrow from those two together down
to the eventual conclusion, namely, four

that this time she must have given me a
board game. The fact that the top arrow

goes from premise one to two, but does not
go from premise one to three indicates

that, that premises is a reason for two
but is not a reason for three. So when you

use this method to diagram arguments, you
have to be careful where you draw the

arrows. And draw them only where there
really is a rational connection. That is,

where one claim is being presenting as a
reason for that particular claim that the

arrow is pointing towards. Now, almost all
arguments can be diagrammed using these

three simple structures. That is, the
linear structure, the branching structure,

the joint structure, and some combination
of those three. You can add more premises

because you can always add one plus two
plus three plus four if they're four

premises operating together in a joint
structure. And, you can add extra arrows

if you have a branch with more than two
branches. So, you can cover a lot of

arguments using these kinds of diagrams.
The method can be described in general,

like this. You start by identifying the
premises and the conclusions, and you

number them. So that you can just have
numbers instead of having to write out the

whole sentence on the diagram. Then, when
they work together, you put a plus sign

between them and draw a line under it to
indicate that they're working together.

They're functioning as a group. Then, you
draw an arrow from the claims that are

reasons to the claims that they are
reasons for. And then, you move them

around on the diagram so that they'll form
a line when it's a linear structure and

branches when it's a branching structure.
But, it will be easy to rearrange them so

as to show how all of the different
premises and conclusions work together in

a single argumentative structure. That's
going to be enough to accomplish this

stage of reconstruction. Namely, to
organize the parts and show how they work

together in the overall argument.