SPEAKER: Argument
analysis would be a lot easier if people
gave their arguments in standard form, with premises
and conclusions flagged in an obvious way. But people don't usually talk
this way or write this way. Sometimes the conclusion
of an argument is obvious, but sometimes it's not. Sometimes the conclusion
is buried or implicit, and we have to reconstruct the
argument based on what's given. Well, it's not always
obvious how to do this. In this week's
tutorial, we're going to look at some principles that
will help us identify premises and conclusions and
put natural language arguments in standard form. This is a very important
critical thinking skill in general,
but it's also one that is required to answer
many questions on the LSAT. Here's an argument-- abortion is
wrong because all human life is sacred. Question-- which is the
conclusion, abortion is wrong or all human life is sacred? For most of us, the
answer is clear. Abortion is wrong
is the conclusion, and all human life is
sacred is the premise. How do we know this? Well, two things are going on. First, we are consciously
intentionally reading for the argument,
and when we do this, we're asking
ourselves what claim are we being asked
to believe or accept, what other claims are being
offered as reasons to accept that claim? Second, we recognize the logical
significance of that word "because." Because is what we
call an indicator word, a word that indicates the
logical relationship of claims that come before or after it. In this case, it indicates
that the claim following it is being offered as a reason
to accept the claim before it. So, rewriting this
argument in standard form it looks like this. All human life is sacred. Therefore, abortion is wrong. At this point, we could start
talking about whether this is a good argument or not. That's not really the
point of this tutorial. Right now, we're more concerned
with identifying premises and conclusions and getting
the logical structure of an argument right. Here are some key
words or phrases that indicate a
conclusion-- therefore, so, hence, thus, it
follows that, as a result, consequently, and, of
course, there are others. They argument on the right
gives an example using so. It's flu season and
you work with kids, so you should get a flu shot. Now keywords like this
make it much easier to identify conclusions,
but not all arguments have keywords that flag it. Some arguments have no
indicator words of any kind. In these cases, you have
to rely on your ability to analyze context and
read for the argument. Here's a more complex argument
that illustrates this point. We must reduce the
amount of money we spend on space exploration. Right now, the
enemy is launching a massive military
build-up, and when we need the additional money
to purchase military equipment to match the anticipated
increase in the enemy's strength. Notice that there are no
indicator words that might help us flag the conclusion. So which claim is the
conclusion of this argument? Is it we must reduce
the amount of money we spend on space exploration? Is it the enemy is launching
a massive military build-up? Or is it we need
the additional money to purchase military
equipment to match the anticipated increase
in the enemy's strength? You can pause the
video now if you want a second to think about this. OK, the answer is one, we must
reduce the amount of money we spend on space exploration. Most people can see
this just by looking at the argument
for a few seconds. From experience, I
know that some people have a much harder time
seeing logical relationships like this. If it's not obvious to you,
the way to work the problem is this. For each claim asserted
in the argument, you have to ask
yourself, is this is the main point that the
arguer is trying to convey, or is this a claim that's
being offered as a reason to believe another claim? If it's being
offered as a reason to believe another claim, then
it's functioning as a premise. If it's expressing the
main point of the argument, or the argument is trying
to persuade you to accept, then it's the conclusion. Now there are words and phrases
that indicate premises, too. Here are a few-- since, if,
because, from which it follows, for these reasons,
and, of course, there are others as well. Here's an example on the
right they uses since. John will probably
receive the next promotion since he's been
here the longest. Since is used to indicate that
John's being here the longest is the reason for thinking
that he'll probably receive the next promotion. So, let's summarize. Arguments in natural
language usually are presented in
standard form, so we need to know how to extract
the logical structure from the language that's given. To do this, we look at each
of the claims of the argument, and we ask ourselves,
is this the main point that the arguer is
trying to convey, or is this being
offered as reason to accept some other claim? A claim that expresses the
main point is the conclusion. The claims that are
functioning as reasons to accept the main
point are the premises. And finally, premises
and conclusions are often flagged by the
presence of an indicator word, and paying attention
to indicate words can really help to simplify
the task of reconstructing an argument.
