Premise Indicators, Serial and Convergent Premises, Argument Diagrams

HOMEWORK IS AT THE END OF THE LESSON

Overview

Argument indicator words are words commonly found at the beginning of premises and conclusions. Knowing the most common indicator words allows you to quickly distinguish ‘fluff’ from the important parts of arguments as well as to distinguish between premises and conclusions.

Introduction

In Lesson 1 we looked at the main components of arguments (premises and conclusions) and learned a few ways to identify them. In this lesson we’ll continue the same process but add a few more tools. To identify premises and conclusions we can often use indicator words. Indicator words are words that commonly begin a premise or conclusion. When we start reconstructing longer arguments that you might find in articles there will often be ‘fluff’, sentences that aren’t directly important to the argument. Knowing common indicator words allows us to quickly identify the important components of an argument we might find in an article as well as to provide us with one more tool to distinguish premises from conclusions.

List of Common Indicators for Premises:
Since, because, for, as can be deduced from, given that, the reasons are, first, second, assuming that, as shown by.

Common Indicators for Sub-Premises (premises that support other premises):
For instance, for example, E.g.,. Also the same list for premises.

Common Indicators for Conclusions:
Consequentially, so it follows, thus, hence, therefore, implies that, so, and we conclude that.

Conclusions as rhetorical questions. Often arguers will present their conclusion not in the form of a statement but in the form of a rhetorical question. A rhetorical question is one where the arguer already knows the answer (or thinks they do anyway).

Example 1:

Why shouldn’t we go out tonight? There’s 2 for 1 drinks and all our friends will be there.

The arguers conclusion is that we should go out tonight. The reasons given support this conclusion.

Example 2:

First of all, I’m not very good at climbing trees. And second, I don’t have a tail. Do you really expect me to believe humans came from monkeys?

The arguer’s conclusion is that humans didn’t come from monkeys. We can infer this based on the reasons given and the rhetorical question as conclusion.

Extended Arguments, Convergent and Serial Premises

Overview

Most arguments you encounter in articles and books will contain more than 2 or 3 premises. Also, in more complex arguments major premises won’t obviously be true so the arguer will provide sub-premises to support those major premises. Arguments that contain sub-premises are called extended arguments. Premises can relate to the conclusion and to each other in various ways. In this lesson we will look at convergent premises and serial premises. Convergent premises are independent reasons in support of a conclusion. They don’t depend on each other in any way. Serial premises function like sub-arguments: They are reasons given in support of a more basic premise.

Extended Arguments

Up until now we’ve been applying our analytical skills to relatively simple arguments. Now we will begin to apply those skills to extended arguments. What’s an extended argument? Well, I’m glad you asked: An extended argument is one that (a) has a main conclusion supported by premises which themselves are supported by sub-premises and/or (b) has multiple premises that work together to support the conclusion and/or major premise that independently supports the conclusion. In this lesson we’ll look at (a) which are called serial premises and (b) which are called convergent premises.

Convergent Premises

Convergent premises are independent reasons in support of a conclusion. Let’s look at an example:

Scene: Ami comes back from a two-week camping trip
Mom: (a) Ami, you need to take a shower! (b) You stink and (c) it’s not healthy.

The conclusion is “Ami, you need to take a shower.” It looks like the arguer has given us two independent reasons. First, Ami should take a shower because (b) he stinks. Second, because (c) it’s not healthy to go without showering for two weeks when you’ve been sweating every day.

Both (b) and (c) are independent reasons for Ami to shower. Even if (c) were false or never mentioned it would do nothing to undermine (b) as a reason.

When we formalize an argument with convergent premises it doesn’t matter what order we put them in since they function independently of each other.

Formalizing the argument would look like this (reversing P1 and P2 would also be fine):

P1 You stink.
P2 Going without a shower for a long time is unhealthy
C. You should take a shower.

We can illustrate the structure of convergent premises with what’s called an argument diagram. 

Screen Shot 2017-03-10 at 2.58.35 PM

Diagramming arguments is a useful skill in terms of formulating an argument evaluation strategy. If I know that a conclusion is supported by two independent reasons then I know I need to evaluate two individual premises before I assess the strength of the argument. If one premise is weak, the conclusion still might be well-supported by the other independent premise. In order to conclude that a convergent argument is weak, I need to show that both premises poorly support the conclusion. 

Let’s look at one more example:

(a) Everyday Otis Ponens waits for me at the top of the stairs and (b) he keeps me company when I’m stuck at home alone writing > lessons.
(c) Otis Ponens is the best dog ever. And also (d) he (almost) never pees in the house.

The conclusion is (c). Notice that each premise (a), (b), and (d) are independent reasons that support the conclusion. If I didn’t list one, the remaining ones wouldn’t be any less relevant to the conclusion.

If we formalize the argument it should look like this (P1-P3 could be in any order):

P1. Everyday Otis Ponens waits for me at the top of the stairs.
P2. He keeps me company when I’m stuck at home alone writing lessons.
P3. He (almost) never pees in the house.
C. Otis Ponens is the best dog ever.

The diagram for our argument should look like this:

Screen Shot 2017-03-10 at 3.07.57 PM

If I want to undermine the conclusion, I’ll need to show that all three supporting premises are weak. Just showing that one is weak tells me nothing about the strength of the remaining independent reasons to believe the conclusion.

Serial Premises and the “Why Should I Believe That?” Test

Serial premises are when one premise supports another premise in the same way a major premise would support a conclusion. So, when we reconstruct our arguments, the order in which we put them is going to matter. We can also think of the supported major premise as a sub-conclusion. The terminology isn’t that important so long as you understand the relationship. Let’s look at an example of a serial relationship between premises:

Based on the video clip and some background information we can infer the following argument:
(a) Mugatu is a fashion genius. (b)The pianokey necktie, invented by Mugatu, became an important milestone in men’s fashion. (c) For instance, back in the 80s all the cool kids owned piano key neckties.

The conclusion of the argument is (a) Mugatu is a fashion genius. (See Basic Concepts 1 if you’re unsure why). Once we’ve identified the main conclusion we know that whatever remains are premises which means that they should support the main conclusion. Let’s see:

(b) He invented the piano key necktie is a reason to believe that he is a fashion genius only if it was also an important milestone in men’s fashion. But some people might question that the piano key necktie was an important milestone in men’s fashion. Did the piano key necktie become an important milestone in men’s fashion? Most people will want some reason or evidence to believe it’s true. That’s where sub-premises come in. Sub-premises give support to what might be questionable main premises and will answer the questions “why should I believe [insert major premise]?”. So, why should I believe that the piano key necktie became an important milestone in men’s fashion? Well, because (c) back in the 80s all the cool kids owned piano key neckties.

Don’t believe me? Just look at this cool kid from the 80s:

piano%20key%20necktie.jpg

We may or many not think (c) provides adequate support for (b) but that’s beside the point for now. All we care about is figuring out the relationship between the premises to each other and to the conclusion. In this case, (c) is a sub-premise of the conclusion: it provides support for a major premise (b) but not for the conclusion directly. Premises that directly support the conclusion are called major premises.

Now that we’re familiar with the terminology, let’s put the argument into standard form.

It should look like this:

P1. In the 80s, all the cool kids owned piano key neckties.
P2. The pianokey necktie, invented by Mugatu, became an important milestone in men’s fashion.
C. Mugatu is a fashion genius.

Let’s take a look at the diagram for the argument then I’ll explain it.

Screen Shot 2017-03-10 at 3.35.36 PM

P2 gives us a reason to believe the conclusion and P1 gives us a reason to believe P2 and so it (P1) is the sub-premise or P2. 

In some arguments it will sometimes be tricky to figure out which is the major premise and which is the sub-premise. To figure this out we can use the “Why should I believe that?” test again. Suppose I’m not sure which is the major premise: (b) The pianokey necktie, invented by Mugatu, became an important milestone in men’s fashion. OR (c) In the 80s, all the cool kids owned piano key neckties. Let’s apply the test.

A: Why should I believe that The pianokey necktie, invented by Mugatu, became an important milestone in men’s fashion?
BECAUSE in the 80s all the cool kids owned piano key neckties.

OR

B: Why should I believe that in the 80s all the cool kids owned piano key neckties?
BECAUSE The pianokey necktie, invented by Mugatu, became an important milestone in men’s fashion..

Clearly, A makes more sense. Whatever premise is the reason to believe the other is going to be the sub-premise.

Note about labeling premises: When arguments have more than two premises sometimes it won’t be obvious which to label P1, P2, P3, etc… In fact, it doesn’t matter which premise you label P1 and P2. so long as the bubbles in your diagram correspond to the way you labeled the premises when you put the argument into standard form the diagram accurately represents the structure of the argument and the relationship between premises. 

Let’s try one more example:

(a) Students seeking a rewarding career in any field should study philosophy because (b) philosophy will give you the tools to succeed. (c) Philosophy teaches you to write and think clearly at a high level. (d) For example, philosophy undergrads score the
highest of any other major on the LSAT and GRE tests.

The conclusion is (a). Now, to figure out the relationship of the other premises to each other and the conclusion we ask:

Why should I believe [(b) philosophy will give you the tools to succeed]?

The best answer is (c) philosophy teaches you to write and think clearly at a high level. That is support the claim that philosophy will give you the tools to succeed. We apply the test again to find out how the remaining premises are related:

Why should I believe [(c) philosophy teaches you to write and think clearly at a high level]?

The best answer is because (d), philosophy undergrads score the highest of any other major on the LSAT and GRE tests. This is evidence for the claim that philosophy teaches you to write and think clearly at a high level.

Now we can reconstruct the argument and show the logical relationship between the premises (and the conclusion).

P1. For example, philosophy undergrads score the highest of any other major on the LSAT and GRE tests.
P2. Philosophy teaches you to write and think clearly at a high level.
P3. Philosophy will give you the tools to succeed.
C. Students seeking a rewarding career in any field should study philosophy.

If you start at the conclusion and ask of it “Why should I believe that?” the next line up should give you the answer, and if you repeat the process it should work all the way up. Each line should be the answer to the line below it why you ask “why should I believe that?”

This is how serial premises work. They provide additional support for a more basic premise in the argument.

Here’s what the diagram should look like:

Screen Shot 2017-03-10 at 3.51.02 PM

Combining Convergent and Serial Premises

Extended arguments can use both convergent and serial premises. Let’s take a look at an example.

(a) Drinking tea is more communal than drinking coffee (b) since it’s more likely to be brewed in a pot. (c) Tea also has health benefits that coffee doesn’t. (d) For example it detoxifies the toxins and cures cancer. (e) Therefore, people should drink tea more often.

(e) is the conclusion. Now we ask, why should I believe that [(e) people should drink tea more often]? It looks like both (a) and (c) answer that question but they are unrelated to each other so they must be convergent premises.

So far my argument reconstruction looks like this:

P1. Drinking tea is more communal than drinking coffee.
P2. Tea has health benefits that coffee doesn’t.
C. Therefore, people should drink tea more often.

To show the structure of the argument I’ll start my diagram:

Screen Shot 2017-03-10 at 2.58.35 PM

Someone might challenge P1 or P2, or both. The arguer has anticipated this and provided additional support for those basic premises.

I ask:

Why should I believe that [P1 drinking tea is more communal than drinking coffee]?
BECAUSE (b) it’s more likely to be brewed in a pot.

Since (b) answers answers the question about P1, it’s a serial sub-premise.

My argument reconstruction now looks like this:

P1. Drinking tea is more communal than drinking coffee.
P2. Tea has health benefits that coffee doesn’t.

P3. Tea is more likely to be brewed in a pot.
C. Therefore, people should drink tea more often.

The way I’ve listed the premises we can’t see the relationship between P1 and P3. That’s what the diagram is for:

Screen Shot 2017-03-10 at 4.01.08 PM

One more step. I ask of P2:

Why should I believe that [P2 tea has more health benefits that coffee doesn’t have]?
BECAUSE (d) it detoxifies the toxins and cures cancer.

Since (d) answers the question, that is, give support to P2 we know it’s a serial sub-premise of P2.

My final argument reconstruction will look like this:

P1. Drinking tea is more communal than coffee.
P2. Tea has health benefits that coffee doesn’t.

P3. Tea is more likely to be brewed in a pot
P4. Tea detoxifies the toxins and cures cancer.
C. Therefore, people should drink tea more often.

Again, the way I’ve listed the premises doesn’t reveal the structure of the argument. I’m going to need a diagram for that:

Screen Shot 2017-03-10 at 4.06.15 PM

How I label the premises in the argument reconstruction doesn’t matter so long as my diagram shows the correct relations between them.

Looking Ahead

Recall that critical thinking is a systematic method of evaluating arguments, reasons, and evidence. Notice that now that we have systematically laid out the parts and structure of an argument it’s going to be much easier to evaluate it. We can look at each component individually and evaluate both whether it’s true and whether it genuinely supports the thing it’s supposed to support. Laying out the above argument should allow you to see that there are some weak premises as well as weak links between premises. This is the beginning of evaluating arguments. But notice that first you have to make the parts and structure explicit. Then and only then are you are much less likely to make errors in evaluating the argument. Critical thinking is the systematic evaluation of arguments, reasons, and evidence. Beat it into your head and you’ll be a smarty-pants in no time!

 

Homework

 

A. Indicator Words: Show the logical order of dependence indicated by the inference indicator word. Note: a single sentence can contain a premise and a conclusion.

Example 1: Since you’re not hungry I’m going to eat your dinner.

P1. Since you’re not hungry

C.  I’m going to eat your dinner.

Example 2: Usain Bolt is a wonderful example of a human being because he donated all the money he won to educate children in his community.

P1. Usain Bolt donated all the money he won to educate children in his community.

C. Usain Bold is a wonderful example of a human being.

Practice: 

 

1. He chose poorly therefore he melted, turned into a skeleton and died. 

2. As can be deduced from the pizza sauce all over his face, Otis Ponens ate the leftover pizza.

3. You’ll do fine in this course given that you will do all the homework and attend class.

4. BGSU is a great school. For example, they have a judo and grappling club.

5. Because he used his cellphone in class he is sadly no long with us. 

6. I increased my deadlift max by 10% thus I’m making gainz. 

7. Since the philosopher knows both the pleasure of the senses, of honor, and of the intellect, he is best suited to say which is more worthy of pursuit. (Paraphrasing Plato).

B. Each argument contains either serial premises or convergent premises or both. Reconstruct the argument into standard form and draw a corresponding argument diagram.

Example 1: Since France has banned the burkini for Muslim women, Muslim women from conservative families will have their freedom even more restricted than before. Therefore, if the French are truly concerned about the repression of Muslim women they ought to repeal the ban. 

Hint: Apply the “Why should I believe that” test to figure out which are the sub-premises and which are the main ones.

P1. France has banned the burkini for Muslim women.

P2. Muslim women from conservative families will have their freedom even more restricted than before.

C. If the French are truly concerned about the repression of Muslim women they ought to repeal the ban on burkinis.

Screen Shot 2017-03-10 at 3.35.36 PM

Example 2: Most voters aren’t rational or well-informed. For example, read the comments section of any online article. Do you really think democracy is a good idea? Besides, Plato argued that democracies always end up as populist tyrannies. 

P1. Plato argued that democracies always end up as populist tyrannies.

P2. For example, read the comments section of any online article.

P3. Most voters aren’t rational or well-informed.

C. Democracy isn’t a good idea.

Screen Shot 2017-03-10 at 4.15.18 PM

1. Golf isn’t a sport because it doesn’t require athleticism. For instance, you can drink and play at the same time. Also, just because an activity requires skill doesn’t make it a sport.

2. If you have the chance you should go to Japan. First of all, the food is amazing and so are the temples. The temple in Kyoto displays some of the most beautiful architecture anywhere in the world.

3. Crappy pizza just isn’t worth eating since I only allow myself to eat pizza as a reward. Besides, cheap pizza usually doesn’t even use real cheese.  

4. (a) We feel particular emotions only when we are in certain situations. (b) For example, I only feel sad when I’ve experience loss of something I care about. (c) Therefore, emotions aren’t merely feelings, they are judgments or appraisals about states of affairs that relate to our well-being. (d) Also, if emotions are just feelings you can’t explain why we only feel certain ones in similar situations. 

5. (a) You should buy the Ford Explorer instead of the Jeep Cherokee. (b) The Explorer gets better miles/gallon. (c) It has more cargo space. (d) And even though the Cherokee is better off road, you spend more time driving on paved roads.

6. People reward you for appearing moral rather than being moral. For example, one time I helped this old lady across the street to impress the girl I was with. The girl thought I was so nice she took me out to dinner. But another time, I told my friend not to invite a girl over because I knew her to be a thief. Instead of thanking me, he got mad at me. Therefore, it’s better to appear moral instead of be moral.

7. (a) Hillary Clinton is a law-breaker. (b) I heard that she removed the tag on her pillow that says “do not remove tag under penalty of law.” (c) And she breaks more than just criminal laws. (d) A staffer also recently reported seeing Hillary Clinton double-dipping a chip in the crab dip at a fundraiser. (e) Since she’s a law-breaker, people shouldn’t vote for her.

 

C. Construct or find TWO arguments that use either convergent or serial premises or both. Put the argument into standard form and make an argument diagram.

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