Finding Premises and Conclusions

How do we find the conclusion? The conclusion of an argumentative piece of writing (or speech) is the claim that the author intends for you to accept on the basis of the reasoning that has been given. It is the central point, or the proposition that all of the other claims support. It is the overall thesis that the author hopes to convince you to believe. There may be many claims that the author wants you to accept, but the conclusion, for our purposes, is the final, overall, most important claim that the other assertions ultimately support. If the piece is written and argued well, the central thesis will be immediately obvious from indicators that make it explicit, from the structure of the reasoning, or it will be implicit in the writing. There many be several points being made, or there may appear to be several arguments for different conclusions. If the piece is composed well, those subordinate arguments will lend support to the final, central thesis. It may help to ask, “which of the claims being argued for is the broadest in scope or the most general?” That will often reveal the central thesis.

Finding the conclusion in a piece of argumentative writing is where we start in our efforts to understand and then reconstruct the argument. How does one find the conclusion in a piece of argumentative writing? How do we determine what the conclusion is? Generally, there are three ways:

First, look for conclusion indicators in the writing. There are a number of explicit terms that authors will use to signify the thesis they are arguing for. Some of these terms can be obvious, such as: "therefore," "in conclusion," "it follows that," "we should draw the conclusion that," X "implies" Y, or X "because," Y, "so," or "clearly..." and so on.

Therefore, abortion in cases of rape or incest should be allowed by law.

We should draw the conclusion that the defendant is innocent.

The defendant is innocent because he was not present at the scene of the crime.

The absence of the compound in the chemical assay implies that Smith did not take steroids.

In some cases, the conclusion indicators can be less obvious with words such as, "because," "since," "hence," or "thus." With terms like "because," notice that the conclusion will come first and the reasons will come after: The defendant is innocent because he was not present at the scene of the crime. "The defendant is innocent," is the conclusion, and "He was not present at the scene of the crime." If attempt to put this argument into our standard form for reconstructed arguments, would look like this:

1. The defendant was not present at the scene of the crime.

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2. Therefore, the defendant is innocent.

Notice that this argument is not strictly valid yet. The conclusion is not guaranteed to follow from the truth of the premise. There is an implied premise that the author is relying on:

1. The defendant was not present at the scene of the crime. (EP)

2. If the defendant was not present at the scene of the crime, then the defendant is innocent. (IP)

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2. Therefore, the defendant is innocent. (1,2)

See the lectures on Reconstructing arguments for details about how to correctly reconstruct a full argument. (EP) and (IP) here indicate "explicit premise," and "implicit premise." (1,2) indicates that the conclusion follows logically/validly from premise 1 and premise 2. What's important here is that we correctly recognized the conclusion in the original piece of writing. Our first rule for finding conclusions should be: look for explicit conclusion indicators.

What are the other ways to find a conclusion? We can also look at the logical structure of the reasoning. We have been studying formalized arguments that have valid or cogent structures. If a passage contains claims that can be represented at “If P then Q,” and “Q,” and “P,” for instance, the obvious conclusion that could follow from what the author has said is “Q” from the premises “If P then Q,” and “P.” If we interpret the conclusion as “P,” in this case, we would be attributing an invalid, and poor argument to the author. If the author makes that sort of egregious logical mistake, and it is clear that she does in the passage, then that is her mistake and you must take her at her word. (Your first criticism of the reconstructed argument should be that it is invalid, so the conclusion does not follow from the premises even if they were true.) But if the author is being careful, and we are being charitable, attribute a valid argument to them if it is consistent with what is in the passage, all other things being equal. That is, get a sense of what the logical structure of the argument is, and that can help you identify the conclusion, if other methods fail.

Elaine isn't home. She went to class, and if she is in class, then she is not home.

The most natural way to reconstruct this argument that makes it valid is:

1. If Elaine is in class, then she is not home.

2. Elaine is in class. VALID

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3. Therefore, Elaine is not home.

No other arrangement of the sentences makes it valid or cogent:

1. Elaine is not home.

2. Elaine is in class. ILL-FORMED

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3. Therefore, if Elaine is in class, then she is not home.

1. If Elaine is in class, then she is not home.

2. Elaine is not home. ILL-FORMED

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3. Therefore, Elaine is in class.

In general, we want to reconstruct an author's reasoning as charitably and as strong as we can. So we should make it valid or cogent, if one of those argument patterns conforms with the author's writing. Sometimes an author makes an error in reasoning and employs ill-formed reasoning. In those cases, we can still determine what their conclusion is, but it may not be possible to charitably reconstruct their argument in a way that makes it valid or cogent without seriously changing their intent or reasoning. See the lectures on reconstructing arguments for more details.

So our second rule for finding the conclusion is, look at the logical structure of the reasoning to see what is logically implied by a valid or cogent reconstruction.

Our third rule for finding the conclusion is: Look for an implicit conclusion. In some cases, a premise or the conclusion are clearly implied by what the author says and by the logical structure of the passage. That is, a premise isn't stated explicitly, but it is clearly needed to make the argument valid or cogent, and the author has taken it for granted that the reader will see the implication. In these cases, take what has been explicitly written and try to put into either a valid or cogent argument form, and see if there is a missing premise that, if added, would make the argument valid of cogent, and the author appears to have assumed it. Implicit conclusions work the same way. See the lectures for Reconstructing Arguments for more details.

If you are in Calculus, then you must have passed Algebra 2. And Jacob didn't pass Algebra 2.

Here a conclusion is implied that isn't stated explicitly, but given the logical structure and what we know about Modus Tollens, we can infer:

1. If you are in Calculus, then you must have passed Algebra 2. (EP)

2. Jacob didn't pass Algebra 2. (EP) VALID

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3. Therefore, Jacob isn't in Calculus. (1, 2)

Attempting to reconstruct the argument in any other order, without the implied conclusion produces an ill-formed argument that misses the point:

1. If you are in Calculus, then you must have passed Algebra 2. (EP)

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2. Therefore, Jacob didn't pass Algebra 2. ILL-FORMED

Or,

1. Jacob didn't pass Algebra 2.

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2. Therefore, If you are in Calculus, then you must have passed Algebra 2. ILL-FORMED

So our three rules for finding conclusions:

1. Look for explicit conclusion indicators.

2. Look at the logical structure of the reasoning to see what is logically implied by a valid or cogent reconstruction.

3. Look for an implicit conclusion.

Finding Premises

When we reconstruct arguments, we start by figuring out what the conclusion is. What is the main point the author is trying to convince us of? Once we have determined what that target is, then we can work backwards to reconstruct the reasoning that the author intends for us to follow to get there. The goal with a strong argument for some conclusion that you don't already believe is to take grounds, or evidence, or premises that you do accept and then show how those claims logically imply the conclusion, so if you're reasonable, then you'll accept the conclusion. We've already seen that figuring out the conclusion requires us to decide what the premises are. When we search for the premises, we should ask ourselves this question: what are the reasons that the author is giving us that she thinks imply the conclusion? An important guide to finding those should be our knowledge of how deductively and inductively arguments structures work. With deductively valid or inductively cogent inferences in mind, we should ask, "What are the reasons here that fit into good logical inference structures that could imply the conclusion for the author? In many cases, particularly in the examples for this class, the reasoning will already employ some basic logical inferences and we can recognize premises and their role in that reasoning.

What is the first rule for finding premises in an argumentative passage: Find the conclusion, and the other claims needed to make a well-formed, charitable reconstruction will be premises.

Consider this example:

If we bring our troops out of Afghanistan too quickly, the government there will collapse. And the U.S. cannot suffer through the embarrassment of the foreign relations failure of a government collapse there. So we should not bring the troops out too quickly.

In this case, the last sentence is the conclusion indicated by "So," That means that the other sentences are either premises or they are extraneous. And we are familiar with "If P then Q" inferences. So the first sentence is clearly a premise: "If we bring our troops out of Afghanistan too quickly, the government there will collapse." The second sentence is a premise too, but we can eliminate the "And" as extraneous: "the U.S. cannot suffer through the embarrassment of the foreign relations failure of a government collapse there." Reconstructed, the argument looks like this:

1. If we bring our troops out of Afghanistan too quickly, the government there will collapse. (EP)

2. U.S. cannot suffer through the embarrassment of the foreign relations failure of a government collapse there. (EP)

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3. Therefore, we should not bring the troops out too quickly. (1,2)

Notice that the reconstructed argument with just the stated language is not yet valid. We need to make some revisions and add an implicit premise to make it valid:

1. If we bring our troops out of Afghanistan too quickly, the government there will collapse. (EP)

2. If the government there collapses, then the U.S. will suffer the embarrassment of a foreign relations failure. (IP)

3. The U.S. cannot suffer the embarrassment of a foreign relations failure. (IP)

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3. Therefore, we should not bring the troops out too quickly. (1,2, 3)

See the lectures on Reconstructing Arguments for more details. What's important here is that we correctly identified the premises and the conclusion in the first passage.

Consider this example:

If follows that all liberals are pro-choice since all liberals are progressives. And all progressives are Democrats. And all Democrats are pro-choice.

"All liberals are pro-choice." is the conclusion, but we leave off the "Since all liberals are progressives," because "since" separates the conclusion from a premise. Then if we list the premises in order with the conclusion in an attempt to reconstruct the argument, we must ask, is this argument valid?

1. All liberals are progressives. (EP)

2. All progressives are Democrats. (EP)

3. All Democrats are pro-choice. (EP)

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4. Therefore, all liberals are pro-choice. (1,2,3)

Yes, this argument is valid. We need all of the remaining sentences besides the conclusion to make a valid argument. So once we have found the conclusion, the rest of the claims in this case are premises.

Consider this argument:

Clearly, the governor is lying about how much he paid in state taxes last year. Most of the things that the governor says when he is speaking to the press are lies. The last time he spoke to the press about firefighter pensions, he misrepresented the amounts. And when he was speaking to the press, he told them he paid $17,040 in taxes last year.

In this case, "The governor is lying about how much he paid in state taxes last year." is the conclusion. So we might be tempted to list everything else as premises:

1. Most of the things that the governor says when he is speaking to the press are lies.

2. The last time he spoke to the press about firefighter pensions, he misrepresented the amounts.

3. When he was speaking to the press, he told them he paid $17,040 in taxes last year.

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4. Therefore, the governor is lying about how much he paid in state taxes last year.

This is a good start, but line 2 is extraneous. It's not needed to make the argument cogent, and it doesn't really add anything logically to the argument. The firefighter point isn't necessary as a premise to make the argument well-formed. This reconstruction and list of premises is better:

1. Most of the things that the governor says when he is speaking to the press are lies. (EP)

2. When he was speaking to the press, he told them he paid $17,040 in taxes last year. (EP)

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3. Therefore, the governor is lying about how much he paid in state taxes last year. (1,2)

So "The last time he spoke to the press about firefighter pensions, he misrepresented the amounts." is NOT a premise in this argument. It is unnecessary. The lesson here is that not everything that an author says is an essential logical part of the argument. And finding premises requires more thought than merely listing all of the other non-conclusion sentences verbatim. Trim and adjust the premises so that they conform to the logical structure that the author is employing.

So our rule for finding premises in an argumentative passage: Find the conclusion, and the other claims needed to make a well-formed, charitable reconstruction will be premises.

Examples: Here are some more examples of argumentative passages where we can find the conclusion and the premises. The answers are below:

A. I need to get a flu shot. If you want to decrease your chances of getting the flu, then you need to get the shot. I can’t afford to get sick this year.

B. If we bring our troops out of Afghanistan too quickly, the government there will collapse. And the U.S. cannot suffer through the embarrassment of the foreign relations failure of a government collapse there. So we should not bring the troops out too quickly.

C. No Republicans are suitable to be president because no Republicans are in support of gay marriage. And only candidates who are in support of gay marriage are suitable to be president.

D. The only abortions that should be legal are ones that are performed to protect the life of the mother. The value of one human being’s life is more important than any consideration except the life of another person. And a fetus is a human being.

E. If follows that all liberals are pro-choice since all liberals are progressives. And all progressives are Democrats. And all Democrats are pro-choice.

Answers:

A. Conclusion: I need to get a flu shot.

B. Conclusion: We should not bring the troops out of Afghanistan too quickly.

C. Conclusion: No Republicans are suitable to be president.

D. Conclusion: The only abortions that should be legal are ones that are performed to protect the life of the mother.

E. Conclusion: All liberals are pro-choice.