Argument Analysis: The Basic Method

Contact: Dr. Jan Garrett

Last revised date: February 16, 2004

Basic Terms

Let's get clear on some basic terms regarding reasoning.

Truth values: true, false.

Statement: a unambiguous declarative sentence (more technically: what is expressed by such a sentence); statements have truth-value (they are true or false), although, for a given statement, we may not know its truth-value.

Here are examples of relatively simple statements:

Socrates died from drinking hemlock.
My mind contains unclear ideas.
All humans are mortal animals.
No gods are mortals.
Here are examples of less simple statements (technically called compound statements):
If I pass this course, then I will be done with my Gen. Ed. requirements.
Justice is a type of action or [justice is] a quality of a person's soul.
All just persons are courageous and [all just persons are] wise.
It is not the case that Socrates is a fool.

Important Warning to Students Doing Argument Analysis

(Simple) Argument: a set of statements, one of which is the conclusion, the others of which are premises meant as support for the conclusion.


The gods have all the very best qualities. (Premise)
Intelligence is one of the very best qualities. (Premise)
Therefore the gods are intelligent. (Conclusion)
This argument might be informally expressed as: "We know that the gods are intelligent because the gods have all the very best qualities and intelligence is one of those qualities."

See Warning #3 Below.

(Complex) Argument: a set of statements, one of which is the final conclusion, the others of which are intermediate conclusions or ultimate premises meant as support of the final conclusion.

Informal Example:

Hear me now and believe me later. The stars are gods, for whatever is everlasting, intelligent and beneficial must be a god. And the stars have all three qualities. They don't seem to change, as anyone can observe. So they must be everlasting. They move in perfectly patterned ways, and whatever moves in perfectly patterned way displays intelligence. So they must be intelligent. What's more, the stars are beneficial because we are able to tell time accurately thanks to stellar movement.
Analyzed form:
In the formalized argument set out below,
     "P" designates a premise.
     "IC" designates an intermediate conclusion.
     "FC" designates the final conclusion.
     (See definitions below.)

(1, P) The stars don't seem to change.
(2, IC) They are everlasting beings. (1)

(3, P) They move in perfectly patterned ways.
(4, P) Whatever moves in a perfectly patterned way displays intelligence.
(5, IC) they are intelligent beings. (3, 4)

(6, P) The movements of the stars help us tell time accurately.
(7, IC) They are beneficial. (6)

(8, P) Whatever is everlasting, intelligent, and beneficial must be a god.
(9, FC) the stars are gods. (2, 5, 7, and 8)

This complex argument contains four interlinked simple arguments. The logic of the first three should be obvious. The fourth argument takes as premises the conclusions of the first three simple arguments (2, 5, 7), together with a new premise (8). The final conclusion (9) is the conclusion of the fourth simple argument.

Conclusion: the statement that is supposedly supported by the premises (reasons or grounds) in an argument.

Premise: a statement that is presented as support for a conclusion.

Intermediate conclusion: a conclusion that is meant to serve as a premise for a later conclusion (possibly the final conclusion of a complex argument). 2, 5, and 7 are intermediate conclusions in the complex argument given above.

Ultimate premise: within a complex argument, a premise that is not presented as supported by still other premises. (1, 3, 4, 6 and 8 are ultimate premises in the complex argument given above.)

Final conclusion: the conclusion of a complex argument, a conclusion that does not serve as a premise for any other conclusion in the same argument. 9 is the final conclusion of the complex argument example above.

Preliminary Argument Analysis

The first part of argument analysis is not concerned with whether the argument is a good one. It is not concerned with whether the premises are true or whether the argument is strong or valid, i.e., whether the premises actually support the conclusion as the author intends them to do. It is concerned only with understanding the reasoning process of the author. It aims to pick out the ultimate premises, the final conclusion, and any intermediate steps. Once we have taken apart such an argument and laid its structure out so that we can clearly see it, we can ask whether the premises are true and whether they really provide (probable or necessary) support for the intermediate or final conclusions.

A Suggested Procedure

1. Pick out the conclusion of the argument, the statement that is supposedly supported by other parts of the argument. (You may reword the text but make sure you don't alter the meaning.)

Sometimes you can tell a conclusion (intermediate or final) by the occurrence of key words. For instance, "so" and "therefore" frequently introduce a conclusion.
2. Then pick out the premises (or reasons) given in support of this conclusion. You may find that some statements supporting the final conclusion are meant to be supported by other statements. These are intermediate conclusions.
Sometimes you can tell a premise by the occurrence of key words: "For" (used as a conjunction, not as a preposition) introduces one or more premises (and typically follows a conclusion). "Because" and "since" often introduce one or more premises in an argument.
3. Note that because we are using "P" for premise in an argument reconstruction, there is no need to include "because," "for," or other premise indicators in the argument reconstruction itself, and that because we are using "IC" and "FC" to indicate intermediate and final conclusions, there is no need to use "therefore," or "so," or the like, in steps that are conclusions of either sort.

4. Sometimes there is a long chain of reasoning, with intermediate conclusions supporting other intermediate conclusions. If this is the case, try to show which intermediate conclusions are logically closer to the ultimate premises.

5. Be alert for implied (unstated) steps.

Sometimes the author assumes a premise without stating it, usually because he believes all his listeners or readers will automatically supply the premise. Sometimes there are implied intermediate conclusions or even implied final conclusions. If you detect an implied premise, intermediate conclusion, or conclusion, make it explicit. Sometimes doing so will reveal the weak point in an argument.

The argument from 6 to 7 above has an implied, i.e., unstated, premise:

"Whatever helps us tell time accurately is beneficial." (In this case the fact that the premise is unstated is relatively harmless.)
6. Sometimes, words or sentences within a passage of text that contains an argument will play no logical role at all. You can set those aside when you analyze an argument.
"Hear me now and believe me later" in the prose argument does no logical work at all. The phrase "What's more" is useful for indicating a new set of reasons in support of the ultimate conclusion, but it serves more as a grammatical divider than as a logical indicator. Both of these elements disappeared in going from the informal to the formal version of the argument.

Note to PHIL 120 students: Before you invest a lot of energy in your argument analysis, see how I think through an argument analysis of a passage from Plato's Republic (Thrasymachus on Justice). I don't expect students in PHIL 120 to write out all the steps of your thinking in such an explicit manner. But the more explicit you can be, the better your comprehension will be.

The skill of Argument Analysis is closely related to the important skill of Argument Construction. Read about Argument Construction.

Explanations, Predictions, and Causal Reasoning

Explanations pose special problems when they occur in the context of arguments: First, explanations can sometimes be partly restated (or disguised) as hypothetical arguments whose conclusion is a prediction. (By "hypothetical argument" I mean an argument one of whose premises is "supposed" or hypothesized so as to see what would have to be true, or would likely be true, if it were true.)

Second, some such arguments can be turned around and used to argue that the claim stated in the hypothesis, which is about an alleged cause, is supported by the occurrence of the event predicted. This is a form of reasoning from effect to cause. (It often occurs in the natural and social sciences but also in less scientific reasoning.)

Finally, once we have reached a conclusion regarding the cause of an event, that conclusion can be used to support further conclusions. For a relatively simple illustration and discussion of these patterns of reasoning, and how to do an argument analysis of them, see Explanations, Predictions, and Arguments.

Warnings about Mistakes to Avoid Regarding Statements

1. Questions do not clearly express statements, though some (such as rhetorical questions) can be reworded as declarative sentences in order to do so.

2. A set of two or more declarative sentences do not normally express a single statement. The exception occurs when they mean exactly the same thing, but nothing is gained by including two such statements in an argument analysis. Whenever you need to include more than one declarative sentence in your argument analysis, they should be included as separate statements with separate steps.

Of course, there are compound sentences, of the form "if p then q," "p and q," "p or q," etc., and they do express compound statements that do not have to be broken up and assigned to multiple steps when you are representing them in an argument analysis. However, if you have a compound statement as one of your steps, you might also have one of its components as an additional premise or a conclusion (since one can logically derive, for example, "p" from "p and q," and "q" from "p" together with "if p then q").

3. An argument (often indicated by the presence of words like "because," "since," "hence," "therefore") is not a statement, but two or more statements. It should be broken up into separate steps.

4. Sometimes the words "because" or "since" indicate not an argument but an explanation and the explanation is part of an argument from effect to cause. In some such contexts, a sentence containing "because" or "since" can be reworded as a statement that has the structure "The explanation for p's being true is that q is." (In a complete reconstruction of an effect-to-cause argument, there would be another premise that p and a conclusion that q.)

Note About Parenthesized Numerals After Statements

Numerals given in parentheses following a statement that is an intermediate or final conclusion refer to the steps that allegedly prove or support that conclusion. Providing such numerals will create a more complete and helpful argument reconstruction.