Diagramming Arguments - Notes PDF

Preview

Summary

notes...

Description

Diagramming Arguments In order to analyze simple and complex arguments, we will find it useful to construct a diagram of the structure of the argument that details the relations among the various premises and conclusions.

1.

A.

A conclusion of one argument can become a premise for another argument. Thus, a statement can be the conclusion of one argument and a premise for another argument just as a daughter in one family can become a mother in another family.

B.

The number of arguments in a passage is conventionally established by the number of conclusions in that passage.

C.

In analyzing the structure of an argument, whether simple or complex, the allimportant first step is to find the conclusion. Here are some specific suggestions as to how to find the conclusion.

The conclusion might be evident from the content and context of the paragraph structure. The sequence of sentences is often an indication of the conclusion. Arrangement of sentences from most general to specific is a common form of paragraph or passage; the arrangement of sentences from specific to general is a bit less common. Considering both cases, the conclusion is often the first and sometimes the last sentence in a passage. Example: (1) John didn't get much sleep last night. (2) He has dark circles under his eyes. (3) He looks tired

The conclusion is the first sentence in the passage. 2.

Nevertheless, the conclusion can occur anywhere in the paragraph, especially if the passage has not been revised for clarity. Usually, if a conclusion is not the first or last sentence, a conclusion indicator is present, or the last sentence is presented as an afterthought with a premise indicator. See below for lists of premise and conclusion indicators.

Example: (1) Studies from rats indicate that neuropeptide Y in the brain causes carbohydrate craving, and (2) galanin causes fat craving. (3) Hence, I conclude that food cravings are tied to brain chemicals (4) because neuropeptide Y and galanin are brain chemicals.

The structure of the argument (and, of course, the conclusion, as well) might be inferred by the following kinds of indicators a.

Premise indicators are words which often indicate the presence of reasons. Common premise indicators include the following: for since as because for the reason follows from after all in light of the fact *for the reason Example Argument: (1)The graphical method for solving a system of equations is an approximation, (2) since reading the point of intersection depends on the accuracy with which the lines are drawn and on the ability to interpret the coordinates of the point.

Another example argument: (1) Questionable research practices are far more common than previously believed, (2) after all, the Acadia Institute found that 44 percent of students and 50 percent of faculty from universities were aware of cases of plagiarism, falsifying data, or racial discrimination.

b.

Conclusion indicators are words which often indicate the statement which logically follows from the reasons given. Common conclusion indicators include the following: thus therefore consequently hence so it follows that proves that indicates that *accordingly implies that *for this reason Examples of their use in arguments: (1) No one has directly observed a chemical bond, (2) so scientists who try to envision such bonds must rely on experimental clues and their own imaginations.

(1) Math grades for teens with bipolar disorder usually drop noticeably about one year before their condition is diagnosed, thus (2) probably bipolar disorder involves a deterioration of mathematical reasoning.

(1) Coal seams have been discovered in Antarctica. (2) This means that the climate there was once warmer than it is now. (3) Thus, either the geographical location of the continent has shifted or the whole Earth was once warmer than it is now.

c.

Conjunctives (including conjunctive adverbs) often indicate equal status for clauses or sentences. Noticing these conjuncts is especially helpful for argument analysis if one of the elements has already been identified. Indicators of clauses of equal status include: and but yet however moreover in addition nevertheless (and also the semicolon ";") Examples: (1) Some students absent today are unprepared for this test, since (2) the law of averages dictates that only 10% of students are absent due to illness, and (3) more than 10% are absent.

(1) Lenses function by refracting light at their surfaces. (2) Consequently, not only does their action depends on the shape of the lens surfaces but also (3) it depends on the indices of

refraction of the lens material and the surrounding medium.

When working with complex arguments, it is often helpful to reconstruct the argument backwards from the conclusion. Consider the following argument.

(1) If students were environmentally aware, they would object to the endangering of any species of animal. (2) The well-known Greenwood white squirrel has become endangered (3)as it has disappeared from the Lander Campus (4) because the building of the library destroyed its native habitat. (5) No Lander students objected. (6) Thus, Lander students are not environmentally aware. 

The premise indicators suggest that (2) is a sub-conclusion of (3) since the indicator "as" connects them, and (3), in turn, is a sub-conclusion of (4) since the indicator "because" connects those two statements.



Statement (6) is the final conclusion since it has the conclusion indicator "thus" and the import of the paragraph indicates that this statement is the main point of the argument.



Intuitively, the structure of the first statement (1) together with statement (5) is a common argument form: If students were environmentally Aware, they would Object to the endangering of any species of animal. No student Objected (to the endangering of the Greenwood white squirrel). Which can be abbreviated as follows: If A then O Not O and the negation of clause O is logically equivalent to conclusion (6). If A then O Not O

Not A which is the same statement as (6).

Hence the whole argument can now be pieced together as:

Types of arguments (1) Paris is in France, and (2) France is in Europe. So obviously (3) Paris is in Europe. Here is the corresponding argument map: Note that the two premises are connected together before linking to the conclusion. This merging of the links indicate that the two premises are co-premises which work together in a single argument to support the conclusion. In other words, they do not provide independent reasons for accepting the conclusion. Without one of the premises, the other premise would fail to support the conclusion. This should be contrasted with the following example where the premises are not co-premises. They provide independent reasons for supporting the conclusion: [1] Smoking is unhealthy, since [2] it can cause cancer. Furthermore, [3] it also increases the chance of heart attacks and strokes. This diagram tells us that [2] and [3] are independent reasons supporting [1]. In other words, without [2], [3] would still support [1], and without [3], [2] would still support [1]. (Although the argument is stronger with both premises.)

Finally, it is also possible to have a single reason giving rise to multiple conclusions: [1] Gold is a metal. [2] So it conducts electricity. [3] It also conducts heat.

More Complex Examples Now that we know the basics of argument maps, we can combine the templates we learn above to represent more complicated arguments, by following this procedure: 1. Identify the most important or main conclusion(s) of the argument. 2. Identify the premises used to support the conclusion(s). These are the premises of the main argument. 3. If additional arguments have been given to support any of these premises, identify the premises of these additional arguments as well, and repeat this procedure. 4. Label the premises and conclusions using numerals or letters. 5. Write down the labels in a tree structure and draw arrows leading from sets of premises to the conclusions they support. Let us try this out on this argument: Po cannot come to the party because her scooter is broken. Dipsy also cannot come because he has to pick up his new hat. I did not invite the other teletubbies, so no teletubby will come up to the party. We now label and reformulate the premises and the conclusions: (1) Po cannot come to the party. (2) Po's scooter is broken. (3)Dipsy cannot come to the party. (4) Dipsy has to pick up his new hat. (5) I did not invite the other teletubbies. (6) [Conclusion] No teletubby will come up to the party.

This is an example of what we might call a multi-layered complex argument, where an intermediate conclusion is used as a premise in another argument. So [1] and [3] are the intermediate conclusions, which together with [5] lead to the main conclusion [6]. This complex argument is therefore made up of three overlapping simple arguments in total. Of course, in this particular

case you can understand the argument perfectly well without using this diagram. But with more complicated arguments, a picture can be an indispensable aid.

Exercise: Draw argument maps for the following arguments: 1. 1This computer can think. So2 it is conscious. Since 3we should not kill any conscious beings, [4] we should not switch it off. 2. 1Many people think that having a dark tan is attractive. 2But the fact is that too much exposure to the sun is very unhealthy. 3It has been shown that sunlight can cause premature aging of the skin. 4Ultraviolent rays in the sun might also trigger off skin cancer. 3. 1If Lala is here, then 2Po should be here as well. It follows that if3 Po is not here, 4Lala is also absent and 5indeed Po is not here. 6So most likely Lala is not around. 4. Marriage is becoming unfashionable. Divorce rate is at an all-time high, and cohabitation is increasingly presented in a positive manner in the media]. Movies are full of characters who live together and unwilling to commit to a lifelong partnership]. Even newspaper columnists recommend people to live together for an extended period before marriage in order to test their compatibility. 5. All university students should study critical thinking. After all, critical thinking is necessary for surviving in the new economy] as we need to adapt to rapid changes, and make critical use of information in making decisions. Also, critical thinking can help us reflect on our values and purposes in life. Finally, critical thinking helps us improve our study skills. 6. 1 I don’t hate cheerleading just because 2it’s about as safe as porcupine-juggling. I also hate it because 3 it’s dumb. 4 The Velcroed-on smiles. 5 The bizarre arm movements stolen from the Navy signalmen’s handbook. 6 The same cheers done by every troupe in every state....