Formal Logic
Argument Tests
Fallacies
Conducting a Survey

Argument Structures Review

Formal Logic

• Definition: Formal Logic • Structure: Cause - Effect •
• Structures: Inductive Argument •

A difficulty that students encounter when participating in Lincoln-Douglas debate is the ability to communicate their ideas to the judge. The debater understands what he is trying to say, the debater knows that his position is the correct position, and the debater believes he should win the round. However, what the debater thought he said and what the judge heard may be two totally different things. To help alleviate this problem, a debater should understand the basic structure of an argument, identify those arguments that are flawed, and be able to compose a sound argument.

Definition: Formal Logic

• ArgumentationArgumentation is the art of justifying claims by offering reasons and evidence.
• Reasoning is the art drawing conclusions based on specific examples, instances, facts, or sound opinions.
• Induction is the art of drawing general conclusions based on specific bits of information.

Structures: Inductive Argument

• Example: In a recent poll seeking opinions about the practicality of a 3 year high school diploma:

• 19 out of 23 teachers voiced reservations.
• 2 out of 3 school administrators voiced reservations.
• 12 out of 22 students voiced reservations.
• Most people think a 3 year high school diploma is a bad idea, and the plan should not be implemented.

• Components: The parts of a formal argument include:

1. Premise: Evidence - the specific fact, detail, example, opinion, or statistic.
2. Conclusion: The summary derived or induced from the premises.

• Explanation: Inductive arguments take specific incidents and apply them to generalized conclusions. In-other-words, inductive reasoning proceeds from a few to the whole. The foundation for using inductive arguments lies in our inability to test or prove what will happen in the future and our inability to ask everyone for their opinion. Therefore, we must resort to looking at a few test cases and from those cases imply that what is true for those specific cases will be true for every case, or nearly every case. A survey is the perfect example of an attempt to develop an inductive argument. Inexact, but the best we have.

Structure: Cause - Effect

• Example: Consuming alcoholic beverages impairs the senses.

1. Impairment of the senses causes the body to react slowly.
2. Slow reaction causes traffic accidents.
3. Traffic accidents cause the loss of life.
4. Consuming alcoholic beverages causes the loss of life.

• Components:

1. Cause - consuming alcoholic beverages
2. Links - impaired senses, slow body reactions, traffic accidents
3. Effect - loss of life

• Explanation: Cause/effect arguments are a specific type of inductive reasoning. Along with looking at a number of specific test cases, the cause/effect argument concentrates on the relationship or links between an event and the outcome. It is absolutely necessary to include the links when presenting an argument otherwise the relationship is broken and the argument sacrifices credibility.

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Argument Tests

In order to determine whether a debater's arguments are sound and in order to exploit the flaws in his opponent's arguments, a debater should use four tests to examine each argument. Debaters frequently work with the first test but rarely employ the other three tests. This is a serious error, because debaters are only running ¼ of the full range of possibilities.

• Validity: having legal strength or force; well grounded or justified
  • Premises must be True.
  • Premises must be Representative of the population.
  • Premises must be a sufficient Sampling.
  • Conclusion must be Drawn from the premises.
• Invalid Arguments: The argument presented is poorly grounded.
  • Premise is not true. One or more portions of evidence are false, e.g. in the argument above; in actuality, only 4 teachers opposed a 3 year diploma; 4 fully supported it; and 16 requested more information, were undecided, or had only minor reservations.
  • Premise is not representative. One or more pieces of evidence do not represent the true population concerned with the issue, e.g. in the argument above, parents were not surveyed and their opinions should be represented.
  • Premise is not of sufficient sampling. One or more pieces of evidence do not cover sufficient territory to be considered accurate, e.g. in the argument above, only 22 of over 200 students were surveyed and no indications were given of how students were selected for the survey. Were they Honor students, Special education, Gifted/Talented, athletes?
  • Conclusion cannot be drawn from the premises. The premises do not point to the conclusion drawn, e.g. in the argument above, "reservations" does not necessarily mean "bad idea."
• Valid Arguments: The argument is well grounded and justified.

In a recent poll eliciting opinions about a 3 year high school diploma: 19 out of 23 teachers voiced some reservations on the issue. 2 out of 3 school administrators voiced reservations. 32 out of 40 parents of incoming freshman voiced concerns. 168 out of 206 students voiced reservation. Of those surveyed, most people voiced concern over a 3 year high school diploma, and further study should be conducted before implementing or eliminating such a program.

• It is impossible to prove anything using inductive reasoning so do not try to argue that your opponent did not prove something and do not waste your time searching for the "perfect" argument. Your goal is to use credible arguments that will persuade and to identify weaknesses in opponent's arguments.
• Evidence Test Exercise: Test the validity of each of the following arguments. If an argument is invalid, state the reason - unrepresentative, insufficient sampling, or conclusion cannot be drawn from the premises. One argument is valid; the other two are invalid.

1. 10 high school students were surveyed. 6 of the 10 preferred block scheduling to 7 period days. 3 high school teachers were surveyed. 2 of the 3 preferred block scheduling over 7 period days. The school should switch to block scheduling.
2. 8 of the 9 preferred block scheduling to 7 period days. 11 of the 12 bus drivers were surveyed. 9 of the 11 preferred block scheduling over 7 period days. The school should switch to block scheduling.
3. 100 high school students were surveyed. 87 % stated that they would prefer a block schedule over a 7 period day. 20 high school teachers were surveyed. 17 stated they would be willing to give block scheduling a chance. The school administration was surveyed. Both administrators said it was worth looking into. The school should investigate block scheduling.

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