Critical Thinking Slide 8

CRITICAL THINKING & PRACTICAL REASONING

Session 8 – DEDUCTION VS. INDUCTION ( PART 1)

Session Overview
•Students will be thought how arguments are constructed in the forms of deduction and induction. This will be done in order to teach them the requirements of these arguments for intellectual acceptability.
•Goals and Objectives
At the end of the session, the student will
1. Be able to distinguish bad and good ways of distinguishing between deductive and inductive arguments.
2. understand the difference between particular and general statements.
3. Understand the difference between reference class and attribute class of a statement.

Session Outline
The key topics to be covered in the session are as follows:
•Topic One: ARGUMENT.
•Topic Two : THE TWO TYPES OF STATEMENT THAT APPEAR IN ALMOST EVERY ARGUMENT
(a) Particular Statement
(b) General Statement
•Topic Three: THE TWO TYPES OF ARGUMENT
(a) Deductive Argument
(b) Inductive Argument

Topic One
ARGUMENT

What is an ARGUMENT.
•In session 5, we were introduced to an argument as a passage that is made up statements with premises and one conclusion.
• The premises are the reasons or justifications that support the conclusion. And the conclusion is the claim or belief or opinion of the person making the argument.
•Examples:
1. All professional football players are rich. Essien is a professional football player.
Therefore Essien is rich.(conclusion)

2. Two independent witness claim they saw john commit the murder. John’s finger prints are all over the murder weapon and John himself confessed to the crime. So we can conclude that John committed the murder.(conclusion)
3. For all the number of times that teachers had gone on strike. It has been because the government has refused to pay their research and book allowances. This year, government mentioned that as part of the changes to be made in the educational sector, the book and research allowances will be “taken off” the educational budget. So I foresee a strike action taking place before the year ends.(conclusion)

Topic Two
THE TWO TYPES OF STATEMENT THAT APPEAR IN ALMOST EVERY ARGUMENT.

STATEMENT
•A statements can be defined as a sentence that can either be true or false.
• The premises and conclusion of an argument are all expressed in the form of statements. However the nature the statements are such that they come in two forms. The PARTICULAR STATEMENT and The GENERAL STATEMENT.
•But FOR statement to be particular or general its REFERENCE CLASS must first be determined.

What then is the REFERENCE CLASS of a statement.
•Every statement has two parts.
•The reference class:- this the grammatical subject of the statement.
E.g.1. Joshua and Kofi are reading in the library.
2. A small group of taxi drivers in Accra can speak Chinese.
•The attribute class:- this is the attribute or property or action that the statement tells us about the subject.( the predicate of the statement)
•E.g. 1. Joshua and Kofi are reading in the library.
2. A small group of taxi drivers in Accra can speak Chinese.

•However, it is the reference class part, of every statement that determines the type of statement.
•A PARTICULAR STATEMENT is a statement with a finite(countable) reference class(subject)
•Examples:
1. Joshua and Kofi are reading in the library ( two individuals)
2. The water in this person’s bucket is finish. ( one person’s bucket)
3. Accra is filthy. ( one city)
4. All the students in this class are Distance education students.

(we can get to know the total number of the students in the class). Thus they are all particular statement because their reference classes are countable(finite).
•A GENERAL STATEMENT on the other hand is a statement with an infinite(uncountable) reference class(subject).
•Examples:
1. A small group of taxi drivers in Accra can speak Chinese.
2. All students are distance education students
3. No human being can fly.
4. Some Ghanaians have not traveled before.
5. All students from University of Ghana read critical thinking.

We cannot count to know the total number of each reference class from the above examples. In e.g1 we cannot tell the exact number of small taxi drivers in Accra whether 20, 30, 60, 100, or 200. In e.g2 we cannot count the total number of students. It refers to students anywhere as well as those who are yet to become students. So it is infinite. The same can be said of e.g3. and e.g5. In e.g4 how many Ghanaians are “some”. The “some” can be half the population of Ghana or a quarter so it is also infinite.
• NB. Thus the two types of statement are particular and general statement. And very often the premises and the conclusion of any argument comprise these two types of statement. However note that they are not what makes a passage an argument but rather the presence of premises and conclusion.

Topic Three
THE TWO TYPES OF ARGUMENT

DEDUCTIVE AND INDUCTIVE
•The two types of argument are deductive argument and inductive argument. But before we look at what they essentially are, let’s consider the inappropriate or wrong way to define an inductive argument and deductive argument.
•The mistaken way of distinguishing an inductive argument from deductive argument is to define inductive argument as:
•the type of argument that moves from particular statements as premises to a general statement as conclusion E.g.
1. I saw ten vandals and they were all wearing red.(particular statement)premises. So I can conclude that all vandals wear red. (general statement) conclusion.

•And define Deductive argument as the type of argument that moves from general statement as premises to particular statement as conclusion.
• E.g.
1. All vandals wear red.(general statement)premise
Ten vandals are visiting me today.(particular statement)premise
So they must wear red.(particular statement)conclusion
•NB. To define inductive and deductive this way is to claim that all inductive and deductive arguments look like this always. But this is false because not all inductive and deductive arguments look like this. The above definitions are too narrow.

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