Every Quiz Has Been Easy Therefore the Test Will Be Easy Deductive or Inductive

Recognizing Inductive v Deductive Arguments

Patterns of Inductive Arguments

In recognizing inductive arguments look for these situations. All of the following would be inductive situations.

Premises that talk about:	Conclusion that talks about:
One, Some, Most Xs --->	Most, All Xs
Past events --->	Present events
Past and/or Present events --->	Future events
Time sequence of events ---> (A happened, then B happened)	Causal Connection between events (A caused B)

Any argument that fits one of these situations will be inductive, because the conclusion is a generalization in some way that goes beyond the type of evidence offered in the premises.

Examples for Inductive Argument Patterns

#1 One, Some, Most --> Most, All

Example #1

Some expensive cars are fast.
So, all expensive cars are fast.

#2 Past events --> Present event

Examples #2

Last semester, students who missed a lot of class meetings in this class did not pass the course.
So, this semester, students who miss a lot of class meetings in this class will probably not pass the course.

Last time there was a major international crisis, the stock market tanked for a few days. Smart people did not sell their stocks and when the crisis passed quickly they made lots of money by buying even more stocks when prices tanked during the crisis. So, I would not worry about Russia invading Ukraine and buy, buy, buy when the stocks tank for a few days.

#3 Past and Present events --> Future events

Example #3

For the past several decades the University has not been able to afford a competitive Division I football team.  This year again, we have a dismal record and the state funding for the University football team has been poor.  So, probably the University will not have a competitive Division I football team for the foreseeable future.

#4 Time sequence of evens --> Causal connection between events

Example #4

Before Clinton was president in the 1990s, the United States economy was pathetic and lots of people were losing their jobs.  After he became president, the economy boomed throughout the rest of the 90s and millions of new jobs were created.  So, it is likely that the Clinton presidency caused the economic boom throughout the 90s.

Patterns of Deductive Arguments

#1 General statement(s) in the premises --> Specific statements in the conclusion

Example #1

All the apples in the barrel are rotten.  So, one in the middle is rotten.

Example #2

Presidents of the United States are always wealthy.  So, Barack Obama must be wealthy.

Example #3

All the bananas at Time today are yellow.
Kanoe bought yellow bananas today.
So, Kanoe bought her bananas at Times.

#2 Hypothetical statements in the premises --> Linked statements in the conclusion

Example #1

If a person abuses drugs, legal or illegal, over time the person's immune system will be compromised.
If over time a person's immune system is compromised, then the person will be susceptible to more viral illnesses (cold and flu) and even cancer.
So, if person abuses drugs, legal or illegal, then the person will be susceptible to more viral illnesses (cold and flu) and even cancer.

Example #2

If we legalize gay marriage, it will become "normal" for our school textbooks to portray homosexual attraction as normal.  If it becomes normal for our school textbooks to portray homosexual attraction as normal, then at school dances boys and girls will be confused about who to invite and children will be confused on having to decide prematurely on their sexual identify.  If this happens, it will change our entire culture.  So, if we legalize gay marriage, it will change our entire culture.

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Source: http://www2.hawaii.edu/~pine/logicweb/tutorials/Recognizing-Induction-Deduction/Recognizing-Induction-Deduction.html

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