Inductive Reasoning

Inductive reasoning is never-ending!

One interesting thing that we have learned about inductive inference is that it is never final. New information can come along to further strengthen or weaken an inductive inference. This exercise gives you some practice in seeing how inductive reasoning can be strengthened and weakened with new information.

Prepare: To prepare for this prompt take a look at Chapters 5 and 6 in our book, paying special attention to the section titled “Inductive Strength” (including the section “A Closer Look: Using Premises to Affect Inductive Strength”).

Reflect: Fine an inductive argument that occurs in some online source (make sure to cite the source) or think of one that you have heard used in your life. Consider its strength and how it might be strengthened or weakened in light of further information.

Write: Present an example of inductive reasoning. Comment on the strength of the inference. State a premise that could be added that, if true, would strengthen the inference. Now list another premise that could be added that would weaken it again. Now add another premise that could be added to strengthen it yet again. Continue this process even more times if you are enjoying the process and find it interesting.

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Black swans and Hildegard "Whole Wheat," the notorious bread thief.

Inductive reasoning is never-ending because new information can challenge our heretofore strong conclusions. Consider: it used to be thought that all swans were white. "White" was part of the definition of swan. There was even a saying "very much like a black swan," which meant "something that can't exist." It's sort of like when we say "when pigs fly," or it's like a "square circle" --an impossibility. But then in the 16th century, Europe discovered the existence of Australia and with it, the existence of -- you guessed it! -- Black swans. Before Europeans knew black swans existed, their reasoning about the necessary whiteness of swans was strong. After the discovery of black swans, such reasoning became weak. 

This is the major difference between inductive and deductive reasoning. New evidence doesn't threaten deductive reasoning like it does inductive reasoning. (But new evidence won't improve deduction, either.) 

An example to help you with the prompt:

P1. I saw that lady take a loaf of bread without paying for it.

P2. Taking something without payment is stealing

P3. Stealing is a crime. 

P4. People who commit crimes are criminals

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C. That lady is a criminal

To strengthen the conclusion: The lady was purported to be the notorious bread thief, Hildegard "Whole Wheat" Smith. 

To weaken the conclusion: But! I heard from the baker that she prepaid for the loaf of bread yesterday, so she did not take it without payment, so she did not steal, so she is not a criminal. 

To strengthen the conclusion: But then! It turns out the money she gave was counterfeit money! So it wasn't true payment, so it was stealing!

To weaken the conclusion: However! It turns out Hildegard's bread thieving was part of a publicity stunt to raise money to fight poverty and hunger, and all bakers were truly compensated after the big reveal. 

To strengthen the conclusion: However! The lady I saw wasn't Hildegard Whole Wheat, but someone impersonating her! 

See how this could go on and on forever?